2023 年度
SSH 生徒課題研究集録（抜粋）

2024 年 3 月
立命館高等学校
スーパーサイエンスコース
SSG クラス

研究成果一覧
分野

テーマ名

ページ

ショウジョウバエの行動に対する嗅覚の影響
Olfactory Influences on Behavior in Drosophila★第 13 回バイオサミット in 鶴岡 決勝出場 口頭発表 優秀賞

3-17★令和 5 年度 SSH 生徒研究発表会 ポスター発表賞★奈良県立青翔高等学校第 8 回サイエンスギャラリー ポスター発表
生物 カビの抑制に影響を及ぼす物質について
Substances Affecting Mold Suppression★奈良県立青翔高等学校第 8 回サイエンスギャラリー ポスター発表

18-30★奈良県立奈良高等学校けいはんなサイエンスフェスティバル

ポスター発表★ISSF（オーストラリアでのサイエンスフェア） ポスター発表
アントシアニンを用いた日焼け止めクリームの開発
Exploring the Photoprotective Capabilities of Anthocyanin★ICRF（国際共同研究合同発表会） 口頭発表（オンライン）

31-47

化学 ★National Junior College（シンガポール）校内発表会 オンライン発表
抹茶を用いた水溶液中の銅(Ⅱ)イオンの捕集除去実験
Collecting and Removing Heavy Metal Ions in Water Using Matcha

48-60★日本化学会近畿支部高等学校中学校化学研究発表会「奨励賞」
傘の形状の違いと表面に残る雨水の関係について
The Relationship between different Shapes of umbrellas
工学and Raindrops that Remains on the Surface★奈良県立青翔高等学校第 8 回サイエンスギャラリー ポスター発表

61-73

和音に最適な周波数の比
Optimal Frequency Ratio for Chords
数学 ★奈良県立奈良高等学校けいはんなサイエンスフェスティバル ポスター発表

74-87★ISSF（オーストラリアでのサイエンスフェア） 口頭発表
★Japan Super Science Fair 2023 口頭発表
動画解析による生徒の授業参加状態数値化システムの開発
Development of a Student Status Estimation System
情報for High School Classrooms★ASMS ISF 2023（オーストラリアのサイエンスフェア） 本校代表発表

88-101

フルートの音色の物理的解析方法
Method to Analyze Main Techniques of Flute Playing★Japan Super Science Fair 2023 口頭発表

102-116

物理 太陽放射と近くの天体の反射スペクトルの比較
Comparison between Solar Radiation
and Reflectance Spectrum of Nearby Astronomical Objects★Japan Super Science Fair 2023 口頭発表（韓国 KSA of KAIST と共同）

117-128

環境

効果的かつ海の生態系を守る人工リーフの実用化について
Artificial reef with effective shape and protection of marine ecosystems★サイエンスキャッスル関西大会★マリンチャレンジ関西大会★ASMS ISF 2023（オーストラリアのサイエンスフェア） 本校代表発表★Japan Super Science Fair 2023 口頭発表

129-143

ショウジョウバエの⾏動に対する嗅覚の影響

要旨

この研究の⽬的は、匂いなどの環境の変化がショウジョウバエの⾏動にどのような影響を与える
かをよりよく理解し、親の学習能⼒が次世代にどのような影響を与えるかを明らかにすることである。この実験では、2 つの物質の匂いの違いによってハエの⾏動がどのように変化するかを知るために、3D プリンターを⽤いて V 字型の装置を作った。実験では絶⾷状態に置かれたショウジョウバ
エが使われた。その結果、トラック内でショウジョウバエが最も活発に活動する絶⾷時間は約 24 時
間であることが判明した。次に、ショウジョウバエが匂いによってどの物質を餌として認識するかを調べる実験を⾏った。この実験では、通常の培地から酵⺟、プロピオン酸、およびその両⽅を組み合わせたものを除いた培地を作った。V 字型トラックの両端に通常培地と改良した培地をそれぞれ置き、5 匹のショウジョウバエをスタート地点に置き、約 10 分間観察した。この実験での観察か
ら、ショウジョウバエは酵⺟とプロピオン酸の匂いを頼りに培地にたどり着くことが⽰唆された。
この結果は、⽔で湿らせたコットンと酵⺟とプロピオン酸を使って実験を繰り返すことで確認された。装置内での⾏動に及ぼす雌雄の影響を調べたところ、ほとんど影響はなかった。そのため、個体群密度の違いを調べると、装置内での動きに違いがあることがわかった。

ハエの⾏動に与える影響についても検討するこ

1.背景

私は幼い頃から⽣き物に興味があり、⽣態や⾏とにした。特にハエを育てた培地の匂いをハエが動に特に関⼼があったので、⾏動学について研究

どのように認識しているかについて考察した。

しようと思った。⾼校⽣活という限られた時間の中で効率よくサンプル数を揃えるため、世代時間

2.方法が短いショウジョウバエを⽤いることにした。
William G. Quinn らによるショウジョウバエの条2－0. 培地の作り方

件⾏動に関する論⽂を読んだところ、それらの研材料（表１）を混合した。その後、それらを沸究では⼀度に 30 匹以上のハエを⽤いて実験を⾏騰させ、弱⽕で 15 分間加熱した。⽕を⽌めた後、っていた。ヒトの場合匂いは例えば、個⼈で⾷事

プロピオン酸とエタノール 6.5ml に p-ヒドロキシをするときと集団で⾷事をする場合などでは差

安息⾹酸ブチルを 6.5g 混合した溶液を加えて混が⽣じることが多いと感じ、多数のハエを⼀度の合した。混合物を試験管に⼊れ、⼀晩室温で静置実験に使⽤することは本来の⾏動とみて良いのして試験管内の湿度を下げた。

か疑問に感じた。また、ショウジョウバエにおい

表1 標準培地の成分表 1. 標準培地の成分ては個体群密度によって⽣殖⾏動や機能が影響

水(mL)
乾燥酵母(g)
コーンフラワー(g)
米ぬか(g)
グルコース(g)
粉末寒天(g)プロピオン酸(mL)
ヒドロキシ安息香酸/エタノール(mL)を受けること、トノサマバッタにおいては個体群密度によって相変異することが知られている。そこで、私は装置内での個体密度がショウジョウバ
エの⾏動にどう影響するのかの解明に取り組むことにした。同時に、その他の要因が装置内での

-3-

270
10
10
4
20
1.3
1.3
1.3

表 2. 絶⾷時間の実験
2－1. 飼育方法①
fasting duration

約 20 匹のハエを標準培地の⼊った試験管で飼育した。飼育環境の条件は、温度 23℃、明期 12時間、暗期 12 時間である。ハエの⽣活環は約 2 週

②

③

24h

④

⑤

⑥

9 h 6 h 40 min 5 h 15 min 4 h 10 min 1h 35 min

stay

0

7

7

10

11

moving

15

6

4

3

2

14
2

parameter

15

13

11

13

13

16

間のため、約 2 週間後、新しい培地にハエを移し

表 3. 実験結果(コントロール 1)

た。また、実験装置にハエを移したり、培地にハ

2023.04.13.16:00

エを戻したりする際に⼆酸化炭素を使⽤した。
2－2. コンディションの確認

キ イ ロ シ ョ ウ ジ ョ ウ バ エ （ Drosophila

①

②

③

④

total

stay

0

4

3

1

8

nomal

2

1

1

1

5

no food

3

0

1

3

7

melanogaster）の野⽣型（Oregon-R)は京都⼯芸繊

表 4.実験結果(コントロール 2)

維⼤学のショウジョウバエ遺伝資源センターよ2023.05.03.14:00

り⼊⼿した。予備実験において、培養したハエを

stay

1

1

0

0

2

図１のような V 字型装置におき、⽚側に餌を置いnormal

4

4

5

5

18

てハエの動きを⾒たところ、全然動かなない、まno food

0

0

0

0

0

①

②

③

total

④

たはエサの⽅に⾏かない個体が多く⾒られ、ハエが餌の匂いによって⾏動するかどうかの実験が2－3. 匂いできなかった（表 2）。実験を⾏う前、ハエを寒天

V 字型の装置の⽚⽅に改造した餌（標準の餌培地に移すことで絶⾷状態にしているのだが、今から酵⺟を抜いたもの、プロピオン酸を抜いた

回の結果から絶⾷時間を 1 時間半、4 時間、5 時

もの、酵⺟とプロピオン酸の両⽅を抜いたもの）

間、6 時間半、9 時間、24 時間と設定し、同様のを、もう⽚⽅には標準の餌を置き、スタート位

実験を⾏った。その結果、24 時間の絶⾷時間が最置に 5 匹のハエを置いて装置内での⾏動を観察も多く餌の⽅へと移動した（表 3）。したがって、した（図２）。また、餌からプロピオン酸と酵⺟

以降の実験では 24 時間絶⾷させた個体を⽤いた。

を加えた溶液をコットンにしみこませ、装置のまた、各実験においてハエの⽣育段階を揃えるた⽚⽅に置いた。もう⼀⽅は⽔を含ませたコット

めに実験を⾏う⽇の 3~1 ⽇前に試験管にいるハンを置いた（図３,４）。本当にハエがそれらのエを全て移し替え、変態後１〜４⽇間の個体のみ匂いがある⽅に向かうのかを約 10 分間ビデオ

で実験を⾏った。さらに各実験においてハエのコを撮って観察した。

ンディションを確認するため、毎回、24 時間絶⾷させた 10 匹以上のハエを V 字型装置（⽚側にのModifiedfood

みエサをおいた状態）のスタート地点におき、７割以上のハエがエサの⽅に移動することを確認した。
normalNofoodnormal

図2.2.V字型装置
図V 字型装置start

図1. V字型装置

-4-

start

2－4. 装置の形

3. 結果と考察

3D プリンターで作製した V 字型またはＩ字型

3－1. 匂いの装置の⽚⽅にプロピオン酸と酵⺟を加えた

V 字型の装置の⽚⽅に標準の餌、もう⽚⽅に溶液を染み込ませたコットンを置き、もう⼀⽅酵⺟を抜いた餌、またはプロピオン酸を抜いたには⽔を含ませたコットンを置き、スタート位

餌を置いて実験したところ、結果にあまり差は置に 5 匹のハエを置いて装置内での⾏動を観察なかった。しかし、プロピオン酸と酵⺟を抜いした。

た餌を置いて実験したところ、25 匹中 22 匹が改造前の餌の⽅へ向かっていった。コットンを

water

⽤いた実験でも同様に、40 匹中 30 匹が酵⺟とプロピオン酸の匂いを染込ませたコットンの⽅へ向かった。この結果から、ハエが匂いによodorって餌として認識する物質は、酵⺟とプロピオ

start

ン酸であることが⽰唆された。

図3. V字型装置

表 5. 実験結果(プロピオン酸なし)
water

start

odor

2023.04.05.10:00

図4. I字型装置

①

②

③

④

⑤

total

stay

0

3

1

1

2

7

nomal

4

1

2

3

1

11

without propionic acid

1

1

2

1

2

7

2－5. 雌雄V 字型の装置の⽚⽅に標準の餌を置き、もう表 6. 実験結果(酵⺟なし)
①

②

③

④

⑤

⽚⽅には何も置かず、スタート位置に 5 匹のハ

2023.04.20 14:00

エを置いて装置内での⾏動を観察した。その後、

stay

1

2

1

1

0

5

nomal

2

2

2

3

5

14

without yeast

2

1

2

1

0

6

実体顕微鏡下で尾部の⾊の違いによって雌雄を確認した。

total

表 7. 実験結果(プロピオン酸と酵⺟なし)
2－6. 個体群密度①

2023.04.21. 16:00

②

③

④

⑤

total

V 字型の装置にコットンを使った匂いの実験

stay

0

0

0

0

0

0

と同様に、⽚⽅にプロピオン酸と酵⺟を加えた

nomal

5

4

5

5

3

22

溶液を染み込ませたコットン、もう⼀⽅に⽔をwithout yeast & propionic acid

0

1

0

0

2

3

含ませたコットンを置き、スタート位置におく

表 8. コットンを⽤いた実験の結果
2023.04.27.16:00 / 2023.04.28.16:00

ハエの数が 5 匹の場合（同じ試験管で育ったハエ）と、1 匹の場合での実験を⾏い、⾏動を観察した。また、異なる試験管で育った 5 匹のハエをスタート位置に置き、同じ実験を⾏った。
実験後、装置内でのハエの軌跡を動画の上から

①

②

③

④

⑤

⑥

⑦

total

⑧

stay

2

1

0

2

1

1

2

0

water

0

1

0

0

0

0

0

0

1

yeast & propionic acid

3

3

5

3

4

4

3

5

30

3－2. 装置の形

I 字型の装置を⽤いて⾏った実験と V 字型のなぞって書き出した。それらを匂いの部分と⽔装置を⽤いて⾏った実験では同様の結果が得の部分に分け、それぞれのハエの軌跡を ImageJられた。よって、⼆つの形の違いは装置内でので測定した。

ハエの⾏動に影響を及ぼさないことがわかった。Timothy D. Wiggin らの研究では V 字型の装置を⽤いて実験が⾏われていたので私も V 字型

-5-9の装置を使って実験を⾏うことにした。

った。これらから装置内でのハエの動きに密度が関係しているかもしれない。

表 9. 実験結果(I 字型)①

2023.05.04.14:00 (I)

②

③

④

total

stay

1

2

0

2

5

water

0

0

0

1

1

yeast & propionic acid

4

3

5

2

14

④

total

odor

start

water

表 10. 実験結果(V 字型)
2023.05.04.14:00 (V)

①

②

③

stay

2

3

0

0

5

water

0

1

0

2

3

yeast & propionic acid

3

1

5

3

12

3－3. 雌雄それぞれの⽅向へ向かったハエの数が同じだった実験に⽤いた個体の雌雄を調べたとこ
ろ、テスト 1 回⽬では、雌 4 匹、雄 1 匹、2 回⽬では雌 1 匹、雄 4 匹だった。これらの結果か
ら雌雄の差が装置内のハエの⾏動に影響を及
ぼさないことがわかった。Tim Tully らによれば、雌雄は影響しないと報告されている。⼀⽅、Damien Mercier らの論⽂では、雄のハエから分図 5. 軌道図(5 匹) N=10
図5.
軌道図 (5匹) N=10

泌されるホルモンによってメスやオスが寄ってくることが報告されており、⼀概に雌雄の影響がないとは⾔い切れない。しかし、本実験においては、雌雄の差が⾒られないことから、短時間であれば影響しないと考え、他の実験では雌雄の差を考慮せずに実施した。
表 10. 軌道図(5 匹) N=102023.04.20.14:00

①

②

③

④

⑤

total

stay

0

2

1

1

1

5

nomal

5

3

4

4

4

14

no food

0

0

0

0

0

6

M:1

M:2

M:4

M:1

M:2 M:10

F:4

F:3

F:1

F:4

F:3 F:15

sex

M; maleF; female

3－4. 個体群密度

匂いの部分と⽔の部分を⽐較すると、ハエは匂いの部分に向かう傾向があることがわかった。また、1 個体だけの実験よりも 5 個体での実験の⽅が、装置内でより活発に⾏動していることがわか

図 6. 軌道図(1匹) N=12
図6.軌道図
(1匹)
N=12

-6-

6. 引用文献*

40

Greenspan, R. J., & Ferveur, J.-F. (2000).

35

COURTSHIP IN DROSOPHILA. Annual Review

orbital area (%)

30

of Genetics, 34(1), 205‒232.

25
20
15

Hidenobu Tsuzimura, et al. Drosophila for Science

10

Research

50-51sample(L)forStudents

Seitonorika

2019-1.

Retrieved on October 7, 2022 from

1sample(R) 5samples(L) 5samples(R)*P<0.01

Quinn, W. G., Harris, W. A., & Benzer, S. (1974).

図 7.
滞在率の平均値
図7.
滞在率の平均値(L : odor part, R : water part)

Conditioned Behavior in Drosophila melanogaster.

Proceedings of the National Academy of Sciences,

4. 展望

71(3), 708‒712.

ハエの学習能⼒が次世代に影響を与えるかど
うかを調べる。3-1 の実験結果を⽤いてハエが匂いの⽅へ向かうような装置を作る。ハエが餌を求Suh, G. S. B., Wong, A. M., Hergarden, A. C.,

めて匂いがある⽅へ向かう通路に微量な電流をWang, J. W., Simon, A. F., Benzer, S., Axel, R., &流し、匂いのある⽅へ⾏ってはいけないことを学

Anderson, D. J. (2004). A single population of

習させる実験を⾏う。学習させた個体同⼠を交配

olfactory sensory neurons mediates an innate

させて⽣まれたハエと、学習させていない個体同avoidance behaviour in Drosophila. Nature,

⼠を掛け合わせて⽣まれたハエに同じ実験を⾏

431(7010), 854‒859.

い、学習能⼒の差を測る。
Wiggin, T. D., Hsiao, Y., Liu, J. B., Huber, R., &Odor

Griffith, L. C. (2021). Rest Is Required to Learn
an Appetitively-Reinforced Operant Task in
Drosophila. Frontiers in Behavioral Neuroscience,

Water

15,

Start

681593.

https://doi.org/10.3389/fnbeh.2021.681593

図8. V字型装置

Damien Mercier, Yoshiko Tsuchimoto, Kazumi

5. 謝辞

Ohta,

この場を借りて、野⽣型のショウジョウバエを譲渡してくださった京都⼯芸繊維⼤学都丸教授、また、培地のレシピを譲渡してくださった⼤阪⼤
学⼤学院⽣命機能研究科甲斐教授には、厚く御礼申し上げます。

-7-

Hokto

Kazuma(2018).

Olfactory

Landmark-Based Communication in Interacting

Drosophila

Olfactory Influences on Behavior in Drosophila

G12 SSG Course
Ritsumeikan High School
JSSF 2023

January 19, 2024

Abstract
The purpose of this study is to better understand how changes in the environment such as smell
effect the behavior of Drosophila, and to determine how the parent’s ability to learn will affect thenext generation. Originally designed V-shaped tracks were made for this experiment to learn how
the behavior of flies changes due to the difference in odor of two substances. Drosophila placed ina fasting state were used. It was found that the best fasting time, the fasting time during which
Drosophila were most active in the track, was about 24 hours. An experiment was then conducted
to determine which substances Drosophila recognize as a food source due to their scent. For thisexperiment, mediums without yeast, propionic acid, and a combination of both were made fromthe normal medium. Normal medium in addition to modified different medium was placed at
different ends of the V-shaped track and five Drosophila were placed at the starting point. They
were observed for approximately 10 minutes. From observations made during this experiment, it
is suggested that Drosophila rely on the smell of yeast and propionic acid to get to the medium.
The results were confirmed by repeating the experiment using cottons dampened with water andyeast and propionic acid. When the effects of the different sexes on behavior in the apparatus were
examined, there was little effect. Therefor an examination of the differences in population density
revealed differences in movement within the apparatus.
Keywords: Drosophila,-8-

I. Introduction
Drosophila, among many other candidates, were used for this study. That is because they
are a model organism. Model organisms are organisms used to study universal life phenomena.
There are some reasons why they are used in studies. One reason is that their life cycle is shorter
than other organisms. The second reason is that the genome of Drosophila is open. In addition tothis, there are many mutant Drosophila. Because of this, it is possible to choose mutants of
Drosophila to use based on the research results.

Fig.1 Drosophila melanogaster (Oregon-R)

II. Materials and Method
In this experiment, a normal food agar medium, a carbon dioxide bottle, equipment madeby a 3D printer, a plastic sheet, an aspirator dish, and cotton were utilized. For the Condition
Experiment, normal food was placed at the side of the V-shaped track, followed by placing 5
flies in a fasting state at the starting point. The covered equipment was left in place for 10
minutes, and the scene was recorded to observe the flies' movement towards the normal food.
The Odor Experiments involved placing normal food and different types of food at the V-shaped
track's tip and dampening cotton with water, yeast, and propionic acid at each end of the track.
Five fasting flies were placed at the starting point, and the covered equipment was left for 10
minutes while recording the scene and measuring the flies' movement. Lastly, after the control
experiment, flies were narcotized, and their sex was determined using microscopy.

-9-III. Data Analysis
Pre-Experiment
In a preliminary experiment, when flies were placed at the center of the V-shaped track, asshown in Fig. 13 to observe the movement of the flies, many of them did not move at all or did
not go toward the medium, making it impossible to test whether the flies acted according to thesmell of the food (Table 4). Therefore, similar experiments were conducted with flies fasting for
1.5, 4, 5, 6.5, 9, and 24 hours, and we found that the flies moved toward the food most frequently
after the 24-hour fasting period (Table 3). Thus, individuals fasted for 24 hours were used insubsequent experiments.
The flies' conditions were tested to increase the accuracy of the experiment. First, a normal
medium was placed on one end of the V-shaped track. Then, 5 flies in a fasting state were placedat the start point. The equipment was then covered and left in place. A video recording of thescene was taken, and the number of flies that moved toward the normal medium was observed
for approximately 10 minutes. A good condition was defined as one where at least 70% of all theflies went towards the normal medium. If flies were in good condition, the experiment continued.

- 10 -

Odor Experiment 1 - Method
The purpose of this experiment is to know what odor from the normal medium isrecognized by flies for use in future control experiments. First, the normal medium was placed at
one end of the V-shaped track, and one of three different types of medium was placed at theother end. Then, 5 flies in a fasting state were placed at the start point. The equipment wascovered and left in place. A video recording of the scene was taken, and the number of flies thatmoved in either direction was observed for approximately 10 minutes.
Odor Experiment 1 – Results and Discussion
The number of flies that went towards the normal medium was higher when using the
medium without yeast than those without propionic acid. It might be that flies perceive propionicacid more easily, but it is difficult to generalize because the number of flies that stayed was
different. When the medium without yeast and propionic acid was used, more than 80% of theflies went toward the normal medium. This suggests that the substances flies recognize as a foodsource due to their scent were yeast and propionic acid.

- 11 -

Odor Experiment 2 – Method
To confirm the results from Experiment 1, an experiment using cotton was conducted.
First, cotton was cut and put at the ends of the V-shaped track. Then, the pieces of cotton werepermeated with either water or extracted yeast solution and propionic acid. Then, 5 Drosophila
in a fasting state were placed at the starting point. The equipment was covered and left. A video
recording of the scene was taken, and the number of flies that moved in either direction wasobserved for approximately 10 minutes.
Odor Experiment – Results and Discussion
75% of flies went toward the cotton with yeast and propionic acid. Only one fly went
toward the cotton with water. This result confirmed the findings from Experiment 1.

IV. Conclusion
Analysis on the Affect of Equipment
Similar results were obtained in the experiments conducted using the I-shaped track andthose conducted using the V-shaped track. Therefore, it was found that the difference between
the two types of equipment did not affect the behavior of the flies on the track. The V-shaped
track was used in this experiment since it was also used in the study by Timothy D. Wiggin et al.
Analysis on the Relationship Between the Sex of Flies and Their Movement
To determine the relation between sex and the movement of flies in the track, after thecontrol experiment, flies were narcotized and divided into male and female flies using- 12 -

microscopy. In Trials, ① and ③, the number of flies that went toward the normal medium wasalmost the same, but the number of males and females was the exact opposite. In Trials ② and⑤, there was little difference in the number of females and males. In other words, there was nodifference in behavior between the sexes.

Analysis on Population Density
To see if population density affects movement within the track, the following analysis was
conducted. The flies’ trajectories were taken in the tracks and divided into two parts (the odor
part and the water part), and the area of their trajectories was measured using ImageJ. Comparing- 13 -

the area with the odor and the area with water, it was found that the flies were more attracted tothe area with the odor. The results also show that the five individual flies in the experiment weremore active on the track than those with only one fly.

- 14 -

V. Future Research
To determine if the growing medium does not contain yeast and propionic acid but stillmoves toward the yeast and propionic acid odor, the following three processes will be carriedout: (1) Flies will be grown in the medium without yeast and propionic acid. (2) The same
experiment as Experiment 2 will be conducted using flies generated on the medium without yeast
and propionic acid. (3) They will be compared with those raised on a normal medium.
To determine if the behavior of the flies in Experiment 2 was due to odor by using mutants.
The same experiment as Experiment 2 will be conducted using mutants. The results from using
mutants will then be compared with those raised on a normal medium.

Finally, to determine how the parent’s ability to learn will affect the next generation flies
will be trained to head toward the odor. The next generation of trained flies will then be used todetermine how their behavior differs from the next generation of untrained flies.
VI. Acknowledgements
I would like to express my appreciation to Dr. Masatoshi Tomaru and the KYOTO
Drosophila Stock Center for providing Drosophila of the Oregon-R line for this research project.
I would like to take this opportunity to thank Professor Kai of the Graduate School of Frontier
Biosciences at Osaka University for providing the recipe for the culture medium.

- 15 -

VII. References
Greenspan, R. J., & Ferveur, J.-F. (2000). Courtship in Drosophila. Annual Review of Genetics,
34(1), 205–232. https://doi.org/10.1146/annurev.genet.34.1.205
Mercier, D., Tsuchimoto, Y., Ohta., K., & Kazama, H. (2018). Olfactory Landmark-Based
Communication in Interacting Drosophila. Current Biology, 28(16):2624-2631.
https://doi.org/10.1016/j.cub.2018.06.005
Tully, T., & Quinn, W. G. (1985). Classical conditioning and retention in normal and mutant
Drosophila melanogaster. Journal of Comparative Physiology A (1985) 157:267-277
Tsuzimura, H. et al. Drosophila for Science Research for Students Seitonorika 2019-1.
https://seitonorika.jp/honbunnengo/2019 論文本文/
Quinn, W. G., Harris, W. A., & Benzer, S. (1974). Conditioned Behavior in Drosophilamelanogaster. Proceedings of the National Academy of Sciences, 71(3), 708–712.
https://doi.org/10.1073/pnas.71.3.708- 16 -

Olfactory Influences
on Behavior in Drosophila

Ritsumeikan High School

ABSTRACTThe purpose of this study is to better understand how changes in the environment such as smell effect the behavior of Drosophila, and to determine how the parent’s ability to learn will affect the next generation. Originally designed Vshaped tracks were made for this experiment to learn how the behavior of flies changes due to the difference in odor of two substances. Drosophila placed in a fasting state were used. It was found that the best fasting time, the fastingtime during which Drosophila were most active in the track, was about 24 hours. An experiment was then conducted to determine which substances Drosophila recognize as a food source due to their scent. For this experiment,
mediums without yeast, propionic acid, and a combination of both were made from the normal medium. Normal medium in addition to modified different medium was placed at different ends of the V-shaped track and five Drosophila
were placed at the starting point. They were observed for approximately 10 minutes. From observations made during this experiment, it is suggested that Drosophila rely on the smell of yeast and propionic acid to get to the medium.
The results were confirmed by repeating the experiment using cottons dampened with water and yeast and propionic acid. When the effects of the different sexes on behavior in the apparatus were examined, there was little effect.
Therefor an examination of the differences in population density revealed differences in movement within the apparatus.

INTRODUCTION

EXPERIMENT 1 (Continued)

For this study, I decided to use Drosophila, among many other candidates.
That is because it is a model organism. Model organisms are organisms
used to study universal life phenomenon. There are some reasons why
they are used in studies. One reason is that their life cycle is shorter thanthat of other organisms. The second reason is that the genome of
Drosophila is open. In addition to this, there are many mutant Drosophila.
Because of this, it is possible to choose mutants of Drosophila to use
based on the results of this research.

RESULT and DISCUSSION
The number of flies that went towards the normal medium was higher
when using the medium without yeast than when using one without
propionic acid. It might that flies perceive propionic acid more easily, but
it is difficult to generalize because the number of flies that stayed weredifferent. When the medium without yeast and propionic acid was used,
more than 80% of the flies went towards the normal medium. Thissuggests that the substances flies recognize as a food source due to theirscent were yeast and propionic acid.

Fig.1 Drosophila melanogaster (Oregon-R)

MATERIAL

Fig.14 Photo of experiment

Table 5 Result of experiment (without propionic acid)

AGAR MEDIUMNORMAL MEDIUM
Table 1 Components of medium

NormalmediumTable 2 Components of agar medium

water (mL)270

agar powder (g)1yeast (g)10water (mL)50

corn flour (g)10rice bran (g)4glucose (g)20agar powder (g)1.3

propionic acid (mL)1.3butyl p-hydroxybenzoate/ethanol (mL)

1.3

Start

Fig.15 V-shaped track
Table 6 Result of experiment (without yeast)

Table 7 Result of experiment (without yeast and propionic acid)

EXPERIMENT 2
Fig.2 Normal medium

Fig.3 Agar medium

ODOR
METHOD
To confirm the results from Experiment 1, an experiment using cottons was conducted. First, cotton was cut andput at the ends of the V-shaped track. Then, the pieces of cotton were permeated with either water or extracted
yeast solution and propionic acid. Then, 5 Drosophila in a fasting state were placed at the starting point. The
equipment was covered and left. A video recording of the scene was taken and the number of flies that moved ineither direction was observed for approximately 10 minutes.

EQUIPMENT・Carbon dioxide bottle
・Cotton・Modified food・Equipment
・Plastic sheet・Dish・Aspirator

Modified
mediumRESULT and DISCUSSION
Fig.4 Carbon dioxide bottle

Fig.5 Cotton

Fig.6 Modified medium

Water

75% of flies went toward the cotton with yeast and propionic acid. Only one fly went
toward the cotton with water. This result confirmed the findings from Experiment 1.
Table 8 Result of experiment with cotton

Odor

Fig.8 Plastic coverStart

Fig.16 V-shaped track

ANALYSISNORMAL MEDIUMFirst, the materials (water, corn flour, sugar, yeast, agar powder) were measured,
mixed, and made into a liquid. Next, they were heated until boiling. Once boiling, themixture was heated over low heat for 15 minutes. After turning off the heat, thepropionic acid and butyl p-hydroxybenzoate/ethanol were added and mixed. The
mixture was then placed in test tubes and left overnight to decrease the humidity ofthe test tube.

POPULATION DENSITY

Fig.11 Making the medium

Flies

To see if population density affects movement within the track, the following analysis was conducted. The flies’
trajectories were taken in the tracks, divided into two parts (the odor part and the water part), and the area of theirtrajectories was measured using imageJ. Comparing the area with the odor and the area with water, it was foundthat the flies were more attracted to the area with the odor. The results also show that the five individuals in theexperiment were more active in the track than those in the experiment with only one individual.
*
40

odor

About 20 flies were placed in test tubes containing the medium. The environmental
conditions were managed to maintain temperatures under 23℃ with 12 hours of dark and 12
hours of light. After about two weeks, the next generation was born, and it was transferred toa new medium. Carbon dioxide was used as a means of transfer.

start

water

Fig.17 Orbital map (5 flies density) N=10

EQUIPMENT

orbital area (%)

Fig.7 Equipment

Fig.10 Aspirator

Fig.9 Dish

35
30
25
20
15
10
5

A blueprint for a track was drawn up using Tinkercad and printed out using a 3D
printer. Two types of equipment were made. A cover was made for the equipment
by cutting a piece of plastic sheet to fit the equipment. The cover was removable.

0-5

1sample(L)1sample(R)5samples(L)5samples(R)*P<0.01(L : odor part, R : water part)Fig.12 3D printed tracks

Fig.19 Average of destination stay rate

CONDITION

Fig.18 Orbital map (1 fly density) N=12First, flies that were metamorphosized were placed in the fasting state after two days. Subsequently, from among
these flies, active flies climbing up the test tube were chosen for use in experiments.

Ⅰ To determine if the growing medium does not contain yeast and propionic acid, but still moves toward to

PRE-EXPERIMENT

the yeast and propionic acid odor.
1. Flies will be grown in the medium without yeast and propionic acid.
2. The same experiment as Experiment 2 will be conducted using flies generated on the medium without
yeast and propionic acid.
3. They will be compared with those raised on normal medium.

CONTROLTo increase the accuracy of the experiment, the flies’ conditions were tested. First, normal medium
was placed one end of the V-shaped track. Then, 5 flies in a fasting state were placed at the start point.
The equipment was then covered and left in place. A video recording of the scene was taken and thenumber of flies that moved toward the normal medium was observed for approximately 10 minutes. A
good condition was defined as one in which at least 70% of all the flies went towards the normal
medium. If the flies were in a good condition, the experiment was continued.
Table 3 Result of the first control experiment

FUTURE PLAN

No
mediumⅡ To determine if the behavior of the flies in Experiment 2 was due to odor by using mutants.

Odor

1. The same experiment as Experiment 2 will be conducted using mutants.
2. They will be compared with those raised on normal medium.

Ⅲ To determine how the parent’s ability to learn will affect the next generation

Table 4 Result of the second control experiment
Normalmedium

Start
point

Fig.13 V-shaped track

EXPERIMENT 1ODORMETHOD
The purpose of this experiment is to know what odor from the normal medium is recognized by flies for use in
future control experiments. First, the normal medium was placed at one end of the V-shaped track, and one ofthree different types of medium were placed at the other end. Then, 5 flies in a fasting state were placed at the startpoint. The equipment was covered and left in place. A video recording of the scene was taken and the number offlies that moved in either direction was observed for approximately 10 minutes.

1. Flies will be trained to head in the direction of the odor.
2. The next generation of trained flies will be used to determine how their behavior
differs from the next generation of untrained flies.

Water

Start

Fig.20 V-shaped track

ACKNOWLEDGMENTS
I would like to take this opportunity to thank Dr. Masatoshi Tomaru of Kyoto Drosophila Stock Center for providing
the Drosophila Oregon-R line for this research project and Professor Kai of the Graduate School of Frontier
Biosciences at Osaka University for providing the recipe for the culture medium.

REFERENCES
Greenspan, R. J., & Ferveur, J.-F. (2000). COURTSHIP IN DROSOPHILA. Annual Review of Genetics, 34(1), 205–232.
Hidenobu Tsuzimura, et al. Drosophila for Science Research for Students Seitonorika 2019-1. Retrieved on October 7, 2022
Quinn, W. G., Harris, W. A., & Benzer, S. (1974). Conditioned Behavior in Drosophila melanogaster. Proceedings of the National
Academy of Sciences, 71(3), 708–712.
Wiggin, T. D., Hsiao, Y., Liu, J. B., Huber, R., & Griffith, L. C. (2021). Rest Is Required to Learn an Appetitively-Reinforced Operant
Task in Drosophila. Frontiers in Behavioral Neuroscience, 15, 681593.

カビの抑制に影響を及ぼす物質について

要旨
賞味期限を超えた食パンに生えたカビを見たことから,カビの発生の抑制に影響を与える物質に興味を持った。食パンと擦りおろしニンニクや練りわさびを容器に入れて一定期間，観察した結果，擦りおろしニンニクにはカビの抑制効果が認められた。現在,ニンニクの成分であるアリシンに着目し,様々な条件によりカビの抑制について研究をおこなっている。

1. 背景(手順 2) 3D プリンターでの台の作成

中学 3 年生の頃,賞味期限が切れた食パンはどのくらい日が経てばカビが生えてくるのか,生え

食パンとビーカーの大きさに対応させた台のないようにするにはどのような工夫が必要なのパーツを 3D プリンターで作成し,組み立てた(図食パンを利用1)。この台は,予備実験で使用していた厚紙で作して」という実験をおこなった。そのことがきっった土台が食パンの重さに耐えられず,不安定でかけとなり,カビの探究活動を続け,以前考察すあり,かつ食パンと土台に接着面があったことかることができなかった,カビの抑制の原因の解明

ら,食パンの全ての面が空気に触れるように柱をについて取り組むことにした。本研究の目的は,作った。また,食パンの形が安定するようにアル「食パンに生えるカビの抑制に影響を及ぼす物

ミホイルケースを入れるスペースを確保しなが質の解明」である。

ら 2 本足で台を立たせた。

2. 方法(手順 3) 組み立て

2－1. 試料(手順 1)の食パンを,(手順 2)で製作した台にか気になり,「カビの発生と抑制

本研究は,食パン(Pasco『超塾』5 スライス入り)

スタンプを押す時のように押し込み,食パンを手をカビの培地とし,サンプル(アメリカ産擦りおで触らないようにポリエチレン手袋を使い,組み

ろしニンニク,練りわさび,レモン)を利用して,立て,底面が 4 cm 程度のアルミホイルケースを小カビの発生の有無を確認した。

さくして,500 mL ビーカーの中に入れた(図 2)。
また,食パンと台がくっついたものの下の空間に

2－2. 実験方法

アルミホイルケースが収まるようにした(図 3)。

(手順 1) 培地の作成

そして,そのアルミホイルケースの中に様々なサ食パンを 1 スライス用意し，食パンの耳を除き，ンプルを入れた。

食パン本体に手が触れないように，ピンセットと果物ナイフを使い，6 つの正方形サイズの食パン(4 cm×4 cm)に切り分け，霧吹きで水を 2 回程度(約 3 mL)かけ，空気に 20 秒程度触れさせた。

- 18 -

間で遠心分離をおこない,上清液をとり,沈澱物を確認した。その沈澱物をさらにイオン交換水を用いて 100 mL で浸出したものを pH 4 に調整した。これらのことを 2 回繰り返し,沈澱物を細かく して いった 。最 終的に 抽出 できた 沈澱 物をPBS(リン酸緩衝液)10 mL に溶解し,他の雑菌が生えないようにするためにトルエンを 2 滴ほど落とし,これをアリイナーゼ酵素液とした。
制作したこれらの溶液をアリイン溶液 1 mL につきアリイナーゼ酵素液 0.5 mL を反応させ,アリ

図 1. 3D プリンターで制作した台シン溶液と推測できるものを調整した(図 4(a)〜(c))。

図 2. 密閉した容器(a) アリイン溶液(b) アリイナーゼ酵素液

ラップで密閉する

食パン

中にサンプル

アルミホイル(c) アリシン溶液

図 3. 模式図

図 4. アリシン溶液製作
各種調整溶液2－3. アリシン溶液の調整方法
アリシン溶液はニンニクから抽出ができるア
リイナーゼ酵素液をアリイン溶液に作用させて3. 結果と考察製作できる。まず,剥きニンニク 450 g を乾燥さ3－1. 実験 1

せ,粉末状にして,80％メタノールを用いて撹拌〈結果〉抽出を 24 時間×3 回おこなった。その後,真空ポサンプルには身近にある匂いのきつい物質でンプを利用して減圧濃縮をおこない,250 mL ほどある。レモン(生のレモンをくし切りしたもの),のアリイン溶液を製作した。

擦りおろしニンニク,練りわさび(チューブ)を使次に,ニンニクを 10 g 磨砕し,イオン交換水を用いて 100 mL で浸出した。それを 3000 rpm,2 分用し,これらをアルミホイルケースの中に入れ,
室温(25℃)で 2 週間観察をおこなった。

- 19 -

結果は以下の図 5〜8 のようになった。図 5,6 に擦りおろしニンニクと練りわさびについて,同

おいては,カビは生えており,図 7,8 においてはカじ実験を異なる時期で,同じ条件でいくつかおこ

ビの発生が抑制されていた。

なった。すると,2 週間後の食パンの様子は,また同じように一つもカビが生えていなかった。
これらのことから,「擦りおろしニンニク」と「練りわさび」にはカビの発生を抑制する効果があると示唆できる。
3－2. 実験 2〈結果〉

図 5. 何もなし

実験 1 の結果から,サンプルの状態を変化させ

図 6. レモンても,カビの発生の抑制効果は続くのかが気になり,状態を変化させやすいニンニクで実験をおこなうことにした。一つは,果物ナイフで内側に深さ 6 mm,長さ 7mm 程度の切り傷をいれたニンニクを使用し,もう一つは,ホットプレートで 5 分ほど熱を加えた擦りおろしニンニクを使用し,室温(25℃)で 2 週間観察をおこなった。
図 7. 擦りおろし
ニンニク

図 8. 練りわさび

結果は以下の図 9,10 のようになった。図 9,10 ともにカビが生えていた。

〈考察〉
擦りおろしニンニクと練りわさびを入れたビーカーの食パンは,他のものと同じ状況であったにも関わらず,一つもカビが生えていないことがわかった。また,レモンを入れた食パンは,異常な量のカビが生え,黄色くなっているのがわかった。
何も入れていない食パンには,緑色をした青カビが生えていた。今回の実験は匂いがカビの抑制に

図 9. 傷をつけた

影響を及ぼすのではないかと考え,おこなったもニンニクのであったため,レモンを入れた食パンにだけカビが生えたことには少し疑問を持った。レモンは

図 10. 熱を加えた
擦りおろし
ニンニク

〈考察〉

果物の中でクエン酸含有量が 1 番多いと知られて2 週間後の食パンの様子を見てみると,図 8 のいるので,生レモンの果実自体を置くのではなく,傷をつけたニンニクや,図 9 の熱を加えた擦りお

レモンを絞ってレモン汁の状態をサンプルとす

ろしニンニクは,擦りおろしたニンニクとは異なれば,カビを抑制できたのではないかと考える。

り,カビが生えていた。これは,図 11 のニンニク

この実験で一つもカビが生えていなかった擦の防カビ効果の仕組みが原因である。ニンニクにりおろしニンニクを入れたビーカーの食パンと,は,アリシンという『揮発性抗菌成分』が含まれて練りわさびを入れたビーカーの食パンは,引き続おり,その成分はアリインという無臭の非タンパき観察することにした。

ク質性アミノ酸が,ニンニクを擦りおろすことに- 20 -

よって発生するアリイナーゼという酵素によっ〈考察〉
2 週間後の食パンの様子を見てみると,アリシて活性化されてできるものである。
つまり,実験 2 では,傷をつけたニンニクは,擦ン溶液を入れたビーカーの食パンにはカビが一りおろしていないので,アリイナーゼが発生しなつも生えていなかった(図 13)。これはアリシンがかったため,アリインが活性化されず,また,熱を食パンに生えるカビに対して,揮発性抗菌成分と加えた擦りおろしニンニクは,熱によって成分がして反応したと示唆できる。また,ニンニクの上失活し,カビの抑制効果がなくなったからだと考清液を入れたビーカーの食パンにはカビが生えていたが,この上清液はアリイナーゼ酵素液を製作する際に取り出したものであるので,ニンニク

GSAC

から取り出したものであったとしても抗菌成分がほとんど含まれていないものであったため,カアリイン

ビの発生が抑制されなかったのだと考えられる。

アリイナーゼ

さらに,アリインについて詳しく調査した結果,
アリイン自体にも抗菌作用があることがわかっアリシンた。しかし,アリイナーゼによって活性化された

図11. ニンニクの防カビ効果の仕組み

アリシンと比べると,抗菌力は劣るものである。
現在,それらを比較するために,アリイン溶液のえられる。

みをサンプルとした実験をおこなっている。
3－3. 実験 3
4. 展望

〈結果〉
実験 2 の結果から,ニンニクの状態を変化させこれまでの実験を通して,ニンニクに含まれるるとカビが発生することがわかった。このことに揮発性抗菌成分であるアリシンがカビの発生の関して調査した結果,ニンニクのカビの抑制効果

抑制に影響を及ぼしているということがわかっには『揮発性抗菌成分』であるアリシンが関係した。しかし,今回のどの実験も室温(25℃)でおこていることがわかった。そこで,上記の 2-3 の方なっていたため,アリシンの耐熱性について探究

法でアリシン溶液の製作に取り掛かった。

できていないことがわかる。アリシンは高い反応製作したものをアリシン溶液と判断するため性 と低 い熱安 定性 がある こと が知ら れて いるにアリイナーゼ酵素液の製作途中で取り出した(Ref.4)。この先行研究から真空凍結乾燥ニンニ

ニンニクの上清液と比較し,室温(25℃)で 2 週間

クの抗菌活性は 80℃で 20 分以上加熱すると失活観察をおこなった。

し,これは生ニンニクでも同様の現象が起こることが認められている。
このことから,今回の実験で製作したアリシン

結果は以下の図の 12,13 のようになった。
図 12,13 ともにカビが生えていた。

溶液を,0℃,50℃,80℃,100℃の 4 通りで一定時間加熱し,カビの抑制効果が持続するのかを検証していく。また,アリシンの抑制効果には特有の匂いが影響していると考えられるので,温度変化によって,この匂いを取り除きつつ,カビの抑制を抑えつつ、機能する防腐剤を製作していこうと考えている。

図 12. ニンニクの上清液 図 13. アリシン溶液- 21 -

5. 参考文献
Ref.1
友山本敬男,望月恵美子,堀江正一,猪飼誉(1995)「にんにく製品中のアリイン,アリシ

ンの含量について」,山梨衛公研年報,p11-14
Ref.2

津野貞子

(1958)「ニンニク属植物の栄養的価値に関する研究：（XVI）ニンニク属植物中の Alliinase について」,ビタミン 14 巻,p659-664
Ref.3 ニンニクと健康(日本薬学会 環境・衛生部会)
URL
https://bukai.pharm.or.jp/bukai_kanei/topic
s/topics59.html
Ref.4 樋口智之,木村誠也 (2021)「様々な温度で加熱した真空凍結乾燥ニンニクにおける抗菌活性の耐熱性に関する研究」,日本冷凍空調学会
論文集 38 巻 3 号,p243-249- 22 -

Substances Affecting Mold Suppression

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
The objective of this research is to find the substances that affect the suppression of mold growing
on bread. The bread was placed in a container with lemon, grated garlic, and wasabi paste, all ofwhich had a strong odor, and observed for about two weeks. Later, focusing on allicin, acomponent of garlic, an experiment was conducted on mold suppression by comparing two garlic
samples. One sample contained a clove of garlic cut, and the other was grated, then heated. The
results showed that allicin, a volatile antimicrobial component in garlic, affected the inhibition ofmold growth. From there, the focus shifted to elucidating the mechanism of the inhibitory effectof allicin on mold. Alliin was extracted from American peeled garlic and added to an alliinase
enzyme solution to make an allicin solution. Future research should focus on the thermostabilityof allicin, concentrating on the variation of its inhibitory effect with temperature change.
Keywords: mold, growth suppression, lemon, garlic, wasabi, allicin- 23 -

I. Introduction
In the third grade of junior high school, curiosity arose about the duration it took for moldto grow on expired bread and the measures required to prevent mold growth. An experiment
titled "Mold Development and Control Using Bread" was conducted then. The experiment led toa desire to investigate mold further. The objective shifted to studying the causes of moldsuppression, an aspect that had not been explored before.
II. Materials and Method
Materials
One slice of bread, water, atomizer, aluminum foil, wrap, 500 mL beaker, lemon, grated
garlic, wasabi paste (tube), fruit knife, 3D printer, and polyethylene gloves were used.
MethodFirst, a slice of bread was prepared, and polyethylene gloves were worn to prevent directcontact with the bread. The bread was then cut into six squares, removing the crust. The squares
were sprayed with water using an atomizer twice and left to air for 20 seconds.
Second, parts of the platform corresponding to the size of the bread and beaker were madeusing a 3D printer and assembled (Fig. 1).
Third, the bread from the first step was pressed into the stand made in the second step as if
it was stamped, and then assembled using polyethylene gloves to prevent touching the bread withhands, and a small aluminum foil case with a base of about 4 cm was placed inside a 500 mL
beaker (Fig. 2). The aluminum foil case was placed in the space under the beaker (Fig. 3).
Various samples were placed in the aluminum foil case.

- 24 -

III. Data Analysis
Experiment 1
Lemon (fresh lemon cut into wedges), grated garlic, and wasabi paste (from a tube) wasused. These were placed in aluminum foil and observed at room temperature (25°C) for two
weeks. The results are shown in Figure 4.

- 25 -

Experiment 2
This experiment focused on whether the inhibitory effect of mold development persists
when the state is changed. Another experiment was conducted with garlic, which can easilychange its state. The results are shown in Figures 5 and 6.

Experiment 3
From the results of Experiment 2, it was found that allicin, a "volatile antimicrobial
ingredient," was responsible for the inhibitory effect of garlic on mold, so an allicin solution wasmade.

To make the alliin solution, 450 g of American peeled garlic was dried, powdered, andstirred in 80% methanol for 24 h, This was done three times. The extract was then concentrated
under reduced pressure using a vacuum pump. For the alliinase enzyme solution, 10 grams ofgarlic were ground, repeatedly centrifuged at 3000 rpm for 2 minutes, and the supernatant- 26 -

solution was collected. The sediment was finely divided, the pH was adjusted to 4, and after thethird centrifugation, 10 mL of PBS was dissolved in the sediment, and two drops of toluene wereadded to prevent bacterial contamination. The allicin solution was created using 0.5 mL ofalliinase enzyme solution per 1 mL of alliin solution. The following experiment was conductedto confirm this. After two weeks, the bread in the beaker with the allicin solution did not haveany mold growth (Figure 10).

IV. Discussion
Experiment 1
From the results of Experiment 1, it was found that none of the bread in the beaker withgrated garlic and wasabi paste had mold, even though they were under the same conditions as theothers. The bread in the beaker with grated garlic and the bread in the beaker with wasabi paste,
both of which had no mold growth in this experiment, continued to be monitored. The same
experiment was conducted with grated garlic and kneaded horseradish at different times andunder the same conditions. Two weeks later, the bread was again free of any mold. These results
suggest that grated garlic and wasabi paste had an inhibitory effect on mold growth.

- 27 -

Experiment 2
After two weeks, the bread was found to be moldy, as was seen in Fig. 5 and Fig. 6. This is
u

h

ch

s

g

c’s

-mold effect. Garlic contains allicin, a "volatile

antimicrobial ingredient" formed when alliin is activated by the alliinase enzyme, produced when
g

c sg

.As

GSA

s h

u

g

c’s

-mold effect. In other words, inExperiment 2, the cut garlic was not abraded, so alliin was not activated because alliinase was
not generated. The grated garlic that was heated was inactivated by the heat, so it lost its moldinhibitory effect.
Experiment 3
It is thought that the garlic supernatant contained little or no antimicrobial components.
V. Conclusions
In these experiments, it was discovered that grated garlic and kneaded horseradish act as
substances inhibiting mold. Additionally, it was observed that without rubbing it down, the moldinhibitory effect cannot be attained for garlic. Furthermore, allicin, a volatile antimicrobial
component in garlic, was successfully extracted.
VI. Future Research
Through previous experiments, it was found that allicin, a volatile antimicrobial ingredientin garlic, affected the inhibition of mold growth. However, since all the experiments were
c

uc

u

(25℃) h hs bc

h s not been explored.

Future research should find the thermostability of antimicrobial activity in garlic. Furthermore, toproduce a preservative that does not give off any other odor using garlic by reducing the uniqueodor of allicin while maintaining its mold suppression effect.

- 28 -

VII. Acknowledgements
I would like to take this opportunity to thank Mr. Satoshi Yanagiya, Dr. Mie Ichikawa, and
Dr. Noriyuki Matsuura for their accurate advice.
VIII. References
Haiping Wang, et al. (2014). Influence of pH, concentration and light on stability of allicin ingarlic (Allium sativum L.) aqueous extract as measured by UPLC. Journal of the Scienceof Food and Agriculture 2015. 1838-1844
津野貞子 [Tuno Sadako] . (1958). ニンニク属植物の栄養的価値に関する研究:(ⅩⅥ)ニン
ニク属植物中の Alliinase について [Studies on the Nutritional Value of Garlic Plants:(XVI) Alliinase in Garlic Plants], ビタミン 14 巻 [Vitamins, vol. 14.], p659-664
山本敬男 [Yamamoto Takeo] et al, (1995), にんにく製品中のアリイン,アリシンの含量について [Alliin and Allicin Content in Garlic Products], 山梨衛公研年報 [Annual Report of
the Yamanashi Institute of Public Health], p11-14

- 29
66 -

Substances Affecting
Mold Suppression

Ritsumeikan High School

Abstract
The objective of this research is to find the substances that affect the suppression of mold growing on bread. The bread was placed in a container with lemon, grated garlic, and wasabi
paste, all of which have a strong odor, and observed for about two weeks. Later, focusing on allicin, a component of garlic, an experiment was conducted on mold suppression bycomparing two samples of garlic. One sample contained a clove a garlic that was cut and the other was grated, then heated. The results showed that allicin, a volatile antimicrobial
component in garlic, had an effect on the inhibition of mold growth. From there, the focus shifted to elucidating the mechanism of the inhibitory effect of allicin on mold. Alliin was extracted
from American peeled garlic an added to an alliinase enzyme solution to make an allicin solution. Future research should focus on the thermostability of allicin, concentrating on thevariation of its inhibitory effect with temperature change.

Introduction

Experiment 2

When I was in the third grade of junior high school, I was curious about how long it took formold to grow on expired bread and what kind of measures were needed to prevent moldfrom growing, so I conducted an experiment titled "Mold Development and Control Using
Bread”. This experiment led me to want to investigate mold further. I wanted to study thecauses of mold suppression, something which I had not been able to do before.

〈Sample〉This experiment focused on whether the inhibitory effect of mold development
persists when the state is changed. Another experiment was conducted withgarlic, which can easily to change its state.
〈Result & Discussion〉

Materials & Method

GSAC〈Materials〉
one slice of bread, water, atomizer, aluminum foil, wrap, 500 mL beaker, lemon, grated
garlic, wasabi paste (tube), fruit knife, 3D printer, and polyethylene gloves.

AlliinAlliinase〈Method〉【STEP 1】A slice of bread was prepared, and polyethylene gloves were worn to prevent
direct contact with the bread. The bread was then cut into six squares,
removing the crust. The squares were sprayed with water using an atomizer
twice and left to air for 20 seconds.
【STEP 2】Parts of the platform corresponding to the size of the bread and beaker weremade using a 3D printer and assembled (Fig. 1).
【STEP 3】The bread from【STEP 1】was pressed into the stand made in【STEP 2】asif it were stamped, and then assembled using polyethylene gloves to prevent
touching the bread with hands, and a small aluminum foil case with a base ofabout 4 cm was placed inside a 500 mL beaker (Fig. 2). The aluminum foilcase was placed in the space under the beaker (Fig. 3). Various samples wereplaced in the aluminum f o i l c a s e .

Wrap
Bread

Mold Determination :Mold Determination :Fig.5 A clove of garlicwith small cuts

Fig.6 Heated grated garlic

AllicinFig.7 Mechanism ofgarlic's anti-mold effect

After two weeks, the bread was found to be moldy, as was seen in Fig. 5 and Fig. 6. This isdue to the mechanism of garlic’s anti-mold effect. Garlic contains allicin, a "volatile
antimicrobial ingredient" that is formed when alliin is activated by the alliinase enzyme,
which is produced when garlic is grated. Also, GSAC is the foundation of garlic’s anti-moldeffect. In other words, in Experiment 2, the cut garlic was not abraded, so alliin was not
activated because alliinase was not generated, and the grated garlic that was heated wasinactivated by the heat, so it lost its mold inhibitory effect.

Experiment 3
From the results of Experiment 2, it was found that allicin, a "volatile antimicrobial
ingredient," was responsible for the inhibitory effect of garlic on mold, so an allicin solution
was made.

SampleAluminum foil

Fig.1 3D printed platform

Fig.2 Sealed container

Fig.3 Schematic diagram

Alliinase enzyme solution

Allicin solution

Fig.8 Produce of Allicin solution

Experiment 1〈Sample〉 Lemon (Fresh lemon cut into wedges), Grated garlic, Wasabi paste(from a tube)
These were placed in aluminum foil and observed at room temperature (25°C) for
two weeks.
〈Result & Discussion〉(a)

Alliin solution

To make the alliin solution, 450 g of American peeled garlic was dried, powdered, andstirred in 80% methanol for 24h, This was done three times. The extract was thenconcentrated under reduced pressure using a vacuum pump. For the alliinase enzyme
solution, 10 g of garlic was ground, centrifuged repeatedly at 3000 rpm for 2 min, thesupernatant solution was taken, the sediment was finely divided, adjusted to pH 4, and after
the third centrifugation, 10 mL of PBS was dissolved in the sediment and 2 drops of toluene
was added to keep bacteria out. The allicin solution was created using 0.5 mL of alliinase
enzyme solution per 1 mL of alliin solution. The following experiment was conducted toconfirm this.
〈Result & Discussion〉
After two weeks, the bread in the
beaker with the allicin solution did nothave any mold growth (Fig. 10). It isthought that the garlic supernatant was
one that contained little or no
antimicrobial components.

(b)

Mold Determination :Mold Determination : ◯Fig.9 Garlic supernatantFig.10 Allicin solution

Mold Determination :Mold Determination :Future Plan

(c)

(d)

Through previous experiments, it was found that allicin, a volatile antimicrobial ingredient ingarlic, had an effect on the inhibition of mold growth. However, since all the experiments
were conducted at room temperature (25℃), the thermostability of allicin has not been
explored. Future research should elucidate the thermostability of antimicrobial activity ingarlic using Ref.1 as a prior research.

Mold Determination : ◯Mold Determination : ◯◎Ref.1 樋口智之 [Higuchi Tomoyuki], 木村誠也 [Kimura Seiya]. (2021). 様々な温度で加熱した真空凍結乾燥ニンニクにおける抗菌活性の耐熱性に関する研究 [Heated atvarious temperatures. Study on the thermostability of antimicrobial activity invacuum freeze-dried garlic], 日本冷凍空調学会論文集38巻3号 [Transactions of theJapan Society of Refrigerating and Air Conditioning Engineers, Vol. 38, No. 3],
p243-249

References
Fig.4 Bread after two weeks 〔 (a) Nothing (b) Lemon (c) Grated garlic (d) Wasabi paste 〕
Mold Determination : Moldy‥‥ , Completely mold free‥‥◯

From the results of Experiment 1, it was found that none of the bread in the beaker withgrated garlic and wasabi paste had mold, even though they were under the same conditions
as the others. The bread in the beaker with grated garlic and the bread in the beaker withwasabi paste, both of which had no mold growth in this experiment, were continued to bemonitored. The same experiment was conducted with grated garlic and kneaded
horseradish at different times and under the same conditions. Two weeks later, the bread
was again free of any mold. These results suggest that grated garlic and wasabi paste had
an inhibitory effect on mold growth.

◎Ref.2 津野貞子 [Tuno Sadako] . (1958). ニンニク属植物の栄養的価値に関する研究:(ⅩⅥ)
ニンニク属植物中のAlliinaseについて [Studies on the Nutritional Value of Garlic
Plants: (XVI) Alliinase in Garlic Plants], ビタミン14巻 [Vitamins, vol. 14.], p659-664◎Ref.3 山本敬男 [Yamamoto Takeo] et al, (1995), にんにく製品中のアリイン,アリシンの含量について [Alliin and Allicin Content in Garlic Products], 山梨衛公研年報 [Annual
Report of the Yamanashi Institute of Public Health], p11-14

アントシアニンを用いた日焼け止めクリームの開発

要旨
この研究は３つの問題を解決することを目的としている。1 つ目は、日焼け止めが及ぼす人体への影響である。2 つ目は、日焼け止めが及ぼす海の生物への影響である。3 つ目は、世界のワイン
産業での食品廃棄の問題である。日焼け止めは日常的に多くの人々の体に塗布されており、その成分は皮膚に吸収され、そこには人体に有害な化学物質、たとえば、オキシベンゾンなどが含まれている。また、人々が日焼け止めを塗った後に海に入ると、それらの化学物質が水中に溶けてサンゴや海の生き物に悪影響を及ぼすことも分かっている。一方で、世界のワイン産業では年間 1,200 万
トン近くのブドウの搾りかすが廃棄されている、しかし、ブドウの皮にはアントシアニンという色素が豊富に含まれている。アントシアニンは光防御特性があることで知られている。そこで我々は、ブドウの皮のアントシアニンを用いて、食品廃棄の削減ができ、人体に無害で、海の生き物にも悪影響がない、という三つの利点のある日焼け止めを作ろうと考えた。またこの研究はシンガポールの National Junior College との国際共同課題研究である。

1. 背景

たとえば、ナスでは太陽の光が当たらないヘタ

市販の日焼け止めにはオキシベンゾンやパラの下の部分は青紫色が少し薄くなっている

ベンなどの有害な成分が含まれている。世界の（ref.2）。このことから、アントシアニンの光

ワイン産業では、毎年 1,200 万トンものブドウの吸収の特性を利用することで、より安全な日焼

搾りかすが廃棄されている、ブドウの皮にはアけ止めクリームを作製できると考えられる。こントシアニンが豊富で、搾りかすの質量の 50％の研究では、ブドウに含まれるアントシアニンを占める。ブドウのアントシアニンはデルフィを使った日焼け止めを開発することでブドウのニジン、シアニジン、ペチュニジン、ペオニジ

アントシアニンの紫外線防御特性を調査した。

ン、マルビジンの 3-o-モノグルコシドである（ref.1）。アントシアニンは植物細胞の細胞質

2. 方法

内のフラボノイド経路を経由して生成される水

2－1. ブドウのアントシアニンからの日焼け止め

溶性の色素で、植物の赤、青、紫の色の原因とクリームの作製（日本）なる。
光は光合成の主なエネルギー源であるが、強2−1−1. アントシアニンの抽出

い光の条件下ではアントシアニン細胞の液胞はブドウ(Vitis vinifera)の皮を剥き、皮を液体

強い光による光阻害及び抗酸化反応から葉緑体

窒素(-169℃)で凍結し、乳棒とすり鉢を用いてを保護し、過剰な高エネルギー粒子を吸収する

細かく砕き、アントシアニンの抽出率を高めよ

ことによって光による化合物の異化反応を防ぐ。

うとした。これをバイオフリーザーで-20℃で 11- 31 -

日 間保 管した 後、 すりつ ぶし たブド ウの 皮とンスイルミネーター(Ultra-Lum, Inc., UVB-10,

0.1%の HCl を質量比 2.5:1 の割合で混合し、ホッ300 nm)の上に、4.5 cm × 6.5 cm の長方形の穴

トスターラーを使用し、プレート温度を 50℃にを開けたアルミホイルを、穴が紫外線照射範囲

設定し、2.5 時間熱した。その後冷蔵庫(4℃)での上になるように敷き、その穴の上に、スライ保管した。

ドガラス 2 枚の間にセロハンテープ 3 枚分の厚さの日焼け止めクリームを挟んだもの（①とする）

2−1−2. アントシアニンの精製と、スライドガラスを、日焼け止めクリームを2−1−1 の液体を桐山ろうと（ADVANTEC No.2）

挟まずに 2 枚重ねたもの（②とする）を UV トラ

で吸引濾過し、その濾液を遠心分離機で 4000

ンスイルミネーターの上に置いた。酸化チタン、rpm で 5 分間、6000 rpm で 5 分間、8000 rpm でメチレンブルー、イオン交換水の混合液 5 mL を

30 分間遠心分離し,沈殿物を取り除いた。

バイアルに注ぎ、それを①と②の上に 3 個ずつ置いた。そして UV トランスイルミネーターから紫2−1−3. アントシアニンの定量

外線を 5 分間、10 分間、15 分間照射し、メチレ

ブドウの皮からアントシアニンを抽出した後pH Differential 法によりアントシアニンの定量

ンブルーの溶液の青色がどれ程脱色されたかを確認した。

を行った。300 μL のアントシアニン溶液を 3 mLの pH 1,4,7 の緩衝液とそれぞれ混合し、それらを石英キュベットに入れ、紫外可視分光光度計で測定した。
2－2. クリームとの混合
2-2-1. 水相の調整
アントシアニン抽出液 6 g,グリセリン 20 g を
イオン交換水 10 mL と混合し、ホットスターラー
で 80℃、3 分間加熱した。
2−2−2. 油相の調整
ステアリン酸 20 g とセチルアルコール 4 g を混合し、ホットスターラーで 80℃、10 分間加熱した。

図 1. 紫外線照射の実験の様子

2−2−3. 相の混合

2−4．2−3 で用いたメチレンブルーの溶液の濃度

水相と油相をホットスターラーで 80℃、30 分の定量

間撹拌しながら混合し、pH 試験紙で pH が 8 にな

2−3 で用いた溶液をイオン交換水で 2 倍希釈しるまで、少量のトリエタノールアミンを加えた。

たものの吸光度を、紫外可視分光光度計を用いて測定し、それをランベルト・ベールの法則にしたがって、メチレンブルーの溶液のモル濃度

2-3. 日焼け止めの紫外線防護の効果の測定
メチレンブルーの水溶液（濃度は結果 2-4 参照）に、二酸化チタン 0.05 g を加えた。ミニ UV トラ- 32 -

を定量した。
ランベルト・ベールの法則
𝐴 = 𝜀𝑐𝑙
A=メチレンブルーの吸光度ε=665 nm でのメチレンブルーのモル吸光係数91000 L/(mol・cm) (Nishizaka et al. 1993)
c=メチレンブルーのモル濃度
l=セルの長さ(1 cm)
図 3. pH 1 に緩衝化されたアントシアニン溶液の吸収スペクトル

3. 結果と考察
3－1. 緩衝化されたブドウのアントシアニンの抽出液についてアントシアニンは pH によって構造が変化し、その構造に応じて光の吸収波が変化する。図 3～7 の通り、pH 1,4,7 で吸収スペクトルが変化することから、抽出液がアントシアニンであると判断した。pH 1,4,7 に緩衝化されたアントシア
ニン溶液の pH 値はそれぞれ 0.4, 3.7, 6.7 であった。 pH 1.1, 3.0, 5.0 における最大吸収波長の文献値はそれぞれ 521.5 nm, 523.0 nm, 532.0

図 4. pH 4 に緩衝化されたアントシアニン溶液

nm である。

の吸収スペクトル

図 2. 遠心分離した後のブドウのアントシアニン
抽出液
表 1. それぞれの緩衝化されたアントシアニン溶
液の pH 値
緩衝液
pH 1 に緩衝化されたアントシアニン
pH 4 に緩衝化されたアントシアニン
pH 7 に緩衝化されたアントシアニン

pH 値
0.4
3.7
6.7

図 5. pH 7 に緩衝化されたアントシアニン溶液の吸収スペクトル
また、紫外可視分光光度計を用いて紫外線の吸収スペクトルも読み取った。読み取った結果
吸光度が高すぎた原因としては、測定溶液の濃度が高すぎて正確に測定できなかったことが考えられる。

- 33 -

加えた。

図 6. pH 1 に緩衝化されたアントシアニン溶液の紫外領域の吸収スペクトル

図９. ブドウのアントシアニンを用いて作製した
日焼け止めクリーム3－3. 日焼け止めクリームの紫外線防護の効果について
プラスチック容器に入れたメチレンブルーと二酸化チタンの混合液を、紫外線を照射しなかったもの、スライドガラスに挟んだ日焼け止め
図 7. pH 4 に緩衝化されたアントシアニン溶液のクリームの下から紫外線照射機で 5 分、10 分、

紫外領域の吸収スペクトル15 分紫外線を照射したもの、スライドガラス 2 枚の間に何も挟まずに 5 分、10 分、15 分紫外線を照射したものの 7 つの溶液のメチレンブルーの脱色の違いは次の図 10 のようになった。

図 10. (左から)メチレンブルーと二酸化チタン
図 8. pH 7 に緩衝化されたアントシアニン溶液のの混合液に紫外線を照射しなかったもの、日焼

紫外領域の吸収スペクトル

け止めを挟んだスライドガラスの上で 5 分、10 分、15 分紫外線を照射したもの、日焼け止めを挟ま

3－2. ブドウのアントシアニンを用いて作製しずにスライドガラスの上で 5 分、10 分、15 分紫た日焼け止めについて

外線を照射したもの

pH 試験紙で日焼け止めクリームの pH を読みとり、pH が 8 になるまでトリエタノールアミンを

図 10 のように、メチレンブルーの溶液は、スラ- 34 -

イドガラスの上に日焼け止めを挟まずに紫外線

4-3. SPF の測定を照射したものに比べて、日焼け止めを挟んでクリームを測り、100 mL メスフラスコに移し、照射したものの方が、脱色の度合いが小さくな

エタノールで希釈する。その溶液 1 mL を 10 mLっている。

メスフラスコに移し、エタノールで量を調節す

このことから、この日焼け止めクリームは紫外る。吸光度の測定は、290 ～ 320 nm の範囲で 5線防護の特性があると言える。

m 間隔で行う。アントシアニンの吸光度値を得た
後、式により SPF を算出する。

2-4. 実験 2-3 で用いたメチレンブルーの溶液のSPF(Spectrometry) = CF × 23EE(λ) × I(λ)

濃度について× Abs(λ)

実験 2-3 に用いたメチレンブルーの溶液を 2 倍希釈したものの吸光度は 665 nm で 0.27 であっ

CF＝10（補正係数）,た。これを𝐴 = 𝜀𝑐𝑙に代入して、算出した濃度を 2

EE(λ)=波長 λ における放射線の発赤効果,

倍すると、メチレンブルーのモル濃度は、5.89

I(λ) = 波長 λ における太陽光の強度,

mol/L ということが分かった。

Abs(λ) = 波長 λ の吸光度

0.3

4-4.耐水性の測定

-6

×10

Absorbance

実用的な日焼け止クリームを作製するため、
0.2

日焼け止めクリームの耐水性を検証する。

0.1

5. 謝辞
実験方法やデータ分析などこの国際共同課題
研究で有益なアドバイスをくださった National

0
300

400

500

600

700

Junior College の Shan Shan Lee 先生にこの場

Wavelength (nm)を借りて厚く御礼申し上げます。また、立命館
図 11. 実験 2-3 で用いたメチレンブルーの溶液

高校の市川美恵博士には生物の分野において実を 2 倍希釈したものの吸収スペクトル験方法について貴重なアドバイスを沢山していただき、紫外線照射機の貸与や紫外可視分光光

4. 今後の予定

度計の使い方、グラフの分析の仕方等を指導し4-1. 対照実験てくださり、とても感謝しております。松浦紀

2-4.の実験を、アントシアニンの抽出液を入之博士には化学的な視点からグラフの分析の指れていないクリーム、SPF30 の市販の日焼け止め

導と吸引濾過機の貸与をしていただき、深く感でも同様の実験を行い、実験結果で得られた紫謝しております。そしてシンガポールとの国際

外線カットの効果が本当にアントシアニンの抽

共同課題研究をするにあたり、Joseph Greenleaf

出液によるものなのかを検証し、また市販の日先生、廣松光一郎先生に研修を引率していただ

焼け止めとの性能を比較する。

きました。深く感謝しております。そして国際課題研究を担当してくださった弓削亨先生に感4-2.均質性の確認

謝申し上げます。共同研究者である齊藤玲澄さ

クリームの滑らかさ（粗粒度）と凝集を顕微鏡で分析する。

ん、脇長世莉さん、Mo Thant Cin さん、Ricthika
Suradren さん、Jocelyn Winata さんには、この
約 7 ヶ月間共にディスカッションや実験を行い、- 35 -

何度も助けられました。ありがとうございまし5. 西 坂 剛 , 円 入 寛 子 , 竹 野 哲 , 大 倉 一 郎(1993)「メチレンブルーを光増感剤とた。
最後に、本論文を執筆するにあたり協力してくださったすべての方に厚くお礼申し上げます。

する光化学療法に関する研究」,日本化学会誌,867-873.
https://doi.org/10.1246/nikkashi.1993.

6. 引用文献867

1. Costa, E., Cosme, F., Jordão, A.M.,
Mendes-Faia,

A.(2014,January),

Anthocyanin profile and antioxidant
activity

from

24

grape

varieties

cultivated in two Portuguese wine
regions. JournalInternationaldesSciences de la Vigne et du Vin.48(1).
51-62.
DOI: 10.20870/oeno-one.2014.48.1.1661
2. アントシアニン | 成分情報. (2023, May
17).

わ

か

さ

の

秘

密

.

URL:https://himitsu.wakasa.jp/content
s/anthocyanin/ アクセス 2023/12/20
3. Lozovskaya, T., Brenner-Weiss, G.,
Franzreb,

M.,

Nusser,M.(2012,September). Recovery of Anthocyaninsfrom Grape Pomace Extract (Pinot Noir)Using Magnetic Particles Based on
Alcohol). Cellulose

Poly(Vinyl

Chemistry

andTechnology, 46(7–8),

427–433.
https://www.cellulosechemtechnol.ro/p
df/CCT7-8(2012)/p.427-433.pdf
4. 壺阪美智子,前野佳奈美(1995).「ぶどうアントシアニン色素―食品加工上の特徴について―」,甲子園短期大学紀要,13,1-11.
https://doi.org/10.24699/koshient.13.
0_1- 36 -

Exploring the Photoprotective Capabilities of Anthocyanin

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
The theme of this research focused on three problems. First, the effects of sunscreen on the humanbody. Second, the effects of sunscreen on marine life. Third, finding a use for food waste from thewine industry. Sunscreen is applied daily to many people's bodies, and the ingredients in sunscreen
get absorbed by the skin into the bloodstream. Some of these ingredients may contain harmful
compounds. Also, if we enter the sea after applying sunscreen, some of it can come off in the water,
causing harm to marine life. Meanwhile, pomace, the dry or pulpy residue of grapes consisting ofgrape seeds and skins, is something that the global wine industry produces close to 12 million tonsof each year. It is typically discarded during wine production; however, research on grape pomace
has revealed that it is rich in anthocyanins. Anthocyanins have photoprotective capabilities.
Therefore, if it were possible to make sunscreen out of grape skins, it would solve these threeproblems. This research was done as part of an International Collaborative Research Project with
National Junior College in Singapore.
Keywords: sunscreen, pomace, grapes, anthocyanin, photoprotection- 37 -

I. Introduction
In conventional sunscreen, there are a lot of harmful ingredients. In the global wine
industry, 12 million tons of grape pomace is produced every year. The skins of grapes, high inanthocyanins, make up 50% of this pomace by weight. According to Costa et al. (2014), “Grapeanthocyanins are the 3-O-monoglucosides of delphinidin, cyanidin, petunidin, peonidin, andmalvidin.” Anthocyanins are water-soluble pigments produced via the flavonoid pathway in thecytoplasm of the colored plant cell. They are responsible for the deep red, blue, and purple
pigments found in plants.
Light is the main source of energy for photosynthesis. However, under strong light
conditions, plants may capture more light than photo utilization capacity. So, plants develop theirsystems to protect themselves from these photooxidative stresses, and anthocyanin is a primeexample. In the case of eggplants, most of the color is deep purple, but the bottom of the calyx,
which is not exposed to sunlight, has a slightly lighter blue-purple color (Anthocyanin, 2023).
Thus, anthocyanins may be a safer alternative for photo-protection. The UV-inhibiting propertiesof anthocyanins found in grapes and the optimal proportion for maximum sun protection areinvestigated and compared in this research.
II. Materials and Method
1. Making Sunscreen from Grape Skin
1.1: Extraction of Anthocyanin
First, the grapes (Vitis vinifera) were peeled to remove their skins. Then they were frozen
using liquid nitrogen. Finally, they were finely ground using a mortar and pestle, allowing for thecomplete rupture of cells and, thus, very high anthocyanin extraction rates. The prepared raw
material was kept at -20 °C until extraction.

- 38 -

For extraction, the grape skins were mixed with 0.1% HCl at a ratio of 2.5:1, W/W. The
resulting mass was heated in a water bath at 50°C for 2 hours using a hot stirrer. After that, it
was stored in a refrigerator.
1.2: Purification of Anthocyanin
The crude extract was filtered using a suction filter. After that, it was centrifuged at 4000
pm for 5 minutes, 6000 rpm for 5 minutes, and 8000 rpm for 30 minutes. There was a precipitate,
which was removed. The main factors considered were the purity, yield, operating components,
and production cycle of the target substance.
1.3 Quantification of Anthocyanin
After obtaining the anthocyanin extract from the grape pomace, quantification of theconcentration of anthocyanin was done through the pH Differential Method. 300 L ofanthocyanin solutions was added to 3 mL of buffers. Each of the pH 1, pH 4, and pH 7 bufferedanthocyanin solutions were placed in a cuvette and then into a UV-vis spectrophotometer to readthe absorbance of UV light.
2. Mixing with Creme
2.1 Aqueous Phase Preparation
6g of anthocyanin extract 20g of Glycerin were dissolved in deionized 10 mL Water to beheated to 80°C for 3 minutes.
2.2 Oil Phase Preparation
20g of Stearic acid and 4g of Cetyl alcohol were mixed and heated at 80°C for 10 minutes.

- 39 -

2.3 Mixing Phase
Oil phase was added to the aqueous phase at 80°C with continuous stirring for 30 minutes
till a uniform emulsion was formed. Then, triethanolamine was added till the pH value became 8.
The pH value was measured using a pH test paper.
3. Measurement of the Photoprotective Capabilities of Sunscreen
35g of methylene blue solution (see results for concentration) was mixed with 0.05g oftitanium dioxide. A piece of aluminum foil with a 4.5 cm × 6.5 cm rectangular hole was placed
on top of a Mini Size UV Transilluminator (Ultra-Lum, Inc., UVB-10, 300 nm) with the hole
above the UV irradiation area. Over the hole, place sunscreen with the sickness of three sheets ofcellophane tape between two glass slides (referred as ①), and then stack two slide glasses
without sandwiching the sunscreen (referred as ②) was placed. A mixture of titanium dioxideand methylene blue solution was poured into six vials (5 mL each), and three vials each wereplaced on top of ① and ②. UV light was then irradiated from the UV transilluminator for 5, 10,
and 15 minutes to check how much the methylene blue solution was decolorized. Experiments
were conducted in the dark.

Fig.1 Setup of UV irradiation- 40 -

4. Quantification of the Concentration of Methylene Blue Solution Used in Experiment 3
The absorbance of methylene blue solution used in experiment 4 diluted twice with ionexchanged water was measured using an UV-vis spectrophotometer, and the molar concentrationof the methylene blue solution was calculated using the Beer-Lambert Law, represented by theformula: 𝐴 = 𝜀𝑐𝑙
A = absorbance of methylene blue solution;
ε = molar extinction coefficient of methylene blue at 665 nm (91,000 L/(mol・cm))(Nishizaka et al., 1993);
c = molar concentration of methylene blue solution; l = cell length (1 cm)
III. Result and Discussion
About the Buffered Anthocyanin Solution
Anthocyanins change their structure depending on the pH value, and the wavelength oflight absorbs changes depending on the structure. Therefore, since the absorption spectrum
changed at pH 1, 4, 7, it was determined that the extracted liquid was anthocyanin. The pH
values of pH 1, 4, and 7 buffered anthocyanin solutions were 0.4, 3.7, and 6.7.
According to reference 3, the maximum absorption wavelength at pH 1.1, pH 3.0, and pH
5.0 was 521.5 nm, 523.0 nm, and 532.0 nm.

Table.1 pH value of each buffered anthocyanin solution

Solution

pH value

pH1 buffered anthocyanin

0.4

pH 4 buffered anthocyanin

3.7

pH 7 buffered anthocyanin

6.7- 41 -

Fig.2 Centrifuged liquidFig.3 Graphs showing the absorption spectrum of pH 1, 4, and 7 buffered anthocyanin solutions

Fig.4 Graphs showing the UV absorption spectrum of pH 1, 4, and 7 buffered anthocyanin solutions

A possible cause of the absorbance value of UV light being too high is that theconcentration of the measurement solution was too high and could not be measured accurately.
About the Sunscreen Made with Anthocyanins Extracted from Grape Skin
The pH value of the sunscreen was read using a pH test paper and it was 8.

Fig.5 Sunscreen made with anthocyanins
extracted from grape skin

The Photoprotective Capabilities of Sunscreen
The mixture of methylene blue and titanium dioxide in a viral (5 mL each) was exposed to
UV light for 5, 10, and 15 minutes with a UV irradiator from under a sunscreen sandwiched- 42 -

between two glass slides, without anything between the two glass slides, and no UV light. The
difference in methylene blue decolorization of the seven solutions is shown in Figure 6 below.

Fig.6 (From left to right) Methylene blue solution without UV irradiation, UV irradiated for 5, 10, 15
minutes from under two glass slides with sunscreen in between, and UV irradiated for 5, 10, 15
minutes from under two glass slides without sunscreen in between

As shown in Figure 6, the degree of discoloration of the methylene blue solution is smallerwhen it is exposed to UV light from below with a sunscreen between the glass slides than when
it is exposed to UV light from below without the sunscreen between the glass slides. From thisresult, it can be said that this sunscreen has photoprotective capabilities.
The Concentration of Methylene Blue Solution Used in Experiment 3
The absorbance of the solution of methylene blue used in experiment 4, diluted twofoldwith ion-exchange water, was 0.27 at 665 nm. By substituting this absorbance into the formulaand doubling the calculated concentration, the molar concentration of methylene blue was foundto be 5.89 × 10-6 mol/L.

Fig.7 The absorption spectrum of solution of methylene blue used inexperiment 4 after it was diluted twofold with ion-exchange water- 43 -

IV. Conclusion
In conclusion, sunscreen prototypes containing anthocyanin extracts of grapes weresuccessfully formulated, with significant photoprotective effects observed when tested for withthe set up using methylene blue-titanium dioxide solution.
V. Future ResearchControl Experiment
The same experiment as in experiment 3 should be conducted with a cream without
anthocyanin extract and a commercial sunscreen with SPF 30 to verify whether thephotoprotective effect obtained in the experiment is really due to the anthocyanin extract and tocompare its performance with that of the commercial sunscreen.
Homogeneity Test
Creams will be analyzed under a microscope for grittiness and aggregations.
SPF Determination
To determine the SPF of the cream, it should be transferred to a 100 mL volumetric flask
and diluted to volume with ethanol. Then, 1 mL aliquot is to be transferred to a 10 mL
volumetric flask, and the volume is to be adjusted with ethanol. The absorption data is to beobtained in the range of 290-320 nm every 5 m interval. After obtaining absorbance values ofanthocyanins, SPF is to be calculated using the following formula:
SPF(Spectrometry) = CF × 23EE(λ) × I(2) × Abs(λ)
CF = 10 (Correction Factor); EE(λ) = Erythemogenic effect of radiation at wavelength λ;I(λ) = Intensity of solar light at wavelength λ; Abs(λ) = Absorbance of wavelength λWater Resistance Test
Creams should also be tested in terms of their water resistance to determine their viability.

- 44 -

VI. Acknowledgements
I would like to take this opportunity to thank Dr. Shan Shan Lee of National Junior College
for his useful advice on experimental methods and data analysis for this international joint
research project. I am also incredibly grateful to Dr. Mie Ichikawa of Ritsumeikan High Schoolfor providing me with a lot of valuable advice on experimental methods in the field of biology,
and for lending me a UV irradiation machine and teaching me how to use a UV-visible
spectrophotometer and how to analyze graphs. I am deeply grateful to Dr. Noriyuki Matsuura for
his guidance on graph analysis from a chemical perspective and for lending me a suction
filtration machine. I would like to extend my thanks to Mr. Joseph Greenleaf and Mr. Koichiro
Hiromatsu for leading the training for the International Collaborative Research Project with
Singapore. I would also like to express my gratitude to Mr. Toru Yuge, who oversaw theInternational Collaborative Research Project. I would also like to thank Ms. Ann Flanagan for
their guidance in writing my dissertation in English. Finally, I would like to thank mycollaborators, Ms. Asumi Saito, Ms. Seri Wakinaga, Ms. Mo Thant Cin, Ms. Ricthika Suradren,
and Ms. Jocelyn Winata, who helped me many times during our discussions and experiments
together for the past seven months. Thank you very much.

- 45 -

VII. References
アントシアニン [Anthocyanin]. (2023, May 17). わかさの秘密 [Wakasa no himitsu].

https://himitsu.wakasa.jp/contents/anthocyanin/
Costa, E., Cosme, F., Jordão, A.M., Mendes-Faia, A. (2014, January). Anthocyanin profile andantioxidant activity from 24 grape varieties cultivated in two Portuguese wine regions.
Journal International Des Sciences De La Vigne Et Du Vin. 48(1):51-62. DOI:
10.20870/oeno-one.2014.48.1.1661
Lozovskaya, T., Brenner-Weiss, G., Franzreb, M., Nusser, M. (2012, September). Recovery ofanthocyanins from grape pomace extract (pinot noir) using magnetic particles based onpoly (vinyl alcohol). Cellulose Chemistry and Technology. 46(7). 427-433.
https://www.cellulosechemtechnol.ro/pdf/CCT7-8(2012)/p.427-433.pdf
西坂 剛, 円入 寛子, 竹野 哲, 大倉 一郎 [Nishizaka, T., Ennu, H., Takeno, T., Okura, I.]. メチレンブル
ーを光増感剤とする光化学療法に関する研究 [Photodynamic Therapy with Methylene Blue as
Photosensitizer]. 日本化学会誌（化学と工業化学）[Journal of the Chemical Society of Japan(Chemistry and Industrial Chemistry)]. 1993 巻 7 号 p. 867-873 [Vol 1993 No 7 p. 867-873]

https://doi.org/10.1246/nikkashi.1993.867
壺阪 美智子, 前野 佳奈美 [Tsubosaka, M., & Maeno, K.]. (1995). ぶどうアントシアニン色素―
食品加工上の特徴について― [Anthocyanin Pigments of Grapes - Characteristics in Food

Processing-]. 甲子園短期大学紀要 [Journal of Koushien Junior College]. 13 巻 p. 1-11 [Vol13 p. 1-11]. https://doi.org/10.24699/koshient.13.0_1- 46 -

Exploring the Photoprotective Capabilities
of Anthocyanin
Ritsumeikan High School
Abstract
The theme of this research focused on three problems. First, the effects of sunscreen on the human body. Second, the effects of sunscreen on marine life. Third, finding a use for food waste from the wine
industry. Sunscreen is applied daily to many people’s bodies, and the ingredients in sunscreen get absorbed by the skin into the bloodstream. Some of these ingredients may contain harmful compounds.
Also, if we enter the sea after applying sunscreen, some of it can come off in the water causing harm to marine life. Whereas, pomace, the dry or pulpy residue of grapes consisting of grape seeds andskins, is something that the global wine industry produces close to 12 million tons of each year. It is typically discarded during wine production, however, research on grape pomace has revealed that it isrich in anthocyanins. Anthocyanins have photoprotective capabilities. Therefore, if it were possible to make sunscreen out of grape skins, it would solve these three problems. Since the types of grapes
available in Japan and Singapore are different, grapes available in each country were used to investigate whether the effectiveness of sunscreen changes depending on the type of grape. To makesunscreen that solves the food waste problem, while containing little to no chemicals, aloe vera is also used in the cream.

First, the grapes were peeled to remove their skins (Fig.1), Then they were frozen using liquid
nitrogen. Finally, they were finely ground using a mortar and pestle (Fig.2). This allowed for thecomplete rupture of cells and thus very high anthocyanin extraction rates.
The prepared raw material was kept at -20℃ until extraction. After that, it was frozen by liquid
nitrogen and then was ground.
For extraction, the grape skins were mixed with 0.1% HCl at a ratio of 2.5:1, W/W(Fig.3). The
resulting mass was heated in a water bath at 50℃ for 2 hours using a hot stirrer. After that, it wasstored in a refrigerator.

After obtaining the anthocyanin extract from the grape pomace, quantification of theconcentration of anthocyanin was done through the pH Differential Method. 300 μL of
anthocyanin solutions was added to 3 ml of buffers. Each of the pH 1, pH 4, and pH 7 bufferedanthocyanin solutions were placed in a cuvette and then into a UV-vis spectrophotometer.
Table 1 pH value of each buffered anthocyanin solution

Fig.12 Buffered anthocyanin solutions(left: pH 1, middle: pH 4, right: pH 7)

Solution

pH valuePH 1 bufferedanthocyanin

0.4

PH 4 buffered
anythocyanin

3.7

PH 7 bufferedanthocyanin

6.7

0.25

1.6

0.35

1.4

0.3

0.2

0.25

1.2
1
0.8
0.6
0.4

AbsorbanceExperiment 1: Extraction of Anthocyanin

Experiment 3: Quantification of
Anthocyanin

AbsorbanceIn conventional sunscreen, there are a lot of harmful ingredients. In the global wine industry, 12
million tons of grape pomace is produced every year. The skins of grapes, which are high inanthocyanins, make up 50% of this pomace by weight. Anthocyanins are water-soluble pigments
produced via the flavonoid pathway in the cytoplasm of the colored plant cell. They are
responsible for the deep red, blue and purple pigments found in plants.
Light is the main source of energy for photosynthesis. However, under strong light conditions,plants may capture more light than for photoutilisation capacity. So plants develop their own
systems to protect themselves from these photooxidative stress and anthocyanin is a primeexample of this. Thus, anthocyanins may be a safer alternative for photo-protection. We will be
investigating and comparing the UV-inhibiting properties of anthocyanins found in grapes, and the
optimal proportion for maximum sun protection.

AbsorbanceIntroduction

0.15
0.1

0.2
0.15
0.1
0.05
0

0.05

-0.05 400

0.2
0

0
400

500

600

700

800

900

pH 1 buffer

500

-0.1
400

1000

500

600

700

800

900

600

700

800

900

1000

Wavelength(nm)1000

Wavelength(nm)Wavelength(nm)pH 4 buffer

pH 1 bufffered anthocyanin solution

Graph 1

pH 4 buffered anthocyanin solution

pH 7 buffer

Graph 2

pH 7 buffered anthocyanin solution

Graph 3

Fig.13 Graph 1, 2, 3 : Absorption spectrum of pH 1, 4, 7 buffer and pH 1, 4, 7 buffered anthocyanin solutions

Anthocyanins change their structure depending on the pH value, and the wavelength of lightabsorbs changes depending on the structure. Therefore, since the absorption spectrum changed at
pH 1, 4, 7, it was determined that the extracted liquid was anthocyanin. The pH values of pH 1, 4
and 7 buffered anthocyanin solutions was 0.4, 3.7, and 6.7.
According to the reference 3, the maximum absorption wavelength at pH 1.1, pH 3.0, pH 5.0 was
521.5 nm, 523.0 nm, 532.0 nm.
5

5

2.5

4.5

4.5
4

4

2

Fig.3 Mixed with 0.1% HCl

3
2.5
2
1.5

Experiment 2: Purification of Anthocyanin
The crude extract was filtered using a suction filter. After that, it was centrifuged at 4000 rpm for
5 minutes; 6000 rpm for 5 minutes; and 8000 rpm for 30 minutes.
There was a precipitate, so it was removed.
The main factors considered were the purity, yield, operating components, and production cycleof the target substance.

AbsorbanceFig.2. Frozen using liquid nitrogen

3.5

AbsorbanceFig.1 Peeled grapes

Absorbance

3.5
1.5
1

3
2.5
2
1.5

1

0.5

1

0.5

0.5

0

0
190

240

290

340

390

0
190

240

290

Wavelength(nm)pH1 buffer

pH0.4 anthocyanin solution

340

390

190

240

Wavelength(nm)pH 4 buffer

Graph 4

pH 4 anthcyanin solution

Graph 5

290

340

390

Wavelength(nm)pH 7 buffer

pH 7 anthocyanin solution

Graph 6

Fig.14 Graph 4, 5, 6 : UV Absorption spectrum of pH 1, 4, 7 buffer and pH 1, 4, 7 buffered anthocyanin solutions

The absorbance of UV light was read using a UV-vis spectrophotometer. A possible cause of theabsorbance value being too high is that the concentration of the measurement solution was toohigh and could not be measured accurately.

Sunscreen Prototypes
The extracted anthocyanin solution was mixed withglycerin and white petrolatum at a ratio of 1:1, weightby weight. When it is mixed with white petrolatum, it
becomes sticky, and when it is mixed with glycerin, it
becomes liquid, so neither is the best ingredient forsunscreen.
Fig.4 Suction filter

Fig.5 Suction filtering

Fig.6 Filtered liquid

Fig.7 Filtered liquid

Fig.15 Mixed with White Petrolatum Fig.16 Mixed with glycerin

Future Plan

Fig.8 Centrifuge

Fig.9 Centrifuge

Fig.10 Centrifuged liquid

Fig.11 Precipitate

References
1. Tatiana lozovskaya, gerald brenner-weiss, matthias franzreb, michael nusser. (n.d.). RECOVERY
OF ANTHOCYANINS FROM GRAPE POMACE EXTRACT (PINOT NOIR) USING MAGNETICPARTICLES BASED ON POLY(VINYL ALCOHOL). https://www.cellulosechemtechnol.ro/pdf/CCT78(2012)/p.427-433.pdf
2. 南光芹香，米田美月(Serika Nankou, Mitsuki Yoneda)(n.d.).日焼け止めの効果向上~アントシアニンを用いて~ [mproving theEffectiveness of Sunscreen ~ Using Anthocyanins ~].
https://kozuosaka.jp/cms/wcontent/uploads/2021/11/858b87c695beb40985c28664e977c30.p
df
3. Tsubosaka, M., & Maeno, K. (1995). Anthocyanin Pigments of Grapes 一 Characteristics in Food
Processing一. Journal of Koushien Junior College, 13, 1–11.
https://doi.org/https://doi.org/10.24699/koshient.13.0_1

Experiments to be done in the future are Experiments 4,5,6, and 7.
[Experiment 4: Make it mildly acidic]
A strong acid has a higher preventative power, so it must be made a weak acid while maintainingthat power. Because if it remains a strong acid, it cannot be applied to the skin.
[Experiment 5: Test the viability as sunblock]
Anthocyanins are chemical compounds, so they may decompose at high temperatures. To be a
viable sunblock it needs to remain heat stable under a temperature at which people apply
sunscreen. It is necessary to consider whether the effectiveness of sunscreen can be maintained
and what to do if it cannot be maintained.
[Experiment 6: Mix with aloe vera]
Aloe vera cream will be used to make a creamy sunscreen. Aloe vera cream is naturally derived, so
it has no negative effects on people or the environment.
[Experiment 7: With ready-made]The Experiment 6 mixture and ready-made products will be tested to see how much UV protection
they provide.

Acknowledgment
We would like to take this opportunity to thank Ms. Shan Shan Lee at National JuniorCollege in Singapore, Dr. Mie Ichikawa and Mr. Toru Yuge at Ritsumeikan High School for
mentoring us during this collaborative research and providing useful advice.

抹茶を用いた水溶液中の銅(Ⅱ)イオンの捕集除去実験

要旨
抹茶は茶葉を砕いたもので、日本の伝統的な飲み物である。 抹茶にはポリフェノール、タンニン、
アミノ酸、カフェインなどが含まれおり、抹茶の成分のおおよそ 10%はタンニン酸である。 タンニンの構造にはベンゼン環が含まれており、ベンゼン環に直接結合したヒドロキシ基は金属イオンに配位することができる。 合成樹脂であるフェノール樹脂は、フェノールとホルマリンを組み合わせることで得られることが知られている。 この技術を適用すると、フェノールの代わりにタンニンが金属イオンとの結合を利用して水から重金属イオンを除去できる可能性がある。 そこで、抹茶とタンニン酸を使って水中の金属イオンの除去を試みた。
私たちは抹茶、タンニン酸を使い、水中の重金属イオンの除去を実験した。また、抹茶、タンニン酸をホルマリンを用いて高分子化した際の効果も実験した。これらの実験結果からホルマリン処理をする前の抹茶とタンニン酸でも十分に水中の銅イオンを除去できた。しかし、ホルマリン処理をした後のタンニン酸は少し除去率が増えたが期待していたほどの結果は得られなかった。また、ホルマリン処理後の抹茶は固くて砕ききれていなかったため予想よりも低い除去効率となった。ホルマリン処理をする際には、温度と時間が全てのタンニン酸と抹茶を反応させるために重要なことが分かった。
たりしているため重金属イオンは一般的に水処

1. 背景
重金属は自然界に低濃度で存在しており、その理プロセスで取り除くことが難しい。このような一部は私たちが生きていくために必要な必須元

問題は地域や状況によって異なるが一般的に、重素として知られている。しかし、湖沼などの環境

金属イオンの水中存在は環境および健康に対す

2+

る潜在的なリスクがある。そのため、環境水中の2+

水中に銅(Ⅱ)イオン Cu 、水銀(Ⅱ)イオン Hg 、
2+

鉛(Ⅱ)イオン Pb などの重金属イオンが排出され重金属イオンを簡易かつ迅速に分離することは、

ると、水質汚染につながる。水中に存在する場合、重要なことであると考えた。

人や生物に摂取される可能性があり、健康被害を様々な植物に含まれるポリフェノールは、古く引き起こすことがある。たとえば、鉛やカドミウ

から食品、染色剤、塗料、樹脂などに利用されてムは神経系や腎臓に悪影響を与えることが知らきた。ポリフェノールの分子構造中にはフェノーれている。また、水中存在は水生生物の成長や繁ル性のヒドロキシ基-OH があるため、重金属イオ

殖に悪影響を与えることもある。重金属が食物連ンに配位することができる。そのため、ポリフェ鎖を通じて上位の生物に蓄積されることもあり、ノールは重金属イオンの捕集剤として利用され生態系全体に広がる可能性がある。そして、産業てきた。先行研究では、コーヒー、グァバ、紅茶

廃水や鉱業などの産業活動によって水中に放出などのポリフェノールを含む食品を使って水中された重金属イオンは、地域の水源や水道水に含の銅(Ⅱ)イオンの捕集除去実験を行い、除去できまれる可能性があり、飲料水や農業用水の品質がることがすでに示されている。

悪化すると考えられる。水中の重金属イオンが固そこで本実験では、天然素材を利用して水中の体物質や混濁物と結合して分散されたり、溶存し重金属イオンを除去する方法を考えた。この実験- 48 -

は日本の伝統的な飲み物である抹茶に焦点を当

2－2. 水中の銅(Ⅱ)イオンの捕集除去てた。 抹茶には約 10％の抹茶ポリフェノールが次にホルマリン処理する前の抹茶とタンニン含まれている。抹茶ポリフェノールには、ベンゼ酸とホルマリン処理後の抹茶とタンニン酸を使ン環に直接結合したヒドロキシ基が含まれていい水溶液中の銅イオンの補修除去実験を行った。

る。 プロトンを含むヒドロキシレートは、ヒドロ

抹茶に含まれる水溶性のポリフェノールは，分キシ基から除去され、金属イオンに配位すること

子量が比較的小さいため銅(Ⅱ)イオンに結合すができます。 また、抹茶に含まれており、構造がる。しかし、生じた錯イオンは水に溶けやすく，似ているタンニン酸も使って実験を行った。 ま

水中から銅(Ⅱ)イオンを捕集除去することは難

た、抹茶を高分子化することで、さらに多くの重しいと予想される。そこで高校化学で学習したフ金属イオンを吸着できるのではないかと考えた。

ェノールとホルマリンの反応から，メチレン基によって架橋されたプラスチックである「フェノール樹脂」の合成反応を応用することで水溶性のポ
リフェノールを重合できないかと考えた。

図 1, 抹茶ポリフェノールの構造と金属イオンの配位
図 3, フェノール樹脂の合成スキーム

2. 方法
2－1. ホルマリン処理
この実験では抹茶、タンニン酸それぞれにホル

銅（Ⅱ）イオンを含む水溶液(模擬廃液)に抹茶

マリン処理を行った。抹茶は市販の京都府産のもまたはホルマリン処理抹茶を加え、30 分間撹拌しの使用した。タンニン酸はポリフェノールの一種て金属イオンを除去した。ビーカーに一定量の銅であるため、比較実験として使った。ナス型フラ(Ⅱ)イオンを含む水溶液、抹茶 0.25 g、ヨウ化カ

スコに抹茶 1.0 g に対してホルマリン(37％ホル

リウム 0.60 g をいれて、スターラーで 30 分攪拌

ムアルデヒド水溶液)5.0 mL、0.10 mol/L 硫酸

した。水中の銅(Ⅱ)イオンの適量はヨウ素滴定を20.0 mL を加え、60℃の水浴中で２時間撹拌した。

使って行った。ビュレットを用いて 0.1 mol/L のホルマリン処理後、アスピレーターでろ過した。

チオ硫酸ナトリウムを加え、滴定した。この操作

沈殿物をイオン交換水 100 mL で洗浄し、遠心分は複数回行った。ホルマリン処理後の抹茶、ホル離をすることで上澄み液を取り除き、数回行うこマリン処理前のタンニン酸、ホルマリン処理後のとで未反応のホルマリンを取り除いた。その後、タンニン酸についても同様の条件で除去率を調

自然乾燥させて乳鉢で粉砕した。 実験は、抹茶

べた。抹茶を用いるときは液体を一度吸引ろ過し1.0 g と 10.0 g、タンニン酸 1.0 g と 5.0 g を各てから滴定を行った。なぜなら抹茶の色が濃く、1 回ずつ行った。

ヨウ素滴定の色の変化がわからないからである。
私たちは，ポリフェノールが高分子化すると水に不溶な固体となって結合した銅(Ⅱ)イオンは濾過によって物理的に容易に取り除くことがきると言う仮説を立てた。

図 2, 攪拌

図 3, 洗浄後- 49 -

質量が小さく、ほとんどホルマリンで重合できた。
10.0 g の抹茶と 5.0 g のタンニン酸は質量が大きく、1.0 g の抹茶とタンニン酸よりも長時間反応させたが、すべての抹茶とタンニン酸を重合させることはできなかった。そのため、未反応の抹茶やタンニン酸は洗い流され、抹茶やタンニン酸

図 4, 濾過前後、滴定後の色の変化の 1.0 g よりも質量が大幅に減少したと考察した。
これより、質量を大きくすると重合させるための条件が難しくなると考えられる。

図 5, 実験手順
図 7, 抹茶+HCHO

図 8, タンニン酸+HCHO

3. 結果と考察
3－1. ホルマリン処理

3－2. 水中の銅(Ⅱ)イオンの捕集除去得られたホルマリン処理抹茶の色は暗褐色で、ホルマリン処理タンニン酸は薄い褐色であった。

図 9, 水中の銅(Ⅱ)イオンの質量
このグラフは、ヨウ素滴定により算出した、抹茶とタンニン酸による金属イオン除去後の水溶

図 6, ホルマリン処理前後の質量

液中の銅(Ⅱ)イオンの物質量を示している。

このグラフは、ホルマリン処理前の抹茶とタン
ニン酸の質量と、ホルマリン処理後の抹茶とタン

Na₂S₂O₃aq[mol/L]×drop volume/1000[L]=Amountof copper(Ⅱ) ion [mol]ニン酸の質量を示している。抹茶は 1.0 g と 10.0
g、タンニン酸は 1.0 g と 5.0 g を 1 回ずつホル

この式を使用して水溶液中の銅(Ⅱ)イオンの量

マリン処理したものでる。

を測定した。左から銅(Ⅱ)イオンのみ、抹茶、ホ

グラフからわかるように、いずれの質量もホルマリン処理前よりホルマリン処理後の方が小さ

ルマリン処理後の抹茶、タンニン酸、ホルマリン
処理後のタンニン酸である。

くなっている。抹茶 1.0 g とタンニン酸 5.0 g は- 50 -

捕集除去剤として抹茶を用いたときの銅(Ⅱ)
イオンの除去効率は 82%で最も高い割合で銅(Ⅱ)

その理由は、ホルマリン処理後に抹茶が十分に粉砕されなかったからであると考える。
この実験から、抹茶とタンニン酸は水から金属イオンを除去していることがわかった。一方でホルマリン処理抹茶を用いたときの除去効率は 59%

イオンを除去できることがわかった。

で、ホルマリン処理をして高分子化することで逆私たちの将来の実験の予定はホルマリン処理に大きく除去率が低下していて、私たちの仮説、で抹茶とタンニン酸の量が減らないように攪拌

抹茶を高分子化することで、さらに多くの重金属

時間を長くする予定だ。水中の銅(Ⅱ)イオンの捕

イオンを吸着できるのではないか、に反した結果

集除去の将来のプランはホルマリン処理前後のになった。その理由は、ホルマリン処理前の抹茶

抹茶の表面積の違いを、顕微鏡的な粉末分布を測の手触りはさらさらしていたのに対して、ホルマ定し計算することで比較することである。また、リン処理後の抹茶の手触りは十分に粉砕されな粉末を使用すると有効表面積を維持することがかったためざらざらしていた。このことから、ホ困難だったため、表面積の差を少なくするために、

ルマリン処理後の抹茶は砕けず粒子が大きく、ホ

粉末抹茶の代わりに茶葉を使用したい。

ルマリン処理前の抹茶に比べて表面積が小さく、天然素材を重金属イオンの除去剤としてうま除去効率が悪かったため、ホルマリン処理前のもく利用することができれば、廃棄物の再利用につのよりも除去率が悪くなったと考えられる。

ながるのではないかと考える。また、ポリフェノ

ポリフェノールと比較のために実験したタンールだけでなくタンニンでも重金属イオンを除ニン酸で実験すると、タンニン酸は 33%、ホルマ

去できることがわかった。これにより、タンニン

リン処理タンニン酸は 59%となり、タンニン酸はを含むほかのものでも除去剤に使用できるのでホルマリン処理し、高分子化させることで除去率はないかと考える。

が上がったことから、抹茶とタンニン酸ではホルマリン処理の前後で逆の結果になった。
抹茶とタンニン酸を比べてみると、抹茶の方が除去率がタンニン酸よりも高くなっている。

5. 謝辞
的確な助言をくださった松浦紀之先生、柳谷賢志
先生、市川美恵先生、そしてゼータ電位を測定していただき、分析に関する助言と援助をいただいた立命館大学生命科学部応用科学科の松川雄太
教授に厚く御礼を申し上げます。
また、執筆の過程でお世話になったすべての先生

図 10, 粉砕前抹茶方に感謝の意を表したいと思います。

図 11, 粉砕前タンニン酸

6. 引用文献

4. 展望
この実験の目的は、天然素材を用いて水中の金属イオンを除去することであった。この研究の仮説は、ホルマリン処理による高分子化によって金属イオンの捕集除去率が高まるというものであった。しかし、この仮説はタンニン酸では証明できたが、抹茶を使った結果は予想と違った。

1.後藤哲久, 堀江秀樹, 大関由紀, 増田英昭,藁．化学成分から見た市販緑茶の品
科二郎（1994）
質. 茶業研究報告, 1994(80), 23-28.
https://doi.org/10.5979/cha.1994.80_23.
2.木村優, 山下博美, 駒田順子（1986）．緑茶を- 51 -

吸着材として用いる水中の各種金属類の捕集除去法. 分析化学, 35(4), 400-405.
https://doi.org/10.2116/bunsekikagaku.35.4_
400.
3.木村優 (1992). 生物質と環境化学：緑茶を用いる水中の金属イオンの捕集除去(<特集>話題を探る>).
https://doi.org/10.20665/kakyoshi.40.5_- 52 -Collecting and Removing Heavy Metal Ions in Water Using Matcha

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
Matcha is made from crushed tea leaves and is a traditional Japanese drink. It contains tannins,amino acids, and caffeine, with 10% of its components being tannic acid. The structure of tannin
includes a benzene ring, and the hydroxy group directly attached to this ring can bind to metal ions.
It is known that phenol resin, a synthetic resin, is obtained by combining phenol with formalin.
Building on this technique, using tannins instead of phenols could facilitate the removal of heavy
metal ions from water through their binding properties. Therefore, the experiment used matcha
and tannic acid to remove metal ions from water. First, formalin treatment was applied for thepolymerization of both matcha and tannic acid. The experiment showed that substances with asmaller mass polymerized effectively, but those with larger masses were not fully formalized andwere washed away with water, resulting in a reduced powder yield. Next, iodometric titration, aquantitative method for measuring copper (II) ions, was used to determine their concentration. It
was found that both matcha and tannic acid, even before formalin treatment, adsorbed copper (II)ions effectively. However, the adsorption capacity of tannic acid improved after formalin treatment,
whereas matcha performed better before the treatment. This difference is attributed to the clumpingof matcha post-formalin treatment, which made it difficult to crush.
Keywords: matcha, tannic acid, heavy metal removal, polymerization, adsorption- 53 -

I. Introduction
Heavy metals are found in low concentrations in nature, and some of them are known asessential elements necessary for survival. However, when heavy metal ions are present inenvironmental water sources such as lakes and ponds, they negatively affect human health andecosystems due to their harmful effects. Previous studies have already shown that it can beremoved with coffee husks.
Therefore, this experiment studied a method to remove heavy metal ions from water using
natural materials. This experiment focused on matcha, a traditional Japanese drink. Matcha
contains about 10% matcha polyphenols. Matcha polyphenols contain a hydroxy group attacheddirectly to the benzene ring. Hydroxylates with a proton removed from the hydroxy group cancoordinate with metal ions. Using this property, we tried to collect and remove heavy metal ionsfrom water. The tannic acid in matcha is also used. In this study, the research team wondered if it
could adsorb even more heavy metal ions by making matcha a polymer.
II. Materials and Method
Experiment 1: Formalin Treatment
In this experiment, commercially available matcha from Kyoto Prefecture and tannic acid(a type of polyphenol) were treated with formalin. For this, 1.0 g of matcha was mixed with 5.0
mL of formalin and 20.0 mL of 0.10 mol/L sulfuric acid in a 100 mL eggplant-shaped flask. The
mixture was stirred at 60°C for 2 hours. Post-treatment, the matcha was filtered to remove
formalin, washed with 100 mL of ion-exchanged water, air-dried, and ground with a mortar andpestle. This process was repeated with two different quantities of matcha (1.0 g and 10 g) andtannic acid (1.0 g and 5.0 g).

- 54 -

Fig.1 Matcha mixture being stirred at 60oC

Fig.2 Washed matcha mixture

Experiment 2: Removal of Metal Ions in Water
This experiment evaluated the ability of matcha and tannic acid, both pre-and postformalin treatment, to remove copper ions from an aqueous solution. 0.25g of formalin-treatedmatcha powder was stirred in a copper (II) ion solution for 30 minutes, followed by the additionof 0.60g of potassium iodide. Sodium thiosulfate was then titrated into the solution, but due tomatcha's dark color, titration results were indistinct. To address this, suction filtration with Celite
was performed before titration to dilute the color. The copper removal rate was calculated using
the formula: Na₂S₂O₃ [mol/L] × drop volume / 1000 [L]. The removal rates of matcha and tannic
acid, both with and without formalin treatment, were compared under similar conditions.

Fig.3 Aqueous solution containing copper (II)ions, matcha, and potassium iodine

Fig.4 Suction filtration with Celite performed
before titration to dilute the color

Fig.5 Matcha solution after filtration

Fig.6 Matcha solution after iodine titration- 55 -

III. Data Analysis
Experiment 1: Formalin Treatment
Results from Experiment 1 indicate that 1.0 g of matcha and tannic acid formed small lumps, withalmost the entire amount polymerizing with formalin. However, in the case of 10.0 g of matcha and 5.0 gof tannic acid, despite their larger mass allowing for a longer reaction time, not all the mixture could bepolymerized. This led to the hypothesis that the unreacted matcha and tannic acid were washed away,
resulting in a significant decrease in mass compared to the samples with 1.0 g of matcha and tannic acid.

Fig.7 Masses of matcha and tannic acid before and after formalin treatment

Experiment 2: Removal of Metal Ions in Water
In Experiment 2, it was observed that matcha post-formalin treatment was more resistant tobreaking and had larger particle sizes. This resulted in a reduced surface area compared to thematcha before formalin treatment, leading to a lower efficiency.

- 56 -

Fig.8 Amount of copper (II) ions in the aqueous solution after attempting removal of
metal ions by matcha and tannic acid, calculated by iodine titration. Fromleft to right: copper (II) ion only, matcha, matcha after formalin treatment,tannic acid, and tannic acid after formalin treatment.

IV. Discussion
Experiment 1: Formalin Treatment
The color of the obtained formalin-treated matcha was dark brown, and the color offormalin-treated tannic acid was light brown. As shown in Figure 7, all of the masses of matcha
and tannic acid were smaller after formalin treatment. Due to their larger mass, 10.0 g of matcha
and 5.0 g of tannic acid could react for a longer time than 1.0 g of matcha and tannic acid, but theentire mixture could not be polymerized. Therefore, we considered that unreacted matcha andtannic acid were washed away, and the mass decreased significantly compared to 1.0g of matcha
and tannic acid.
Experiment 2: Removal of Metal Ions in Water
It was found that the removal efficiency of copper (II) ions when matcha was used as a collection
and removal agent was 82%, which was the highest rate of removal of copper (II) ions. On the other hand,
the removal efficiency when formalin-treated matcha was used was 59%. The removal rate decreased- 57 -

significantly when formalin treatment was used to make matcha into a polymer. The original hypothesis
was that if matcha was made into a polymer, the removal efficiency would be significantly lower. The
results contradicted the hypothesis that this would enable the adsorption of even more heavy metal ions.
The reason for this is that matcha before formalin treatment had a smooth texture, whereas matcha after
formalin treatment had a rough texture because it was not sufficiently ground. From this, it was
hypothesized that the surface area of matcha before formalin treatment was larger than that of matcha
after treatment, which may make it easier for hydroxyl groups to coordinate with copper (II) ions.
In an experiment using tannic acid, which was used for comparison with polyphenols, tannic acidwas 33%, and formalin-treated tannic acid was 59%. Tannic acid was treated with formalin and made intoa polymer, which increased the removal rate. Matcha and tannic acid had opposite results before and after
formalin treatment. Comparing matcha and tannic acid, matcha has a higher removal rate.

V. Conclusion
The results from the experiments proved that matcha and tannic acid before formalintreatment can sufficiently remove copper ions from water, and that tannic acid after formalintreatment has a slightly higher removal rate. However, the results were not as high as expected.
In addition, the matcha was hard after formalin treatment and could not be crushed completely,
which was thought to have impacted its effectiveness.
The experiment demonstrated that matcha and tannic acid can potentially remove metal
ions from water, though the treatment process influences their effectiveness. During the formalintreatment, temperature and time found to be important factors in allowing all the tannic acid toreact with the matcha.
VI. Future Research
The stirring time should be increased to avoid reducing the amount of matcha and tannic acidduring formalin treatment. The difference in surface area of matcha before and after formalin treatment
should also be compared by measuring and calculating the microscopic powder distribution.

- 58 -

It was difficult to maintain an effective surface area when using powders. Tea leaves should be
used instead of powdered matcha to reduce the difference in surface area.
Also, at the JSSF poster session, we received many questions about how to apply the results of thisexperiment to the real world. Therefore, the experiment will continue to think about how our experiments
can affect society.

VII. Acknowledgements
We would like to express our deep gratitude to our research supervisors, Satoshi Yanagiya,
Dr. Mie Ichikawa, and Dr. Noriyuki Matsuura, for their patient guidance, enthusiastic
encouragement, and helpful critiques of this research work. We would also like to thank Mr.
Yuta Matsukawa of the College of Life Sciences in the Department of Applied Chemistry at
Ritsumeikan University for their advice and assistance in the data analysis and for helping us
gather information for this research. In addition, we would also like to extend our thanks to all
the teachers who helped us throughout the writing process. Finally, we would like to thank ourfamilies and classmates for their support and encouragement these past two years.
VIII. References
Goto, T., Horie, H., Ozeki, Y., Masuda, H., & Warashina, J. (1994). Chemical Composition of JapaneseGreen Teas on Market. Chagyo Kenkyu Hokoku (Tea Research Journal), 1994(80), 23–28.
https://doi.org/10.5979/cha.1994.80_23
Kimura, M., Yamashita, H., & Komada, J. (1986). Use of green tea as an adsorbent of several metal ionsin water. Bunseki Kagaku, 35(4), 400–405. https://doi.org/10.2116/bunsekikagaku.35.4_400
Kimura, M. (1992). Chemistry & Education, 40(5), 296-300. https://doi.org/10.20665/kakyoshi.40.5_296
Matsuoka, M. (2014). Iodometric Titration: Determination of Copper (II) Ions (Experiment Manual for
Beginners, Experiment Square). Chemistry & Education, 62(12), 594-595.
https://doi.org/https://doi.org/10.20665/kakyoshi.62.12_594- 59 -Collecting and Removing Heavy Metal Ions in Water Using Matcha
Ritsumeikan High School
Introduction
Matcha is crushed tea leaves, and it is a traditional Japanese drink. Matcha contains tannins, amino acids, and caffeine. 10.57% of matcha's component are tannic acid. The tannin structure contains abenzene ring, and the hydroxy group directly attached to the benzene ring can coordinate to metal ions. It is known that phenol resin, a synthetic resin, can be obtained by combining phenol with formalin.
Applying this technique, tannins instead of phenols could potentially remove heavy metal ions from water by utilizing their binding with the metal ions. For this reason, we tried to remove metal ions fromwater using matcha and tannic acid.

This research focused on Matcha

Materials
・Matcha・​Formalin
・Sulfuric acid・Tannic acid・Copper ion(II)・Rotor・Ion exchange water・Round bottom flask
・Triangular flask
・Hole pipette

Matcha consists of about 10%
matcha polyphenols. Matcha
polyphenols contain a hydroxy
Hydroxy group
Hydroxylategroup which attaches directly tothe benzene ring. HydroxylatesOOwith a proton removed from theR
HR
hydroxy group can bond to metal
ions. By using this property, we
Proton are removed
tried to collect and remove heavy
Metal ions metal ions from water.

Benzene ring
HO

OH

HO
O
Fig.1 Matcha

O

Fig.3 Matcha Polyphenols

Fig.2 Water BathExperiment 1

Experiment 2

MethodMethod

1. Formalin treatment
Formalin treatment was used for the polymerization of
Matcha and of tannic acid.

2. Removal of metal ions in water
Iodometric titration, a quantitative method for copper(II) ions, was used to determine the amount ofcopper(II) ions.

The Matcha used in this experiment was produced in Kyoto, Japan. 5.0
mL of formalin and 20.0 mL of 0.10 mol/L sulfuric acid were added per
1.0 g of Matcha in a 100 mL eggplant-shaped flask and stirred at 60°C
for 2 hours (Fig.4). After formalin treatment, the matcha was filteredthrough an aspirator to remove the formalin (Fig.5). The Matcha wasthen washed with 100 mL of ion-exchanged water (Fig.6). Then, it wasdried and crushed. The experiment was conducted once for eachamount of 1.0 g and 10 g of Matcha and 1.0 g and 5.0 g of tannic acid.

0.25 g of formalin-treated matcha powder was added to the solution containing copper(II) ions and stirred for 30
minutes to remove the metal ions (Fig.8). 0.60 g of potassium iodide was added. While stirring with a stirrer, sodium
thiosulfate was added using a burette and titrated for one hour. The removal rates of Matcha powder without formalin,tannic acid after formalin treatment, and tannic acid without formalin treatment were also examined undersimilar conditions. ​The same experiment was conducted with tannic acid.

Na₂S₂O₃aq[mol/L]×drop volume/1000[L]= Amount of copper(Ⅱ) ion [mol]Fig.8 Matcha before filtration
Fig.4 Stirred at 60℃

Fig.5 FilteredFig.9 Matcha after filtration

Fig.10 Scheme of experimentFig.6 Washed

Result and Discussion

Fig.8 Stirred

Result and Discussion

1.0 g of Matcha and tannic acid produced a small mass, almost all ofthem could be polymerized with formalin. 10.0 g of Matcha and 5.0 gof tannic acid had larger masses, so which allowed them to react for alonger time than the 1.0 g Matcha and tannic acid, but all of the
mixtures could not be polymerized. Therefore, unreacted Matcha andtannic acid were washed away, and the mass decreased by a lot morethan 1.0 g of Matcha or tannic acid.

Fig.11 Amount of copper(Ⅱ) ionsFig.7 Weight before and after formalin-treatment

Matcha and tannic acid before formalin treatment alsosufficiently adsorbed copper(II) ions.
Comparing tannic acid before formalin treatment andtannic acid after formalin treatment, the latter adsorbed
copper ions better.
Comparing Matcha before formalin treatment and tannic
acid after formalin treatment, Matcha before formalintreatment adsorbed more copper(II) ions.

Fig.12 Matcha + HCHO

Fig.13 Tannic acid + HCHOMatcha after formalin treatment was difficult to crush,
but tannic acid after formalin treatment quickly
crumbled into powder.
Therefore, it is thought that the Matcha after formalintreatment was unbroken and had larger particles, andthe surface area was smaller than that of Matcha
before formalin treatment, resulting in poor removal
efficiency.

Future Plan
●The difference in the surface area of Matcha before and after formalin treatment should be compared by measuring and calculating the microscopic powder distribution.
●Using a powder made it difficult to maintain an effective surface area. In order to reduce the difference in surface area, tea leaves will be used instead of powdered Matcha.

References & Acknowledgements
Ref.1 Goto, T., Horie, H., Ozeki, Y., Masuda, H., & Warashina, J. (1994). Chemical Composition of Japanese Green Teas on Market. Chagyo Kenkyu Hokoku (Tea Research Journal), 1994(80), 23–28.
https://doi.org/10.5979/cha.1994.80_23
Ref.2 Kimura, M., Yamashita, H., & Komada, J. (1986). Use of green tea as an adsorbent of several metal ions in water. BUNSEKI KAGAKU, 35(4), 400–405.
https://doi.org/10.2116/bunsekikagaku.35.4_400
Ref.3 Kimura, M. (1992).Chemistry & education, 40(5), 296-300. https://doi.org/10.20665/kakyoshi.40.5_296
Ref.4 Matsuoka, M. (2014). Iodometric Titration: Determination of Copper(II) Ions (Experiment Manual for Beginners, Experiment Square). Chemistry & education, 62(12), 594-595.
https://doi.org/https://doi.org/10.20665/kakyoshi.62.12_594
Dr. Yuta Matsukawa, College of Life Sciences, Department of Applied chemistry, Ritsumeikan University.

傘の形状の違いと表面に残る雨水の関係について要旨
雨が降った後に傘に残る水滴は屋内の床を濡らしてしまう。現在この問題を防ぐ方法として日本の多くの商業施設ではポリエチレン製の傘袋を採用している。しかし昨今のプラスチックゴミを減らして環境負荷を抑制するという社会の要求に対してこの方法は適しているとは言えない。この問
題を根本的に解決するためには、建物内に雨水を持ち込まぬよう、傘の表面についた雨水を建物外でできるだけ取り除きやすくすることが必要だと考えられる。本研究では特に傘の形状に注目してこの問題の解決策を目指した。一般的にコンビニエンスストア等で販売されているビニール傘の表面はポリエステルでできている。そのため、同じ素材であるポリエステル製のラミネートフィルム
で、傘の開く角度の異なる 7 つのサンプルを作製し、雨水を模した霧吹きで水を吹きかける実験を行い、傘の開く角度と傘に残る雨水量の関係を調べた。その結果、傘の開く角度が小さくなるにつれて、単位面積あたりの雨水の量も減少することがわかった。
手順① ケント紙を、コンパスカッターを用いて

1. 背景

半径 6 cm の円状に切り取った。(図１)

雨が降った際に日本人のほとんどは傘を使用する。使い終わった後、濡れた傘をそのまま屋

手順②

中心角を 330°, 315°, 300°, 285°,

内へ持ち込むと、床が濡れてしまう。この問題

270°, 255°, 240°とし、分度器を用いての解決方法としてポリエステル製の傘袋を使う

計測し手順①で作製した円を加工した。

方法がある。しかしながら、使い捨てであるた

手順③

手順②で作成された円を、ラミネータ

めこの方法は環境への負荷が大きい。そこで根ーを用いてラミネートした。その際、切本的な解決方法として、屋内へ持ち込む前に傘り取った円の重なりを瞬間接着剤用の“のの表面に付着した水滴を除去しやすくなるよう、りしろ”として残した。
手順④

傘を改良することが考えられる。

瞬間接着剤で固定した。

既に行われている方法として撥水加工を施すことが挙げられるが、これは一時的なもので時

手順③で作製したものを円錐状に丸め、手順⑤

２種類のスマートフォンのアプリケー

間が経つと効きづらくなることもあり、今回はションを使用し水平な状態で写真を撮影

傘の形状のみに着目し、水滴が残らないようなし、分析した。(図 2)

傘の最適角度を実験によって調べることとした。

手順⑥

手順⑤から得られた値と中心角から計算される値を比較しグラフにまとめた。

2. 方法
2.1. サンプル制作

サンプルに使用した材料は、ケント紙とラミ

本研究では初めにサンプルを製作し、その後

ネートフィルムである。傘の表面が滑らかでな実験を行った。サンプル制作の手順は以下のとければ、表面の小さな凹凸に水が溜まることでおりである。

実験結果に生じる誤差が大きくなると考え、滑- 61 -

手順⑥

らかと平らという２つの特徴を持っているケン

全体を秤量し、水が受け皿に落ちない

ト紙が適していると判断した。またラミネート

ようにセームタオルを用いてサンプル

フィルムはビニール傘に使われている素材と同を取り除いた。

じ素材が使用されているので、こちらも実験に

手順⑦

受け皿に付着した水を秤量し、算出した。

適していると判断した。

この実験では、霧吹きから出る水を雨に見立て、使用した水は室温に戻した。また、サンプルが受け皿に直接置かれた場合、サンプル下部に水が付着し、実験結果に影響が出ることを考慮し、手順③の木片を使用した。また、風の影
響は考慮していない。

図1

切り取られたケント紙

図 2 撮影したサンプル

2.2. サンプルへの雨滴の散布実験
サンプル制作後、実験を行った。実験の手順

図3

は以下の通りである。
手順① 実験前に温度と湿度を測定した。
手順②

電子天秤の上に受け皿を置き、その上に木片を置いた。

3. 結果と考察
3.1. サンプルの開閉角度の妥当性の検討
２種類のスマートフォン用アプリケーション

手順③ サンプルを木片の上に置いた。
手順④

図 3 に示すように、金網を使って傘の上端から 29.5cm の高さに霧吹き器を設を使用しサンプルの水平状態を保った上で写真を撮影したものを図４に示す。

置した。
手順⑤

実験の様子

サンプルに霧吹きで水（約 10g）を噴霧した。

- 62 -

・表面積あたりの水量
𝑀𝑀 ×

360
𝜃𝜃

×

1

𝜋𝜋𝑟𝑟 2・水平投影面積当たりの水量
𝑀𝑀 × (

360 2
1
) × 2
𝜃𝜃
𝜋𝜋𝑟𝑟

𝑀𝑀＝水量の平均値（g）
図4

𝑟𝑟＝半径(cm)𝜃𝜃＝中心角(°)

中心角と開閉角の関係とその誤差

傘の表面と傘の中心を通る垂直な直線の間の角度を「開閉角」とすると、その値は上図中の表の二行目に示される。また計算方法は、以下の式を用いた。
開閉角 ＝ 弧 sin(中心角/360)

図 5 表面積あたりの水量のグラフ

使用した中心角の範囲では、中心角から計算される開角から計算される開角は sin の逆関数であり、この関数は直線で近似できる。上記の表から、理論値と実数値との誤差は 1°以内に収まっているため、この模型は実験に用いるに適しているとみなした。

図 6 水平投影面積あたりの水量のグラフ

3.2. 実験
今回は 2 日間で計 6 回の実験を行った。2 日間

単位面積当たりの水量は、開閉角が変化するの気温と湿度は、1 日目が 25℃：40％、2 日目がにつれて、ほぼ単純に減少する。開傘角度が大26℃：37％と大きな差はなかった。

きいものほど、近似直線と実測値の平均値との結果を各角度の箱ひげ図にまとめた。緑色は 1
日目の平均、青色は 2 日目の平均を表す。オレン

幅が大きいのは、開閉角の違いによる落ちる水
滴の大きさによるものだと考えられる。

ジは全体の平均を表し、オレンジの点線はそのこれには傘の縁に水が滞留していることも大近似線を表している。図５のグラフは単位表面きな要因であった。また、霧吹きから噴射され積あたりの水量に関するものである。また、図た水が傘の表面に落ちた際、表面に留まってい６のグラフは水平投影面積あたりの水量を示した水が他の水滴に吸収されて流れ落ちる。このており、これらの面積は以下の計算式より算出

現象は開閉角が小さいものほど多く見られ、開される。

閉角が小さいものは測定のたびに値が変化する
ことが多かった。

- 63 -

4. 展望わらないと考えられるが、大粒の雨であれば地本研究から、市販の傘に付属している「露先」

上の温度よりも低くなることも考えられる。次という部品は、布を伸ばすだけでなく、水を落

は水滴の大きさの調節や水温を変更し実験を行としやすくするという役割も果たしていると考う。これらの実験が終了し、理想的な形状を決えられた。そう考えた理由は、実験中(図７を参定したのち、さまざまな素材の中で、どの素材

照)のように、サンプルの縁により多くの水が溜が一番適しているかを考えることができる。例

まっていたことが関係している。このような現

えば、晴雨兼用傘は綿や麻でできており、ビニ

象は、本物の傘を使っているときには起こりにール傘とその他の日傘の違いを考えることも可

くい。また、小さい角度ほど縁の面積が少ない能である。

ということからも縁に適した角度と頂点に適した角度が異なっており、それらを組み合わせる

５. 引用文献

ことでより良い結果が得られると考えられた。

・Angle Master 360.(2019).Angle
master(Version 5.02)[スマートフォン]app
store.
・DIY 水平器-カメラで確認しながら水平を確認できる(Version 1.04)[スマートフォン]app
store.

図 7．(左)鉛直上方より撮影 (右)水平方向より撮影

今回の実験では傘のサンプルは骨の部分が直線であったが、一般に販売、流通している多くの傘は直線ではない。そこで今後の研究では、2つ以上の角度を組み合わせた傘の形状や、滑らかな曲線のサンプルを作れば、今回の結果と比較することができるだろう。2 つ以上の角度を組み合わせる場合、上部には大きな角度を用い、端部には小さな角度を用いる。また表面張力の
大きさは水の温度にも依存する。そこで、次は雨の温度に近い 0℃付近の水を用いて実験を行う。
今回用いたような霧吹きによってつくられる
サイズの雨滴の温度は、地上の気温とさほど変- 64 -

The Relationship between the Shapes of Umbrellas
and the Number of Raindrops that Remains on the Surface

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
After it rains, many raindrops remain on the surface of the umbrella. Then, the umbrella is closed,
and raindrops fall to the floor. There are ways to prevent this problem, but many commercial
facilities in Japan have adopted polyethylene umbrella bags. However, this method harms theenvironment because it produces a lot of plastic waste. At the root of this problem is the water thatis brought into the building, and the solution to this problem is to remove as much rainwater as
possible from the surface of the umbrella outside of the building. This research does not focus on
temporary solutions such as waterproof umbrellas, but the shape of umbrellas which would be apermanent solution. This research focuses on the opening angle of an umbrella, which allows waterto drop more easily to the ground. Typically, the surface of the umbrella is made of polyester. This
research made seven samples of laminated film made of polyester at different angles. As a result,as the opening angle of the umbrella decreases, the amount of rainwater per unit area also decreases.
Samples were made at the central angle. But for the range of central angles used in this study, theopening angle calculated from the central angle is an inverse function of sin, and a straight line
can approximate this function. In future research, the number of experiments will increase, and thematerial of samples will vary.
Keywords: umbrella, shape, opening angle, surface, raindrops, remain- 65 -

I. Introduction
After it rains, many raindrops remain on the surface of the umbrella. Then, when theumbrella is closed, the raindrops fall to the floor. One way to prevent this problem is to use
plastic umbrella bags. However, this produces a lot of waste, leads to environmental problems,
and wet plastic bags require more energy to deal with. Thus, it can be suggested that changing
the shape of the umbrella will improve efficiency in removing surface raindrops more easily. In
this research, seven sample umbrellas with different opening angles were made. Then the water
fired from the misting sprayer was used as rain to record the state of removing water.
II. Materials and Method
Making Samples
Kent paper, a compass, scissors, a protractor, super glue, a laminator, laminating film,
compass cutter, and plastic clay were used to make samples. The materials used for the samples
were Kent paper and laminated film. It was assumed that if the paper were not smooth and flat,water would be held in the small holes, which could lead to errors in the experiment results.
However, Kent paper is smooth and flat, which was suitable for this study. Also, laminate film isthe same material used for plastic umbrellas, so it was also determined to be suitable. Sevenkinds of different shapes of samples were made and experimented upon.
First, Kent paper was cut into circles with a radius of 6 cm using a compass cutter. These
circles were then cut as shown in Figure 1. The central angles were 330°, 315°, 300°, 285°, 270°,
255°, and 240°. After this, they were laminated using a laminator and circles were cut out. The
cut-out circle overlap was left as an instant adhesive allowance. Next, each was rolled up into a
conical shape and fixed with super glue. Finally, two apps were used to measure the angle of a

- 66 -

photo taken horizontally to compare with the theoretical value. One app checks the horizontalityof the iPhone. Another app measures the angle between two lines.

Fig.1 Kent paper with center corner cut out

Fig.2 Sample viewed from the side

Experiment
For this experiment, materials such as a saucer, a wood piece (50 mm square), a plastic
bottle, a misting sprayer, military gloves, an electronic balance, tap water, a wire net, a chamois
towel, and a thermometer and hygrometer were utilized.
Initially, the ambient temperature and humidity were measured to set a baseline for theexperiment. Following this, a saucer was placed on the electronic balance, and a piece of wood
was positioned atop it.
The next step involved placing the model on the wood piece. This assembly was weighed,and the data were recorded in a table. A wire net was positioned to simulate rainfall to hold amisting sprayer 29.5 cm above the umbrella's top, as illustrated in Figure 2.
Subsequently, the samples were sprayed with approximately 10 g of water using themisting sprayer. After spraying, each sample, now bearing water, was weighed again. A chamois
towel was used to remove the sample carefully to prevent water from dripping onto the saucer.
The final step of the procedure was to weigh the water collected on the saucer. Thismeasurement was used to calculate the umbrella's effectiveness in shedding water.

- 67 -

Fig.3 Experiment setup

Fig.4 View from above

Fig.5 View from the side

In this experiment, the water emitted from the misting sprayer was simulated as rain, andthe water used was returned to room temperature. Also, a piece of wood was used to ensure that
there would not be errors in the values. If this were not used, the sample would be placed directlyon the saucer. In this case, the water would be on the bottom of the sample, and it would be
impossible to remove the sample. So, a piece of wood prevents this from happening. In Addition,
since sufficient water was applied to the umbrella, the effect of wind is not considered.
III. Data Analysis
Making Samples
The angle between the surface of the sample and the vertical axis is called the opening
angle. These calculations of angles are as follows:
・The opening angle = arcsin(θ/360)
・The Amount of Water per unit Surface Area
= M*360/θ/r ²*PI・The Amount of Water per unit of Horizontal Projection
Area = M/(360/0) ²*pI

- 68 -

The theoretical values are in the second row, and the measured values are in the third rowof Figure 6. The difference between them is less than 1 degree in each column. So, these wereconsidered suitable to use in the experiment.

Fig.6 Relationship between center angle and opening angle and their errors

Experiment
A total of six experiments were conducted over two days. The temperature and humidity
on the two days did not differ significantly: 25°C:40% on Day 1 and 26°C:37% on Day 2.
Therefore, the results were combined into a box-and-whisker diagram for each angle. The green
color represents the average of Day 1, and the blue color represents the average of Day 2. Orange
represents the total mean, and the orange dotted line represents its approximate line. Figure 7 isrelated to the amount of water per unit surface area. Figure 8 shows the amount of water per
horizontal projection area.

- 69 -

Fig.7 Amount of water per unit of surface area for each opening angle.

Fig.8 Amount of water per unit of the horizontal projection area

IV. Discussion
As illustrated in Fig. 7, an analysis of the data reveals a notable trend: the amount of waterretained per unit area on the umbrella samples tends to decrease as the opening angles change.

- 70 -

This decrease in water retention is more pronounced in umbrellas with larger opening angles. A
key factor contributing to this trend is the variation in the speed at which water flows off theumbrella at different angles. Water accumulation at the umbrella's rim also played a significant
role in this phenomenon.
Moreover, it was observed that when water from the misting sprayer landed on theumbrella's surface, the existing water droplets absorbed the new ones and flowed downwards.
This process was more commonly seen in samples with smaller opening angles. As a result, themeasured values for umbrellas with smaller opening angles showed more variability with eachmeasurement.
V. Conclusion
From this research, it was thought that the "dew-tip" component on commercial umbrellas
not only stretches the cloth but also plays a role in facilitating water removal. This thought isbecause of the phenomenon of water remaining on the edges of the cloth. This phenomenon isunlikely to occur when using a real umbrella. In addition, the angles suitable for the edges andthose suitable for the vertices were different, and it was thought that combining them would yield
better results.
VI. Future Research
In this experiment, the sample of the umbrella was straight. However, most umbrella
canopies are not straight. So, for future research, if shapes of umbrellas combining two or moreangles or a smooth curved sample are made, it would be possible to compare the results with thepresent results. When combining two or more angles, a large angle would be used for the top anda smaller angle for the edges. In addition, the magnitude of surface tension also depends on thetemperature of the water. Therefore, the next experiment would use water near 0°C, close to the- 71 -

rain temperature. After finding the optimal shape, experiments. Which material is best suited forvarious materials can be considered. For example, plastic umbrellas are made of cotton andhemp, and it is possible to consider the difference between a plastic umbrella and a parasol.
VII. Acknowledgements
We would like to thank our advisors, Dr. Mie Ichikawa and Mr. Ryojiro Tsujimoto, fortheir helpful advice and guidance throughout our research project.
VIII. References
Angle Meter 360. (2019). Angle Meter (Version 5.02) [Mobile App]. Apple Store.
https://apps.apple.com/jp/app/angle-meter-360/id1393860479
DIY 水平器-カメラで確認しながら水平を確認できる [DIY leveler-Leveling can be checked with thecamera]. (2023). (Version 1.04) [Mobile App]. Apple Store. https://apps.apple.com/jp/app/DIY 水
平器-カメラで確認しながら水平を確認できる/id6449055203- 72 -

The Relationship between the Shapes of Umbrellas andthe Amount of Raindrops that Remains on the Surface
Ritsumeikan High School

Abstract
After it rains, many raindrops often remain on the surface of the umbrella. Moreover, when the umbrella is closed, raindrops fall onto the floor. Currently, there areways to prevent this problem, but many commercial facilities in Japan have adopted the use of polyethylene umbrella bags. However, this method is harmful to theenvironment because it produces a lot of plastic waste. At the root of this problem is the water that is brought into the building, and the solution to this problem isto remove as much rainwater as possible from the surface of the umbrella outside of the building. This research does not focus on temporary solutions such as
waterproof umbrellas, but the shape of umbrella which would provide a permanent solution. This research focuses on the opening angle of an umbrella which allows
water to drop more easily to the ground. Typically, the surface of the umbrella is made of polyester. This research made seven samples at different angles made oflaminated film, made of polyester. As a result, as the opening angle of the umbrella decreases, the amount of rainwater per unit area also decreases. Samples weremade at the central angle. But for the range of central angles used in this study, the opening angle calculated from the central angle is an inverse sin function,and this function can be approximated by a straight line. For future research, the number of experiments will increase, and the material of samples will vary.

Introduction

Results

After it rains, many raindrops often remain on the surface of the umbrella. Whenthe umbrella is closed, these raindrops fall to the floor. One way to prevent thisproblem is by using plastic umbrella bags. However, this produces a lot of waste
and leads to environmental problems. Thus, it can be suggested that changing
the shape of the umbrella could improve its efficiency to remove surface
raindrops more easily. In this research, seven sample umbrellas with different
opening angles were made. Then, a mist was used to imitate rain and theremoval of water was recorded as shown in Fig. 6.

The opening angle= arcsine(θ/360)
The amount of water per
unit surface area
= M*360/θ/r²*PI
The amount of water per unithorizontal projection area
= M/(360/θ) ²*PI

Materials and Methods

θ: Central angle
M: Average of Amount of Waterr: radius

Sample making---------------------------------------------------------------------------(Materials)
Kent paper, Compass, Scissors, Protractor, Super glue, Laminator,
Laminating film, Compass cutter, Plastic clay
(Methods)
1) Kent paper was cut into a radius of 6 cm circles by using a compass cutter.
2) (1) were cut as shown in (Fig.1).The central angles were 330°, 315°,
300°, 285°, 270°, 255°, and 240°.
3) (2) was laminated by using a laminator and circles were cut out. During thistime an overlap was left in the cut-out circles as an allowance for instantadhesive.
4) (3) was rolled up into a conical shape and fixed with super glue.
5) Two apps were used to measure the angle of a photo taken in a horizontal
state to compare with the theoretical value.

Fig.6 Relationship between center angle and opening angles and their errors.

The angle between the surface of sample and vertical axis is called the opening
angle. The theoretical values are in the second row and the measured values arein the third row of Fig. 6. The difference between them is less than 1 degree ineach column.

Average of Day1
Average of Day2
Total averageFig.7 Graphs related to the amount of water per
Fig.8 Graphs related to the amount of water per
unit of surface area.
unit of horizontal projection area.

Fig.1 Kent paper with center corner cut out.

Fig.2 Sample

Experiment--------------------------------------------------------------------------------(Materials)
Saucer, Wood (50 mm square), Plastic bottle, Misting sprayer, Military gloves,
Electronic balance, Tap water, Wire net, Chamois towel,
Thermometer and Hygrometer(Methods)
1) The temperature and humidity were measured before the experiment.
2) A saucer was placed on the electronic balance and a piece of wood wasplaced on top of it.
3) The model was placed on a piece of wood, which was weighed and data wasput in a table.
4) A wire net was used to place a misting sprayer 29.5 cm above the top of theumbrella as shown in (Fig.2).
5) Samples were sprayed with water (about 10 g) by using a misting sprayer.
6) (5) was weighed and the sample was removed by using a chamois towel toprevent water from falling onto the saucer.
7) The water on the saucer was weighed and calculated.

This time, a total of six experiments were conducted over two days. The
temperature and humidity on the two days did not differ significantly: 25°C:40% on
the first day and 26°C:37% on the second day. Therefore, the results werecombined into a box-and-whisker diagram for each angle. The green color
represents the average of Day 1, and the blue color represents the average of Day
2. Orange represents the total mean, and the orange dotted line represents its
approximate line. And the left graph is related to the amount of water per unit
surface area. And the right graph shows the amount of water per horizontal
projection area.

Discussion
The amount of water per unit area decreases gradually as the opening angles
change as shown in (Fig.7). The reason for the larger range between theapproximate straight line and the average of the measured values for those withlarger opening angles was the difference in the speed at which water flows at
different angles. Also, the fact that the water was retained at the rim of theumbrella was a major factor. In addition, when the water that was sprayed from themisting sprayer fell on the surface of the umbrella, the water that stayed on thesurface was absorbed by other drops and flowed down. This appeared more
frequently for those with smaller opening angles, so the values for those withsmaller opening angles often changed with every measurement.

Conclusions / Future Plan

Fig.3 ExperimentFig.4 View from above

Fig.5 View from side

From this research, it was thought that the “dew-tip” component on commercial
umbrellas not only stretches the cloth, but also plays a role in facilitating water
removal. The reason for this thought is because of the phenomenon of waterremaining on the edges of the cloth. This phenomenon is unlikely to occur whenusing a real umbrella. For future research, real plastic umbrellas should be used toconsider the role of dew-tips and use the results to create a model for future
experiments. In this experiment, the sample of the umbrella was straight. However,most umbrella canopies is not straight. So, if a shape combining two or moreangles or a smooth curved sample is produced, it would be possible to compare theresults with the present results. After finding the optimal shape, experiments should
be conducted with a cotton/hemp blend fiber as used in sunshade umbrellas.

References
Angle Meter 360. (2019).Angle Meter (Version 5.02) [Mobile app]. Apple Store.https://apps.apple.com/jp/app/angle-meter-360/id1393860479
DIY水平器-カメラで確認しながら水平を確認できる [DIY leveler-Leveling can be checked with the camera] (2023). (Version 1.04) [Mobile app].Apple Store.

和音に最適な周波数の比

要旨

この研究の目的は、和音の響きを良くするために最適な周波数の比を求めることである。楽器の調律法として一般的な平均律は、最良の響きを持つ和音を奏でることはできない。より良い和音を奏でるためには、音程を調整する必要がある。和音の美しさは、周波数の比の最小公倍数と密接な関係があると考えられる。この考えを元に、重要な和音に最適な周波数の比を求めた。メジャーコードは 4:5:6、マイナーコードは 10:12:15、オーギュメントコードは 16:20:25、ディミニッシュコー
ドは 5:6:7、サスフォーコードは 6:8:9 である。これらの比を活用することで、作曲家や音楽家が綺麗な和音で曲を演奏し、新しい音楽を創造できるようになるだろう。
1. はじめに

表 1 和音の心地良さと倍音の関係

1－1. 背景

基音

2 倍音

3 倍音

4 倍音

5 倍音

6 倍音

私たちが普段から耳にするドレミファソラシ

ド

4

8

12

16

20

24

の音には、それぞれに決まった周波数が割り当て

ミ

5

10

15

20

25

30

られている。このように音の高さの関係を一定の

ソ

6

12

18

24

30

36

方法によって整理したものを音律という。現在広く使われている音律は平均律といい、ピアノなど

1－3. 平均律とはあらゆる楽器の調律に用いられる。しかし複数音

平均律とは現在一般的に使われている音律で、を同時に鳴らした時の響きがイマイチだという

1 オクターブを 12 等分したものだ。音の高さの間欠点がある。そこで音の高さを微調整することで隔が均等であるため、キーを変えても演奏が可能

響きを改善できると考えた。

だという大きな利点がある。そのためピアノなど
あらゆる楽器は平均律で調律されている。しかし

1－2. 和音とは平均律の和音は、周波数の比が簡単な整数比で表和音とは周波数の異なる二つ以上の音を同時に鳴らしたときの合成音のことをいう。人が心地良いと感じる和音は、周波数の比が簡単な整数比

すことができない。そのため倍音同士でうなりが生じて、和音の響きが綺麗にならないという欠点がある。

で表されると言われており、これには倍音の一致やズレが関係している。ピアノなどの楽器で音を1－4. 純正律とは鳴らすと、基本となる音（基音）だけでなく倍音純正律とは和音の響きの綺麗さを重視した音も同時に鳴る。2 つの音の周波数がわずかに異な律だ。
ドミソの和音は周波数の比が 4:5:6 となる。

る時、うなりが生じるため和音が濁って聞こえる。

簡単な整数比で表すことができるため、和音の響

うなりは基音だけでなく倍音同士でも生じる。例

きが心地よい。しかし和音の響きが綺麗にならな

えばドミソの和音は周波数の比が 4:5:6（純正律のい和音もある。レファラの和音は周波数の比が場合）となる。それぞれの倍音の周波数が27:32:40 となる。簡単な整数比とは言えないため、（12,20,24,30…で）一致するためうなりが生じず、和音の響きはあまり良くない。

心地良い響きとなる。

- 74 -

1－5. 最適な和音

6

シックス

ド

ミ

ソ

ラ

和音の綺麗さをより正確に調べることは可能

7

セブンス

ド

ミ

ソ

シ♭

だろうか。周波数の比の最小公倍数が小さい和音

M7

メジャー・セブンス

ド

ミ

ソ

シ

は合成音の周期が短いため、より心地良く聞こえ

マイナー・セブm7ると考えた。純正律では、ドミソの和音の周波数の比は 4:5:6 なので最小公倍数は 60、レファラの和音の周波数の比は 27:32:40 なので最小公倍数は44320 となる。したがって、最小公倍数の小さいド

和

ミソの和音の方がレファラの和音よりも綺麗だ

音

ンス

mM7
dim7

と考えられる。和音の綺麗さは最小公倍数の小ささで決まると仮定して研究を進めることにした。

7(♭5)

2. 実験方法と結果

m7(♭5)

2－1. 使用したもの

7sus4

数字を大量に扱うために Google Apps Script とマイナー・メジャー・セブンス
ディミニッシュ・セブンス
セブンス

ド
ド
ド
ド

（フラッテッド・フィフス）
マイナー・セブンス

ド（フラッテッド・フィフス）
セブンス・サス
フォー

ド

ミ
♭
ミ

ソ

シ
♭

ソ

シ

ミ

ソ

シ

♭

♭

♭♭

ソ

シ

♭

♭

ミ

ソ

シ

♭

♭

♭

♭

ミ

フ
ァ

ソ

シ
♭

Google スプレッドシートを使用した。また Scale
Workshop という入力した音程を手軽に鳴らせる

2－3. 実験 1

Web ページを使用し、実際に和音を聴き比べなが2－3－1. 比のデータを収集する

ら実験を行った。

1 オクターブに収まる 3 和音の周波数の比を求めて表に書き込んだ。1 オクターブに収まる 3 和

2－2. 実験 1 の和音

音を、周波数の比が小さい順に求めるプログラム

実験 1 の目的はよく使われる和音の最適な周波を作成し実行した。3:4:5、4:5:6、4:5:7 と続いた。

数の比を最小公倍数から求めることだ。よく使わまた周波数の比を構成する 3 つの数値の最小公倍れる和音を以下の表 2 にまとめた。3 つの音で構数を求めた。

成される和音（3 和音）の実験から始めた。ただし扱う和音は 1 オクターブの範囲に収まるものとする。1 オクターブとはある音とその 2 倍の周波数を持つ音との間隔のことだ。つまり 1 オクターブに収まる和音は、周波数の比を構成する最大値が最小値の 2 倍未満である場合のみ成り立つ。

表 2 コード一覧

コ ー

読み方

ドの場合）

M

メジャー

ド

ミ

ソ

3

m

マイナー

ド

ミ♭

ソ

和

aug

オーギュメント

ド

ミ

ソ#

音

dim

ディミニッシュ

ド

ミ♭

ソ♭

sus4

サスフォー

ド

ファ

ソ

周波数の比（音 1：音 2：音 3）- 75 -

最小公倍数

3

4

5

60

4

5

6

60

4

5

7

140

4

6

7

84

5

6

7

210

5

6

8

120

…

ド名

構成音（根音が表 3 周波数の比と最小公倍数

2－3－2. 最適な比に並び替える

表 5 平均律の音程（ドを 1 とする場合）

3 つの数値の最大公約数が書かれた列を作成し

音名

周波数の比率その音とみなす範囲た。最大公約数が 2 以上になる列を表示しないフ

ド

1

1

〜

20.5/12

ィルタをかけることで、6:8:10 のように約分可能

ド#

21/12

20.5/12〜21.5/12な周波数の比を取り除いた。また必要な和音は最

レ

22/12

21.5/12〜22.5/12小公倍数の小さいものだけなので、最小公倍数の

レ#

23/12

22.5/12〜23.5/12

小さい順に並び替えた。

ミ

24/12

23.5/12〜24.5/12ファ25/12

24.5/12〜25.5/12

ファ#

26/12

25.5/12〜26.5/12

表 4 最適な周波数の比に並び替え

周波数の比

最小

最大

ソ

27/12

26.5/12〜27.5/12（音 1：音 2：音 3）

公倍数

公約数

ソ#

28/12

27.5/12〜28.5/12

3

4

5

60

1

ラ

29/12

28.5/12〜29.5/12

4

5

6

60

1

ラ#

210/12

29.5/12〜210.5/12

10

12

15

60

1

シ

211/12210.5/12〜

211.5/12

12

15

20

60

1

ド

2

211.5/12

〜

2

6

8

9

72

1

8

9

12

72

1

4

6

7

84

1

…
2－3－3. 比から構成音を求める
表 4 の比で奏でられる和音はどんな音で構成されているのか知る必要があった。まずそのために
3 音は平均律のどの音に最も近いかを調べる方法を考えた。平均律ではどの音の周波数に 21/12 をかけても半音上の音になるという特徴がある。表 5は平均律の音の周波数の比率とその音とみなす
範囲を表している。図 1 はその音とみなす範囲を表している。
図 1 その音とみなす範囲
例えば 4:5:6 の周波数の比を持つ和音では、比の最小値を 1 とした時 1.00:1.25:1.50 になる。1.00
はド、1.25 はミとみなし、1.50 はソとみなせるか
ら構成音はドミソであることがわかる。表 6 は表4 で求めた周波数の比が何の音で構成されている
和音かをまとめたものだ。

- 76 -

表 6 周波数の比に対応する音

最小公倍数

ド

60

3

60

4

60

10

60

12

72

6

72

8

84

4

ド#

レ#

レ

レ♭

ミ

ミ♭

ファ

ファ#
ソ♭

ソ

ソ#

ラ#

ラ

ラ♭

4

シ♭

シ

5

5

6

12

15
15

20
8

9

9

12
6

7

…

2－3－4. 最適な周波数の比を求める
2－3－5. 4 和音に最適な周波数の比を求める

表 2 と表 6 の構成音が一致する和音を調べるこ

3 和音の時と同じ手順で行った。4 和音を構成とで 3 和音に最適な周波数の比を求め、表 7 にまする 4 つの数値を書き出し、最小公倍数の小さいとめた。

順に並べ替え、最大公約数が 1 だけを表示した。
また、それら 4 つの数値からなる和音が何の音で

表 7 3 和音に最適な周波数の比
コード

構成音

名

最適な

最小

周波数の比

公倍数

M

ド

ミ

ソ

4:5:6

60

m

ド

ミ♭

ソ

10:12:15

60

sus4

ド

ファ

ソ

6:8:9

72

dim

ド

ミ♭

ソ♭

5:6:7

210

aug

ド

ミ

ソ#

16:20:25400構成されるか表 8 にまとめた。

表 8 4 和音の周波数の比
周波数の比

ド#
最小公倍数

ド

（音 1：音 2：音 3：音 4）

レ#
レ

レ♭

ファ#
ミ

ファ
ソ♭

ミ♭

8

10

12

15

120

8

9

10

12

15

180

9

10

12

15

18

180

10

12

15

18

20

180

12

10

12

15

16

240

10

12

15

16

20

240

12

15

16

20

24

240

15

12

14

18

21

252

12

14

12

14

16

21

336

12

14

14

16

21

24

336

14

ソ#
ソ

10
10

ラ♭

12

15
15

15
15

15

16
20
24

18

21

16

21
21

- 77 -

20

16
20

16

18

18

12
15

シ

シ♭

12
12

16

ラ#
ラ

24

16

21

24

28

336

16

21

5

6

8

9

360

5

6

8

9

10

360

6

8

9

10

12

360

8

9

10

8

9

10

15

360

8

9

10

24

28

6

8
8

9

9

10

12
15

…

表 2 と表 8 の構成音が一致する和音を調べ、42－5. 実験 1 の課題点の解決策

和音に最適な周波数の比を求めた。

解決策として考えられたのは、ある数値の約数から 3 つの数値や 4 つの数値を取ってくることだ。

表 9 4 和音に最適な周波数の比
コード

構成音

名

1 から 2000（4 和音の最適な周波数の比の最小公

最適な

最小

倍数が 2000 を超えることはないと考えられるか

周波数の比

公倍数

ら十分な数値と言える）まで書き込み、約数の個

M7

ド

ミ

ソ

シ

8:10:12:15

120

数と約数を求めた。これらの約数から 1 オクター

m7

ド

ミ♭

ソ

シ♭

10:12:15:18

180

ブに収まる 3 和音や 4 和音の周波数の比を求める

6

ド

ミ

ソ

ラ

12:15:18:20

180

ことで、最小公倍数が小さい順に比を求めること

7sus4

ド

ファ

ソ

シ♭

16:21:24:28

336ができると考えている。現在検証を進めていると

7

ド

ミ

ソ

シ♭

4:5:6:7420

ころだ。

m7(♭5)

ド

ミ♭

ソ♭

シ♭

5:6:7:9

630

7(♭5)

ド

ミ

ソ♭

シ♭

20:25:28:35

700

dim7

ド

ミ♭

ソ♭

シ♭♭

25:30:35:42

1050

数値

約数の個数

mM7

ド

ミ♭

ソ

シ

10:12:15:19

1140

1

1

1

2

2

1

2

3

2

1

3

実験 1 のやり方には少し問題があった。小さい

4

3

1

2

数値を持つ周波数の比から表に書き込むプログ

5

2

1

5

ラムを実行したことにより、大きい数値を持つ周

6

4

1

2

波数の比を処理するまでに時間がかかったこと

7

2

1

7

だ。3 和音では扱う数値が 3 つだけなので大きな

8

4

1

問題ではない。しかし 4 和音の場合、4:5:6:7 から

9

3

始めて 30:57:58:59 までしか処理できなかったた

10め、大きい数値を持つ最小公倍数が小さい比を見つけることができていない可能性がある。つまり

表 10 約数

2－4. 実験 1 の課題点

約数

3

6

2

4

8

1

3

9

4

1

2

5

10

11

2

1

11

12

6

1

2

3

4

6

12

2000

20

1

2

4

5

10

16

…

実験 1 で求めた「和音に最適な周波数の比」は完
璧ではない可能性がある。

- 78 -

4…

2－6. 実験 2 の目的比率は以下のようになっている。

実験 2 の目的は実験 1 で求めた和音に最適な周
表 11 純正律の音程

波数の比を活用し、音程を調整することだ。純正律を基盤にして考え、心地悪いレファラの和音の

ド

レ

ミ

ファ

ソ

ラ

シ

響きを改善する。

1/1

9/8

5/4

4/3

3/2

5/3

15/8

2－7. 実験 2

これらの音程で作ることができるダイアトニ

2－7－1. C メジャースケールにおけるダイアト

ックコード 7 種類の周波数の比を表 12 にまとめ

ニックコードた。

C メジャースケールとはドの音から始まる長音

表 12 からわかるように、
Dm コード（レファラ）

階のことで、「ドレミファソラシ」の 7 音で構成さと Bdim コード（シレファ）の周波数の比が実験れている。C メジャースケールにおけるダイアト

1 で求めた最適な周波数の比と一致していないこ

ニックコードとは「ドレミファソラシ」の 7 音でとがわかる。Dm コードと Bdim コードを最適な作ることができる基本的な和音のことだ。3 和音

周波数の比にするために音程を調整した。
表 13 はの場合「ドミソ」「レファラ」「ミソシ」「ファラド」

ダイアトニックコードを弾くときにどの音程を

「ソシレ」
「ラドミ」
「シレファ」の 7 種類となる。

使えば最適になるかをまとめたものだ。Dm コー

これらは C、Dm、Em、F、G、Am、Bdim と書く

ド（レファラ）を弾くときはレの音程を 9/8 からことができる。これらは C メジャースケールにお10/9 に少し下げることで、最適な周波数の比であいて最も重要な和音であるため、最適な周波数のる 10:12:15 を実現した。また Bdim コード（シレ比で鳴らせる必要があった。

ファ）を弾くときはファの音程を 4/3 から 21/16 に少し下げることで、最適な周波数の比である 5:6:7

2－7－2. C メジャースケールの音程を考え直すを実現した。

純正律ではドを 1 としたときの音程の周波数の表 12 ダイアトニックコードの周波数の比
コード名

C

Dm

Em

F

G

Am

Bdim

構成音

ドミソ

レファラ

ミソシ

ファラド

ソシレ

ラドミ

シレファ

コードの種類

M

m

m

M

M

m

dim

周波数の比

4:5:6

27:32:40

10:12:15

4:5:6

4:5:6

10:12:15

45:54:64

最適な周波数の比

4:5:6

10:12:15

10:12:15

4:5:6

4:5:6

10:12:15

5:6:7

ラ

シ

表 13 ダイアトニックコードの最適な音程

ド

C

レ

1/1

Dm

10/9

Bdim

ソ

3/2
4/3

5/4
1/1

G
Am

ファ

5/4

Em
F

ミ

5/3
3/2

4/3
9/8

1/1

5/3
3/2

5/4
9/8

15/8
15/8
5/3

21/16

- 79 -

15/8

3. 考察Dm コードや Bdim コードを弾くときに、これらの調整した音程に切り替えることができたらより綺麗に曲を演奏できると考えられる。しかし実際に人間が複数の音程を使い分けるのは難しいだろう。
4. 今後の展望①より多くの和音の最適な音程を求める

4 和音のダイアトニックコードやノンダイアトニ
ックコードであるセカンダリードミナントなどのよく使われる和音に対応するために、音程の調整の仕方を音楽理論から考える必要がある。
②

楽器アプリを作る

状況に応じて最適な音程を使い分けるのは難し
いので、和音を弾くと自動的に最適な音程に調整される楽器を作る。Unity というゲームエンジンで制作し、スマホやパソコンで演奏できるようにする予定だ。
③

曲を聴き比べる

平均律の楽器、純正律の楽器、最適な音程に自動調整される楽器をアプリ上で曲を演奏し、聴き比べる。これにより本当に曲が心地良く聞こえるのかを調べ、実用性があるか確かめる必要がある。
5. 参考文献
Ref.1 「ピタゴラス音律から新しい音律へ」馬場良
始 URL:
http://www.osaka-kyoiku.ac.jp/~ybaba/onritsu2.pdf
アクセス日: 2023/10/31
Ref.2 中村 健太郎（2010）「図解雑学 音のしくみ」
ナツメ社- 80 -

Optimal Frequency Ratio for Chords

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
This research aims to determine the optimal frequency ratios to enhance chord quality. While equal
temperament, a commonly used tuning method for instruments like the piano, has its merits, itcannot produce the best-sounding chords. To address this issue, adjusting the intervals is essential
to obtain better-sounding chords. The beauty of chords is closely linked to the least common
multiple (LCM) of their frequency ratios. Through this research, optimal frequency ratios havebeen identified for various chord types: Major chords: 4:5:6, Minor chords: 10:12:15, Augmented
chords: 16:20:25, Diminished chords: 5:6:7, and Suspended 4th chords: 6:8:9. Utilizing theseratios helps musicians create more beautiful chords. For future research, an instrument will becreated to be used on a computer or mobile phone. This instrument will be able to adjust optimal
intervals automatically.
Keywords: frequency ratio, chord quality, least common multiple, interval- 81 -

I. Introduction
A chord is a composite sound when three or more notes of different pitches are played
simultaneously. It produces harmony, which sounds better when its frequency ratio is expressed
as a simple integer ratio.
Equal temperament, widely used today, is one octave divided into 12 parts where the ratios
between adjacent notes are equal. Since the intervals are equal, it is possible to play in different
keys. However, it does not produce a beautiful chord sound because the frequency ratios of thechords cannot be expressed in integer ratios.
Just intonation is an excellent temperament for making beautiful-sounding chords. In justintonation, the C major chord (C-E-G) sounds beautiful. This is because the frequency ratio is
4:5:6, a simple integer ratio. However, the D minor chord (D-F-A) does not sound good. This isbecause the frequency ratio is 27:32:40, which is not a simple integer ratio. It is considered that
more beautiful chords can be played by adjusting the intervals of the D minor chord.
Chords with smaller LCM frequency ratios could sound more beautiful because of theshorter period of the composite waveforms. In just intonation, the frequency ratio of the C major
chord (C-E-G) is 4:5:6, so its LCM is 60; the frequency ratio of the D minor chord (D-F-A) is
27:32:40, so its LCM is 4320. Therefore, the C major chord with the LCM of 60 is consideredmore beautiful than the D minor chord with the LCM of 4320.
II. Materials and Method
A MacBook Air M1 is used for the experiments.

- 82 -

III. Data Analysis
Step 1: Sort Frequency Ratios
The frequency ratios of the triads in Table 1 were set so that the largest value was less than
twice the smallest value within the same octave. The order of LCM was sorted from the smallest
to the largest. Only ratios with the greatest common divisor (GCD) of 1 were listed. Table 1
indicates the triads that fit in one octave which sound better toward the top.
Table.1 Optimal frequency ratio of triads

Frequency ratio

LCM

GCD

3

4

5

60

1

4

5

6

60

1

10

12

15

60

1

12

15

20

60

1

6

8

9

72

1

8

9

12

72

1

Step 2: Examine Notes from Ratios
The frequency ratio of basic chords was examined to determine which notes were used forthe chord based on the frequency ratio that was obtained in Step 1. For example, the top row ofTable 2 shows that a chord with a frequency ratio of 3:4:5 is composed of the notes C-F-A.

- 83 -

Table.2 Relation between a frequency ratio and notes

C

C#
Db

D

D#
Eb

E

3

F

F#
Gb

G

G#
Ab

4

4

15
15

6

20
8

8

B

6

12

12

A#
Bb

5

5

10

A

9

9

12

Step 3: List Components of Chords
The component notes from basic chords were confirmed. Table 3 lists the notes thatcompose the basic chords: Major (maj), Minor (min), Augmented (aug), Diminished (dim), andSuspended 4th (sus4).
Table.3 List of chord types and their component notes

Chord type

Component notes

maj

C

E

G

min

C

Eb

G

aug

C

E

G#

dim

C

Eb

Gb

sus4

C

F

G

- 84 -

Step 4: Determine Optimal Ratios

The optimal frequency ratio for each chord was determined by considering Step 2 and Step
3. Table 4 lists the optimal frequency ratios for basic chords: Major: 4:5:6, Minor: 10:12:15,
Augmented: 16:20:25, Diminished: 5:6:7, and Suspended 4th: 6:8:9.
Table.4 Optimal frequency ratios for each chord

Chord type

Ratio

LCM

maj

4 : 5 : 660

min

10 : 12 : 15

60

aug

16 : 20 : 25

400

dim

5 : 6 : 7

210

sus4

6 : 8 : 972

IV. Discussion
Mathematically right things are not always right to hear. We might have been already used
to listening to songs that are not right.
V. Conclusion
The least common multiple determined the optimal frequency ratio of basic chords. This
allowed for the adjustment of intervals in the D minor chord and B diminished chord, as they did
not sound optimal in just intonation, ultimately achieving the desired frequency ratio.
VI. Future Research
In future research, the primary goal is to discover an improved method for calculating
frequency ratios. This is crucial because the current method faces challenges when dealing withnumerous ratios and small common multiples. Additionally, the aim is to develop a musicalinstrument capable of automatically adjusting to the ideal interval when playing chords. This- 85 -

innovation is prompted by the difficulty of manually selecting the correct interval based on themusical context, and the goal is to simplify this process through automation.
VII. Acknowledgements
I wish to thank Mr. Koichiro Hiromatsu for his good advice.
VIII. References
Baba, Y. (2013). Pitagorasu onritsu kara atarashii onritsu he [From Pythagorean temperament to
new temperament]. http://www.osaka-kyoiku.ac.jp/~ybaba/onritsu2.pdf
Nakamura, K. (2010). Zukai zatsugaku oto no shikumi [Illustrated Trivia: How Sound Works].
Sakurai, S. Sakaguchi, H. (2011). Ongaku to suugaku no kousa [The intersection of music andmathematics].
Sakaguchi, H. (2016). Kazu to ongaku [Numbers and music].

- 86 -

Optimal Frequency Ratio for Chords

Ritsumeikan High School

Abstract
This research aims to determine the optimal frequency ratios to enhance chord quality. While equal temperament, a commonly used tuning method for instruments like the piano, has its
merits, it cannot produce the best-sounding chords. To address this issue, adjusting the intervals is essential to obtain better-sounding chords. The beauty of chords is closely linked to theleast common multiple (LCM) of their frequency ratios. Through this research, optimal frequency ratios have been identiﬁed for various chord types: Major chords: 4:5:6, Minor chords:
10:12:15, Augmented chords: 16:20:25, Diminished chords: 5:6:7, and Suspended 4th chords: 6:8:9. Utilizing these ratios helps musicians create more beautiful chords. For future research, an
instrument will be created to be used on a computer or mobile phone. This instrument will be able to adjust optimal intervals automatically.

Introduction

Experiment 2

Chord

Aim

A chord is a composite sound when three or more notes of different pitches are played at
the same time. It produces harmony and the harmony is said to sound better when its
frequency ratio is expressed as a simple integer ratio.

To utilize the optimal frequency ratio for basic chords determined in Experiment 1, theintervals were adjusted to improve the sound of chords by using just intonation.
The ratio of the intervals in just intonation is as follows:

Equal Temperament
Equal temperament, which is widely used today, is one octave divided into 12 parts where
the ratios between adjacent notes are equal. Since the intervals are equal, it is possible toplay in different keys. However, it does not produce a beautiful chord sound because thefrequency ratios of the chords cannot be expressed in integer ratios.

Just Intonation
Just intonation is an excellent temperament for making beautiful sounding chords. In justintonation, the C major chord (C-E-G) sounds beautiful. This is because the frequency ratio
is 4:5:6, which is a simple integer ratio. However, D minor chord (D-F-A) does not soundgood. This is because the frequency ratio is 27:32:40, which is not a simple integer ratio. It isconsidered that by adjusting the intervals of the D minor chord, more beautiful chords canbe played.

Beauty of Chords
Chords with smaller LCM of frequency ratios could be considered to sound more beautiful
because of the shorter period of the composite waveforms. In just intonation, the frequency
ratio of the C major chord (C-E-G) is 4:5:6, so its LCM is 60; the frequency ratio of the Dminor chord (D-F-A) is 27:32:40, so its LCM is 4320. Therefore, the C major chord with the
LCM of 60 is considered more beautiful than the D minor chord with the LCM of 4320.

Experiment 1

Table 5 Just intonation intervals

Notes

C

D

E

F

G

A

B

Ratio to C

1/1

9/8

5/4

4/3

3/2

5/3

15/8

Step 1: Diatonic Chords in C Major Scale
The diatonic chords in the C major scale are the following seven chords shown in Table
6 such as C major, D minor, E minor, F major, G minor, A minor, B diminished. Since
these are the most important chords, these chords had to be able to be played at the
optimal frequency ratio.
Table 6 Diatonic chords and frequency ratios in just intonation

Diatonic chord

Component notes

Chord type

Actual ratio

C major

C-E-G

maj

4:5:6

4:5:6

D minor

D-F-A

min

27:32:40

10:12:15

E minor

E-G-B

min

10:12:15

10:12:15

F major

F-A-C

maj

4:5:6

4:5:6

G major

G-B-D

maj

4:5:6

4:5:6

A minor

A-C-E

min

10:12:15

10:12:15

B diminished

B-D-F

dim

45:54:64

5:6:7

Table 6 shows that two chords, D minor and B diminished, are not optimized. Because
the actual frequency ratio does not match the optimal frequency ratio.

Aim
To determine the optimal frequency ratio of basic triads.

・Major chord
・Minor chord
・Augmented chord・Diminished chord・Suspended 4th chord

Materials
Basic triads on the right were used for Experiment 1:

Step 2: Adjust Intervals
Table 7 below lists the notes that compose each diatonic chord and their intervals. For
D minor chord and B diminished chord, the original intervals were adjusted to obtain
the optimal frequency ratio.

Step 1: Sort Frequency Ratios

Table 7 Notes that compose diatonic chords
Table 1 Optimal frequency ratios of triads

1. The frequency ratios of the triads into
Table 1 was set so that the largest value
was less than twice the smallest value
within the same octave.
2. The order of LCM was sorted from thesmallest to the largest.
3. Only ratios with the greatest common
divisor (GCD) of 1 was listed.
Table 1 indicates the triads that ﬁt in one
octave which sound better toward the top.

Frequency ratio

C

LCM

GCD

3

4

5

60

1

4

5

6

60

1

10

12

15

60

1

12

15

20

60

1

6

8

9

72

1

8

9

12

72

1

C major

The frequency ratio of basic chords was
examined to determine which notes wereused for the chord based on the frequency
ratio that was obtained in Step 1.
For example, the top row of Table 2 showsthat a chord with the frequency ratio of
3:4:5 is composed of the notes C-F-A.

F major

C#
Db

D

D#
Eb

E

3

F

F#
Gb

G

G#
Ab

4

4

20
8

5/3
3/2

4/3
9/8

1/1

15/8
5/3

3/2
5/4

9/8

B

15/8
5/3

21/16

15/8

When playing the D minor chord, the D note was adjusted from its original ratio of 9/8 to10/9 to obtain the optimal frequency ratio of 10:12:15; when playing the B diminishedchord, the F note was adjusted from 4/3 to 21/16 to get 5:6:7.

Conclusions

9

9

The optimal frequency ratio of basic chords was determined in terms of the least common
multiple. This allowed me to adjust the intervals of the D minor chord and B diminishedchord, which did not sound very good in just intonation, to the optimal frequency ratio.

12

Step 3: List Components of Chords

Table 3 List of chord types and its component notes

The component notes from basic chords
was conﬁrmed.
Table 3 lists the notes compose the basic
chords: Major (maj), Minor (min),Augmented (aug), Diminished (dim), andSuspended 4th (sus4).

Chord typeThe optimal frequency ratio for each chord
was determined by considering Step 2 andStep 3.
Table 4 lists the optimal frequency ratios forbasic chords: Major: 4:5:6, Minor: 10:12:15,
Augmented: 16:20:25, Diminished: 5:6:7, andSuspended 4th: 6:8:9.

4/3
5/4

1/1

A

Conclusions / Future Plan

15
15

6

B

G
3/2

6

12

12

A#
Bb

A

F

5

5

10

8

Step 4: Determine Optimal Ratios

10/9

G majorA minorE
5/4

E minor

B diminished

C

D

1/1

D minorTable 2 Relation between a frequency ratio and notes

Step 2: Examine Notes from Ratios

Optimal ratio

Component notes

maj

C

E

G

min

C

Eb

G

aug

C

E

G#

dim

C

Eb

Gb

sus4

C

F

G

Table 4 Optimal frequency ratios for each chord

Future Plan
The following two things are planned:
1. To ﬁnd a more accurate method to calculate the frequency ratio because when the least
common multiple of the frequency ratio was small but the number of the ratio was large,
it could not be processed.
2. To create an instrument that automatically adjusts to the optimal interval when a chordis played, since it is difﬁcult to use the optimal interval depending on the situation.

References

Chord type

Ratio

LCM

1. 桜井進、坂口博樹（2011）音楽と数学の交差

maj

4 : 5 : 660

2. 坂口博樹（2016）数と音楽

min

10 : 12 : 1560

3. ピタゴラス音律から新しい音律へ、馬場良始、URL: http://www.osaka-kyoiku.ac.jp/~ybaba/onritsu2.pdf

aug

16 : 20 : 25

400

4. 中村 健太郎（2010）「図解雑学 音のしくみ」ナツメ社

dim

5 : 6 : 7210

5. Realtime Procedural Audio and Synthesized Piano in Unity 3D, Shahriar Shahrabi, URL:sus4

6 : 8 : 972

https://shahriyarshahrabi.medium.com/realtime-procedural-audio-and-synthesized-piano-in-unity-3d-a98496
a6df5e動画解析による生徒の授業参加状態数値化システムの開発

要旨
日本は教員の過重労働が問題となっている国の一つである。本研究の目的は、二つのプロジェク
トにより構成される第 1 プロジェクトでは教室における出欠を瞬時に取得することである。第 2 プ
ロジェクトでは、教室における授業活動の状況を可視化することである。これらの研究の動機は、教員の負担を軽減するためである。この研究では、教室の動画を撮影し、動画処理の差分法を定期要することで必要な情報を抽出した。第 1 プロジェクトでは、出席をとるために、授業開始時に生徒に録画中のカメラに向かい手や頭などを振ってもらい、後に手動で ROI（Region Of Interest）
を設定し人を抽出した。第 2 プロジェクトでは、授業は 3 時間、生徒の作った YouTube を見る授業、
B４、M１、M２それぞれのプレゼンテーションを見る授業の 4 つのフェーズで構成し、これらの授業
での生徒の活発度を動画解析により算出した値を用いて比較した。結果はビデオ撮影に 1 分間、動画の解析に２分間、合計 3 分かけて出席を取ることができた。次に、授業中の活発度と主観的アン
ケートを比較したが、一致しなかった。その理由は、生徒はただ動画を見ていただけの状態や質問を考えたり、プレゼンテーションの準備をしたりする他のアクティビティでは活発度のアンケート
項目の興味関心を反映しなかったからだと考えられる。ただし、授業における活動、参加度合いである活発度を評価することはできた。今後、教員がその数値を見て、次の授業の準備に役立てることができる。次回は立命館高校の授業で実施する予定である
1. 背景
日本は教員の過重労働が問題になっている国のひとつである。2021 年、全国の公立小中学校

は、スマートフォンやタブレット PC などのアプ
リケーションを通じて、手軽に情報を提供することを目指す。

教員を対象とした調査では、小学校教員の68.2％、中学校教員の 63.3％が「過去 2 年間に

2. 方法

教員を辞めたいと思ったことがある」と回答しこの研究では差分法と呼ばれる画像処理技術ている。こうした教員の負担を少しでも減らすを用いた（図 1）。動画は時間を表すものとしてフため、出欠を自動で確認し、授業の活性度を可レームが、画像には画像情報を表すものとしてピ

視化するシステムを構築する。このシステムでクセルがある。この技術はあるフレームにある全は、授業開始時に教師があらかじめ用意したカピクセルのフレームごとの輝度の違いから、動き

メラで教室を撮影し、プログラムが自動的に画を白ピクセルと黒ピクセルで画像に表すことが像を解析する。このシステムを利用することできる（図 2）。もしその輝度の差の値があらかじで、授業開始時の 5 分間の出席時間を短縮する

め決めておいたノイズとしての値より小さい場

ことができ、教員の業務負担を軽減することが合カウントされない。授業の活発度が高いと、白できる。また、授業時間を確保することがでピクセルの割合は高くなり、逆も同様である（図き、効率的な授業が可能となる。このシステム

3）。実験の対象は大学生 25 人であった。実験は立は、立命館中学校・高等学校をはじめ、さまざ命館大学琵琶湖草津キャンパス機械システム系

まな学校施設での活用が期待される。最終的に第 2 演習室で行った。また iPhone13(version iOS- 88 -

16.1.1)（図 4）、 PC(VAIO Windows 9)、プログラ
ミング言語としての Python とともに差分法を用いた。iPhone は教室の前側の壁の天井付近に設置した．なぜなら全生徒の顔をカメラで映すためである。授業を撮影した動画に対して差分法を用いて動画解析し、白と黒のピクセルで構成されるデータとして結果を出力した。差分法によって検出された白色のピクセルは物体が動いているエリアを検出している。

図 4. iPhone の設置方法

Different image processing
𝑰𝒅 (𝒙, 𝒚)= |𝑰𝒏 (𝒙, 𝒚) − 𝑰𝒏−𝟏 (𝒙, 𝒚)|2－1. 第 1 プロジェクト
第 1 プロジェクトでは授業の始めに、動画を撮

𝑥, 𝑦：Position coordinates in image

影しているカメラに対して手を振ったり、頭を振ったりしてもらった。そして、その様子の動画を

I：Luminance in the image (0-255)

教室の正面にあるカメラで 1 分程度撮影した。あ図 1. 差分法

らかじめ ROI を設定しておき（図 5）、その中で白ピクセルの割合が大きいと、出席と判断する。解析方法としては生徒が座席にいることを確認するために ROI を手動で画像上の各座席に設定し、それぞれの ROI の中での輝度の違いを計測した

図 2. 差分法の概略（式 1）。出席は、ROI での合計と平均が以下の方法で計算した閾値（式 2）を上まっていたらカウントとする。

図 5. ROI を設定した写真式（1）White area

図 3. クラスの活発度の写真=- 89 -

𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒘𝒉𝒊𝒕𝒆 𝒑𝒊𝒙𝒆𝒍𝒔 𝒑𝒆𝒓 𝒐𝒏𝒆 𝒇𝒓𝒂𝒎𝒆
𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒂𝒍𝒍 𝒑𝒊𝒙𝒆𝒍𝒔 𝒑𝒆𝒓 𝒐𝒏𝒆 𝒇𝒓𝒂𝒎𝒆

×100 [%]

式（2）̅−Threshold＝𝒙∑𝒏̅)𝟐𝒊=𝟏 √(𝒙𝒊 −𝒙𝒏𝒙𝒊 =SUM,AVERAGE
2－2. 第 2 プロジェクト
第 2 プロジェクトでは生徒は生徒が事前に作った Youtube を視聴する授業、B4、M1、M2 のそれぞれの生徒のプレゼンテーションを聞く授業の合
計三時間程度、四つの授業を受けた（図 6）。
白ピクセルの数の合計がクラスの活発度とする。

図 8. 元の写真教室が積極的だと白ピクセルの数は増える。
（図 7）
四つのクラスの白ピクセルの合計違いを比べた。

図 6. 授業の概要

図 9. 差分法を用いた写真

図 7. 白ピクセルのカウント
3. 結果と考察
3－1. 第 1 プロジェクト
第一プロジェクトでは、白ピクセルの合計と、平均両方で、出席を取れたと言える。座席番号 2番、8 番、11 番、14 番、20 番は閾値を超えていな
いため欠席と判断された。図○からもわかるように実際に彼らは欠席のため出席を取ることがで

図 10. 各座席の ROI の白ピクセルの平均きたと言える。欠席している生徒の ROI の値が多少あるのは、出席している生徒がその ROI に入っているからだと考える。加えて、一つ問題がある。
もし金髪の方がいると出席を取るのが難しい。以下の二つの図は、上の図が元の写真（図 8）、下の図は差分法を用いた後の写真（図 9）であるこれを見てもらうとわかるように、金髪の人のあたりで白ピクセルがほとんど現れていない。なぜならば、金のピクセルが持つ輝度は違いをほとんど持たないためであると考えられる。出席は動画の撮
影時間とプログラミングの解析の時間合計 3 分で取ることができた。

- 90 -

図 11. 各座席の ROI の白ピクセルの合計

図 14. 各カテゴリーの白ピクセルの量

図 12. 出席のカウント

4. 展望
このシステムは小学校、中学校、そして高校で3－2. 第 2 プロジェクト
第 2 プロジェクトではプログラミングによって使われる、特に活発的な授業の多い小学校では必出された結果と、授業後に生徒に書くように頼ん要とされるだろう。また、今回の出席は立命館大

だアンケートを比べた。生徒は YouTube を見る授学で取ったので、次は立命館高校で取る必要があ

業が一番興味を持って聞いていたと回答したが、る。このシステムを使った後は、先生は生徒がど

結果によると、M4 のプレゼンテーションの授業がのように感じたかのフィードバックを得る必要

最も多くの白ピクセルの値を表示している。理由がある。

としては、YouTube は動画を見ているだけなので生徒はほとんど動くことはないが、プレゼンテー

5. 謝辞

ションでは生徒は質問を考えたり、プレゼンテー

ご指導していただいた立命館大学理工学部ロションの準備をする必要があったりしたためだ

ボティクス学科生体工学研究室の岡田志麻教授、と考える。また座席以外のところで生徒だけでな

文本要氏、山本一天氏、CHOU QIANXU 氏に、このく、先生も動いていたためそれも結果に影響して場を借りて厚く御礼申し上げます。

いた。先生はこれらの結果を用いて次の授業の計
画を立てることができると考える。

6. 引用文献•

National Institute for
Educational Policy Research.
2018.The Work Environment of

Teachers in Japan
https://www.nier.go.jp/English/educationjapan/pdf/20180816WEJT.p
df•

Alexander Wettstein.Sandra
Schneider.Martin grosse
Holtforth.Roberto La Marca.2021.

図 13. 主観アンケートの結果

Teacher Stress: A
Psychobiological Approach toStressful Interactions in theClassroom- 91 -

https://doi.org/10.3389/feduc.20
21.681258•

Pystyle.2020. OpenCV – 背景差分
で物体を検出する方法について[How to detect objects bybackground subtraction].
https://pystyle.info/opencvbackground-substraction/•

Development of a non-contact
sleep monitoring system forchildrenhttps://www.frontiersin.org/articles/10.3389/fdgth.2022.877234/f
ull- 92 -

Development of a Student Status Estimation System for High School Classrooms

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
Japan is one of the countries which has problems with teachers being overworked. This aims to
reduce teachers’ burden by instantly taking attendance and visualizing the activity level. In thisresearch, Different Image Processing was used. It shows the difference between frames in a video.
At the beginning of the class, students were asked to wave their hands, shake their heads, etc, andROI, Region of Interest, was set to take attendance. The class consists of 4 phases for 3 hours.
These were compared. Attendance could be taken within 3 minutes. It takes a video for 1 minuteand analyzes it in 2 minutes. The class activity and subjective questionnaires were compared but
didn’t match. It is considered that the reason for this is because students were just watching movies
for the YouTube activity, whereas the others, they were thinking about questions or preparing
presentations. It was possible to help teachers because attendance could be taken, and teachers
could compare the results and use them for the next class. The next planned test will be done in aclass at Ritsumeikan High School.
Keywords: cars, tire grooves, splashed water, pedestrians, sidewalks- 93 -

I. Introduction
Japan is one of the countries which have problems with professor's overwork. In 2021,
68.2% of elementary school and 63.3% of middle school teachers in a nationwide survey of
public elementary and middle school teachers said they had wanted to quit teaching in the past
two years. In order to reduce this burden on teachers as much as possible, we will build a systemthat automatically checks attendance with the first project and visualizes the level of classactivity with the second project. In this system, teachers take images of the classroom with acamera previously prepared at the start of class, and the program automatically analyzes theimages. Then, the attendance of students is taken, and the level of activity is visualized. Thissystem can shorten the five-minute attendance time at the beginning of class, decreasing theteachers' business workload. In addition, class time can be secured, and classes can be taught
more efficiently. In addition, by visualizing the level of class activity, it will be easier to improveclasses throughout the class. This system will be used at Ritsumeikan Junior and Senior HighSchools and various other school facilities. In the system, the final goal is to easily offer the
information through applications such as smartphones and tablet PCs.
II. Materials and Method
This study used a technique called the Difference Image Processing (Figure 1). Video hasframes and images have pixels. This technique can represent motion as white and black pixels(Figure 2) in an image based on the difference in luminance of all pixels from frame to frame. It
is not counted if the difference in pixel-by-pixel luminance value is smaller than the difference inpixel-by-pixel luminance value in noise. The higher the activity level of the class, the higher thepercentage of white pixels, and vice versa (Figure 3). The experimental subjects were 25
university students. The experiment was conducted in Seminar Room 2, School of Mechanical- 94 -

Ritsumeikan University Biwako-Kusatsu Campus, Ritsumeikan University. The difference
image processing was used with an iPhone13 (version iOS 16.1.1) (Figure 4), a PC (VAIO
Windows 9), and Python as a programming language. The iPhone was set up near the ceiling on
the front wall of the classroom. This is so that all students' faces can be seen on the camera. The
video of the class was analyzed using the Difference Image Processing, and the results were
presented as data consisting of black and white. White pixels detected by the difference image
processing detect areas where objects are moving. In the first project, I asked students to wave
their hands and shake their heads, etc. At the start of the class a-minute video was recorded. ROI
was manually installed on the image previously to identify students in seats (Figure 5), and if thedifference in pixel- by pixel luminance was large in predetermined ROI (Region Of Interest), it
was determined that the student was in attendance. For the analysis method, ROI were set foreach seat, and the difference in luminance within each ROI was calculated. Attendance wascounted if the total percentage of white area was above the threshold value, or the average wasabove the threshold value calculated by the following method. (Figure 6).
Different image processing
𝐼𝑑 (𝑥, 𝑦)= 𝐼𝑛 𝑥, 𝑦 − 𝐼𝑛 −1 (𝑥, 𝑦)𝑥, 𝑦：Position coordinates in image
I：Luminance in the image (0-255)
Fig.1 Different image processing

Fig.2 Visual summary of different image processing- 95 -

Fig.3 Image of class activity

Fig.4 How the camera was set

Threshold＝𝒙 −𝒏𝒊=𝟏(𝒙𝒊 −𝒙)𝟐𝒏𝒙𝒊 =SUM,AVERAGE
Fig.5 Image with set ROI

Fig.6 How to set the thresholdIn the second project, Students took part in a spontaneous class and were videotaped doing
so for 3 hours. The amount of student activity varied by class content. There are 4 classes,(Figure 7) Class A, Class B, Class C and Class D. In class A, students watched a YouTube video
they made. For the rest, Class B, C and D, they delivered presentations. Class B consisted of 4thyear bachelor students. Class C consisted of 1st year master’s students, and class D consisted of
2nd year master’s students. The total number of white pixels was the activity amount. If the class
was positive, the ratio of white pixel increases. (Figure 8) The 4 different classes were compared.
Subjects answered the subjective questionnaire after all lectures. The method of questionnaire
was 10 level answer style. The topic was “whether you joined classes subjectively and actively ineach class.” The validity of the class activity level was evaluated by comparing the subjective
questionnaire and the results. The validity of the class activity level was evaluated.

- 96 -

Fig.7 Overview of measurement flow

Fig.8 White countIII. Results and Discussion
In the first project, Figure 9 shows the attendance or non-attendance. There are 3 graphs in
Figure 9. The top left graph shows the sum of white areas in all frames, and the top right graphshows the average of white areas in all frames. The orange line is the threshold. In addition, thebottom graph shows the attendance. If a student was determined as an absent, the value of thestudent was 0. If the student was present, it is 1. in both total and average, attendance could betaken. The student number 2, 8, 11, 14, 20 are determined to be absent because they didn’t
exceed the threshold. (Fig. 9) In the second project, the questionnaire that students answered andthe results by the method were compared in Figure 10. Figure 10 shows the subjective activity
level and the objective activity level. The left graph shows the subjective activity level in eachcategory. On the other hand, the right graph is the objective activity level in each category. In
both graphs, the blue one is from students watching YouTube videos. The orange one is fromthem listening to presentations by 4th year bachelor students. The grey one is from them listening
to presentations by 1st year master’s students. The yellow one is from them listening
presentations by 2nd year master’s students. Students answered that class A was the most- 97 -

interesting. However, the result shows that class B showed the largest amount of white pixels. Inclasses C and D, they almost didn’t move (Figure 10).

Fig.9 Attendance or non-attendance

Fig.10 Subjective activity level and objective activity level

In the first project, the movement of present students shows up in the ROI of absent
students. That’s why the value of absents has a little bit. In addition, there is one problem. If
there is a student with blond hair, it’s hard to take attendance. The right image is the original
image, and the left image is the image that uses Different Image Processing. (Figure 11) It
doesn’t show any white pixels. This is because the difference in blond doesn’t have so muchdifference to that one in white. Attendance could be taken in a total of 3 minutes for the video- 98 -

recording time and programming analysis time. In the second project, the results and thequestionnaire were different. This is because, for the class A activity, students were justwatching movies, whereas for the others, they were thinking about questions or preparing
presentations. Furthermore, not only students, but also teachers were moving. In addition,
presenters were moving forward to do presentations. These affected the results. Students
answered the same value as class B in classes C and D, but the results didn’t show the value.

Fig.11 Original image (L) and difference image processing image (R)IV. Conclusion
In the first project, attendance could be taken by taking video and ROI for each seat within
3 minutes, so it was done instantly. Based on both total and average calculations, five people inseat numbers 2, 8, 11, 14, and 20 were determined to be absent because they did not exceed thethreshold. This system could help teachers. In the second project, the activity level acrossdifferent categories were compared by applying Difference Image Processing to the entire
classroom. After each class, teachers can simply look at the results and use them to plan for the
next class.
V. Future Research
In the first project, this system needs to be improved in how to set the camera so thateveryone’s face can be seen in it. This system will be tested in all elementary, middle, and highschools in the future. Increased motion and activity, especially from elementary students, is- 99 -

expected and will need to be accounted for. To begin with, the next planned test will be done ina class at Ritsumeikan High School. In the second project, after using the system, teachers will
be asked to complete a survey asking them how they feel its use has affected their classes and forany other feedback that could be used to improve it. The class activity level was measured foreach category, but it is planned to make a graph chronological order. In this research, students
answered how they concentrated on lectures and how they get interested in them after all of it.
There is a time-lag, so it’s hard to comprehend how students feel. The next plan is going to be to
get data related to the direction of students’ faces and heart rate.
VI. Acknowledgements
The project would not have been possible without the help of my advisors: Professor
Shima Okada, Kanaru Fumimoto, Kazutaka Yamamoto, and Chou Qianxu from the BiophysicalEngineering Lab at Ritsumeikan University contained within the Department of Robotics,
Faculty of Science and Engineering.
VII. References
National Institute for Educational Policy Research. 2018.The Work Environment of Teachers inJapan https://www.nier.go.jp/English/educationjapan/pdf/20180816WEJT.pdf
Alexander Wettstein.Sandra Schneider.Martin grosse Holtforth.Roberto La Marca.2021. Teacher
Stress: A Psychobiological Approach to Stressful Interactions in the Classroom
https://doi.org/10.3389/feduc.2021.681258
Pystyle.2020. OpenCV – 背景差分で物体を検出する方法について [How to detect objects bybackground subtraction]. https://pystyle.info/opencv-background-substraction/
Development of a non-contact sleep monitoring system for children
https://www.frontiersin.org/articles/10.3389/fdgth.2022.877234/full- 100 -

Development of a Student Status Estimation
Ritsumeikan High School
System for High School Classrooms
ABSTRACTJapan is one of the countries which has problems with teacher’s being overworked. This aims to reduce teachers’ burden by instantly taking attendance and visualizing the activity level. In this research, Different Image Processing wasused. It shows the difference between frames in a video. At the beginning of the class, students were asked to wave their hands, shake their heads, etc, and ROI, Region Of Interest, was set to take attendance. The class consists of 4phases for 3 hours. These were compared. Attendance could be taken within 3 minutes. The class activity and the subjective questionnaires were compared, but they did not match. It is considered that the reason for this is because
students were just watching movies for the YouTube activity, whereas for the others, they were thinking about questions or preparing presentations. It was possible to help teachers because attendance could be taken, and teachers cancompare the results and use them for the next class. The next planned test will be done in a class at Ritsumeikan High School.

INTRODUCTIONANALYSIS METHOD

Background Japan is one of the countries which has problems with teachers being overworked. In 2021,

68.2% of elementary school and 63.3% of middle school teachers in a nationwide survey of public
elementary and middle school teachers said they wanted to quit teaching during the past two
years.
The
purpose of this study is to reduce the burden on teachers by instantly taking attendance (①PurposeStudent Attendance) and visualizing the activity level (② Class Activity Level). The goal is to makeit easy to improve the class by getting feedback and protect the privacy of the students by nothaving to use facial recognition.

① Student Attendance
Set ROI for each seat (Fig. 5) and calculated the difference in luminance within each region.
Attendance was counted if the total percentage of white area was above the threshold value or the average
was above the threshold value.
𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒘𝒉𝒊𝒕𝒆 𝒑𝒊𝒙𝒆𝒍𝒔 𝒑𝒆𝒓 𝒐𝒏𝒆 𝒇𝒓𝒂𝒎𝒆
White area =×100 [%]
𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒂𝒍𝒍 𝒑𝒊𝒙𝒆𝒍𝒔 𝒑𝒆𝒓 𝒐𝒏𝒆 𝒇𝒓𝒂𝒎𝒆

Threshold＝ഥ
𝒙−

σ𝒏
𝒙)𝟐
𝒊=𝟏 (𝒙𝒊 −ഥ𝒏𝒙 =SUM,AVERAGE𝒊② Class Activity Level
Compared the difference in pixel-by-pixel luminance values in each of the four time periods for the entire
classroom.

METHOD
TheoryRESULTS AND DISCUSSIONS

Different image processing
𝑰𝒅 (𝒙, 𝒚)= 𝑰𝒏 𝒙, 𝒚 − 𝑰𝒏−𝟏 (𝒙, 𝒚)① Student Attendance𝑥, 𝑦：Position coordinates in image
I：Luminance in the image (0-255)↑high activity
low activity↓
The activity level
decreases as timegoes onResult ①

If the difference in pixel-by-pixel luminance value issmaller than the difference in pixel-by-pixel luminancevalue in noise, it is not counted.

Average of white area in all frames

Sum of white area in all frames
Fig. 2 Summary of different image processing

Attendance

Measurement Method

1:attendance 0:non-attendanceFig. 1 Image of class activity

Ceiling

Subjects：25 university students
Location：Seminar Room 2, School of MechanicaliPhoneRitsumeikan University Biwako-Kusatsu Campus
Battery
Measurement device：One iPhone12 (Fig. 3)
Measurement objects：Subjective questionnaire(Visual Analogue Scale),Fig. 3 How to fix the camera
Video of the classroom (1920×1080 pixels, 30 FPS)
Experimental conditions：Given the predetermined seating arrangement in the high school
the region of interest (ROI) in the images was set accordingly.

Total percentageof white pixels in
1800 ROI images

1
0.8
0.6
0.4

0.2
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Average of thepercentage ofwhite pixels in
1800 ROI images

Seat NO.

Fig. 7 Attendance or non-attendance

Discussion ①••① Student Attendance

1.2

The movement of present students shows up in the ROI of absent students.
If there is a person with blond hair, it is hard to take their attendance.

Students were asked to wave their hands, shake their heads, etc. at the start of class and a 1-minute video
was recorded.
② Class Activity Level
Students took part in a spontaneous class and were video-taped doing so for 3 hours.
The amount of student activity varied by class content.
*1：4th year bachelor students*2：1st year master’s students*3：2nd year master’s students

Class A：The reaction of watching YouTube video
Class B, C, D：The reaction of watching 𝑩𝟒∗𝟏 , 𝑴𝟏∗𝟏 , 𝑴𝟐∗𝟏 ’s
presentation

Measur
ement
start

Class
A

Class
B

Break

Break

Class
C

Break

Class
D

Measurement
end

Fig. 8 Image and difference image② Class Activity Level

Result ②

Fig. 4 Overview of measurement flow
pointsSettings

Ratio (%)

① Student Attendance
The difference in pixel-by-pixel luminance was large in predetermined ROI (Region Of Interest).
→ Counting attendance

ROI Settings
26

25
19
1

27

15
9

8

3
1

28

21

14

13

7

20

29

30

22
16

23

11

5

2

Fig. 9 Subjective activity level and objective activity level

Positive activity

Discussion ②

18

17

4

Passive activity

24

10② Class Activity Level
The total number of white pixels was the activity
amount.

12

•
6

•

1

Fig. 6 White countFig. 5 Image with set ROI

For the class A activity, students were just watching movies, whereas for the others, they werethinking about questions or preparing presentations.
Not only students, but also teachers were moving. In addition, presenters were moving forward to
do presentations. These affected the results.

CONCLUSION① Student Attendance：Attendance could be taken by taking video and ROI for each seat.
② Class Activity Level：The activity level could be compared by category by calculating difference image processing• In both the total and average, five persons in seat numbers 2, 8, 11, 14, and 20 were determined tothe entire classroom.
be absent because they did not exceed the threshold.
• After every class, teachers can simply look at the results and use them to plan for the next class.

FUTURE PLAN

① Student Attendance：This system will be tested in all elementary, middle, and high schools in the future. Increased motion and activity, especially from elementary students is expected and will need to beaccounted for. To begin with, the next planned test will be done in a class at Ritsumeikan High School.
② Class Activity Level：After using the system, teachers will be asked to complete a survey asking them how they feel its use has affected their classes and for any other feedback that could be used to
improve it.

REFERENCES• National Institute for Educational Policy Research.2018.The Work Environment of Teachers in Japan
https://www.nier.go.jp/English/educationjapan/pdf/20180816WEJT.pdf• Alexander Wettstein.Sandra Schneider.Martin grosse Holtforth.Roberto La Marca.2021. Teacher Stress: A Psychobiological Approach to Stressful Interactions in the Classroom
https://doi.org/10.3389/feduc.2021.681258• Pystyle.2020. OpenCV – 背景差分で物体を検出する方法について [How to detect objects by background subtraction]. https://pystyle.info/opencv-background-substraction/• Development of a non-contact sleep monitoring system for children https://www.frontiersin.org/articles/10.3389/fdgth.2022.877234/full

ACKNOWLEDGEMENTS
The project would not have been possible without the help of my advisors: Professor
Shima Okada, Kanaru Fumimoto, Kazutaka Yamamoto, and Chou Qianxu from the
Biophysical Engineering Lab at Ritsumeikan University contained within the Departmentof Robotics, Faculty of Science and Engineering.

フルートの音色の物理的解析方法

要旨
この研究は、フルートの音色を物理的に解析するものである。演奏する際に用いられる主要な技
術を数値として抽出し分析した。主要な技術を「楽器がどれだけ鳴っているか」、「感情の音楽的表
現」の 2 つに分類し、それぞれ実験を行って分析した。実験においては、WaveSpectra（PC ソフトウェア）でフルートの音を分析することで波形・倍音のデータを得た。１つ目の実験では、初心者と熟練者の音の違いは、「楽器がどれだけ鳴っているか」の違いであり、何らかの物理的な要素に現れると仮定して実験を行った。その結果、倍音のバランスと音の強度に違いがみられ、いずれも低音を演奏した際に顕著にあらわれた。初心者のデータでは、鳴っている倍音のうち高い音域のもの
が雑音(ノイズ)に埋もれていたことに対し、経験者のデータでははっきりと倍音を確認することができた。また、高い倍音になる程強度が小さくなっていくが、その強度の変化が熟練者のデータの方が滑らかだった。２つ目の実験では、表現による音色の違いに着目した。感情を歓喜、激怒、嘆き、愉快の 4 つに分類し、それぞれをイメージした音を出して実験を行った。この実験では、ポジ
ティブな感情同士とネガティブな感情同士を比較すると、感情の方向性によって波形に違いが生まれるのではないかと仮定し、分析を行った。その結果、倍音のバランスと大きさが感情によって違うことがわかった。
フルート歴 1 週間）の違いがどのようにデータと

1. 背景
楽器の演奏において、私たちは１つの音を聞いして現れるのか実験した。まず、WaveSpectra でただけでもプロ奏者のような熟練者と初心者の音

各奏者の高音（E、1324 Hz）と低音（E、662 Hz）

を聞き分けることができる。この違いはどこからを測定・強度と周波数をデータ化した。その後、生まれているのか疑問に思い、研究を始めること鳴っている倍音の数と強度のバランスに焦点を当にした。本研究では、フルートの音色を「楽器がて、各奏者に見られる特徴を分析・比較した。

どのように鳴っているか」と「感情の音楽的表現」という２つの観点に分け、倍音に焦点を当てて物2－2. 感情表現

理的解析をおこなった。熟練者と初心者の音の違

歓喜、激怒、嘆き、愉快の 4 つの感情（喜怒哀楽

いのような、感覚的に捉えられることが多い音楽に基づくもの）について、それらを表現したときの事象を、データを分析することで、より理論的にデータ上でどのような違いが生じるのか分析しに解明することを目的としている。また本研究結た。まず、それぞれの感情と比較のための”ノー果を踏まえて、特に初心者にとっての、優れた奏”の 5 種類をラ（A、マル（感情表現をしない状態）者になるための練習方法の開発や、演奏技術の習884 Hz）の単音で表現し、WaveSpectra で測定・得の一助となることを目指したい。

強度と周波数をデータ化した。その後、倍音に焦点を当て、各感情表現に見られる特徴を分析・比
較した。

2. 方法
2－1. 熟練者と初心者の違い
熟練者（桐山、フルート歴 7 年）と初心者（中西、- 102 -

図 4. 低音（初心者）
3. 結果と考察(1) 倍音の数について

3－1. 熟練者と初心者の違い
図１、図２は、高音(E 1324Hz)を鳴らした際のここでは図１と図 2、図 3 と図 4 のように熟練

WaveSpectra の画面である。縦軸が音の強度であ者と初心者のデータの比較を行った。倍音のピー

り、横軸が周波数である。

クが鮮明にできていることを、倍音が鳴っている

熟練者、初心者に共通して、画面上の特定の周ことの基準とした。熟練者のデータでは、高音、波数でピークが複数見られた。このピークがフル

低音のどちらにおいても初心者のものよりたくさートの発する音波の中で強度が特に高く、私たちんの倍音が確認できた。
基音からより離れた、高い(周波数の大きい)倍の耳に聞こえてくる音であると考えられる。
楽譜に示される音を基音といい、図１、図 2 を音が、初心者のデータでは周りの雑音に含まれて分析した結果、最も強度の高い左端のピークの周見分けられないことに対し、経験者のデータでは基音が最も強度
波数は 1324Hz であったことから、ピークがはっきりと確認できた。この傾向は高音が高く、同時に鳴る倍音は、周波数が基音から離よりも低音の方が顕著に確認できた。

れるほどに強度が下がる傾向が見て取れる。
図 3、図 4 は低音(E 662Hz)を鳴らした際の画面考察として、高音に比べ、低音の方が多くの倍である。図 1、図 2 との比較をすると、高音より音を鳴らすために、音を出す際の息のコントロー

も低音を鳴らした際の倍音の数が多いことが分か

ルが難しく、明確な違いがみられたのではないかる。基音が最も強度が大きく、そこから周波数がと考える。

離れるにつれて倍音の強度が小さくなる傾向は共(2) 倍音の強度について通のものであることが分かった。

倍音の強度に関しては、先述の通り、基音から周波数が離れるにつれて小さくなっていくという傾向が見られたが、私たちは、この強度の減衰傾向に着目した。
基音の強度(dB)を最大の 100 として、他の倍音
図 1. 高音（熟練者）※縦軸：dB、横軸：kHzの強度を基音と比較して 100 分率で表すことで初
心者と経験者を比較した。つまり基音に対する他の倍音の強度のバランスを数値化し図５、図６に示した。それぞれの図において、熟練者は青色の

図 2. 高音（初心者）

マーカー(skilled)、初心者は橙色のマーカー(beginner)と示してある。近似曲線は熟練者のデータのものである。
図５(基音が高音の場合)を見ると、熟練者のデータは 1 次関数的に強度が変化していることが分

図 3. 低音（熟練者）

かるが、初心者は 4000Hz 以降の倍音の強度が不規則であり、明らかな差を見て取ることができる。
図６(基音が低音の場合)では、多くの倍音があったためか、
初心者のデータのばらつきが大きく、各倍音の強度が不規則に分布していた。それに対- 103 -

して熟練者のデータは、基音を最大として他の倍音の強度が対数的に近似できることが分かった。

図 7. ノーマル

図 8. 歓喜図 5. 各奏者の基音に対する他の倍音の強度比較

図 9. 激怒図 6. 各奏者の基音に対する他の倍音の強度比較
図 10. 嘆きこれらのことから、熟練者ひいてはプロの演奏する音は、基音を最大として低音域から高音域にかけて倍音の強度がより滑らかに変化していくことが特徴で、私たちが 1 音だけでも初心者との違いを聞き分けられるのはこれが原因ではないだろ

図 11. 愉快うか。この実験結果はサンプル数が少ないため、初心者と熟練者の双方のデータを増やしていくことが望ましい。そうすれば初心者や練習者は、自己の演奏の倍音の強度を観察する等、より客観的な要素を用いて練習を工夫できるようになるだろ
う。

激怒

嘆き

図 12．激怒と嘆きの比較
３−２．感情表現
図 7〜１１は、A（８８４Hｚ）を鳴らした際の（1） ポジティブな感情について

WaveSpectra の画面である。それぞれ、ノーマル

ポジティブな感情として、歓喜と愉快を比較し（感情表現をしない状態）、歓喜、激怒、嘆き、愉た。しかし、今回の実験結果からは大きな違いは快を表現した。実験 1 と同様に、倍音の数と強度見られなかった。言葉の定義やイメージが明確でに違いがみられた。

なかったことによるものだと考えられる。また、いくつか見られた違いについては、瞬間ではなく- 104 -

少し長い時間で見た際の変化であった。時間によ激怒は非常に外交的な感情で、嘆きは内省的な感る倍音の変化の比較については、これからの課題情である。このイメージが息のコントロールに影としたい。

響しているという仮説を立てた。先述の実験結果
でも同様の特徴が見られる。この仮説が正しけれ
ば、音楽による感情表現を客観的に判断し練習す（2） ネガティブな感情
ネガティブな感情として、激怒と嘆き比較を比る一助となるだろう。

較した。激怒のデータでは、倍音だけでなくその周りの音も大きいことが確認できた。一方、嘆き演奏者の練習に役立てるためには、他の感情やのデータでは、倍音のみが細い線で表示されてい今回あまり芳しい結果が得られなかったポジティ

る。この点について、激怒の場合は倍音の線が太ブな感情についてのより詳しい実験も必要となる。

いことに加えて円で示した倍音の前後の音が大き

また、実際に音を聞いた観客の感じ方とその音のく（図 12）、嘆きと比較して倍音のピークを頂点

データを比較し分析することにより、観客に効果とした三角形が大きいことが分かる。これらの倍的に感情を伝える演奏方法が明らかになるのでは音ではない音は、私たちの耳には雑音として認識

ないかと考える。

される。
雑音があることにより音に厚みが生まれ、倍音以外の観点からもデータを分析するなど、激怒という感情の荒々しさが表現されていると考よりたくさんの結果を得て考察を進めることが望

察した。

ましい。

また、嘆きのデータでは高い倍音が非常にはっきりと確認できる。一方、激怒のデータではこれ
らの高い倍音が雑音に含まれており、見分けるこ

4. 展望とができない。これは、奏者が嘆きという繊細なまずは多くの奏者のデータを集め、研究結果を

感情を表現するために、息を鋭く吐いてより綿密

より客観性のあるものにする必要がある。本研究にコントロールをしようとしたことによるものででは、フルートの音の違いについて倍音のみに焦はないかと考えられる。鋭い息とは、口を小さく点を当てて分析した。しかし、音を作る要素は他

すぼめて出すスピードの速い息という意味であり、にもあるため、何が違いを生む要因となっている

高い音を出そうとする際に使う。細かなコントロのかの詳しい研究が必要である。時間的要素によールがしやすいのが特徴である。逆に、激怒ではる変化の評価が目下の課題と考えている。また、口の中の空間を大きく開けて温かい息を吐くよう感情についての知識が不足しているため、よりたなイメージでゆっくりと息を吐いた。そのため、くさんの先行研究から情報を得て更なる実験を行

コントロールがあまりされず雑音の多い音になっっていきたい。加えて、フルート以外の楽器でもたとも考えられる。加えて、雑音が多いために高同様の実験を行い、どのような違いが出るのか調

い倍音がはっきりみられないことは、実験 1 の初

べていきたい。

心者の音にもみられた特徴である。
考察として、演奏技術が上がるにつれて、激怒

5. 謝辞のような雑音を多く含む音や嘆きのような倍音が2 年間の課題研究を通して、実験方法から考察ま

クリアな音をコントロールできるようになっていで終始的確な助言をくださった辻本先生に厚く御くのではないかと考える。

礼を申し上げます。また、実験に協力してくださ

また、これらの倍音の特徴は、感情の方向性にった同級生の皆さんに心から感謝します。本当による違いから生じるのものなのではないだろうか。 ありがとうございました。

- 105 -

6. 参考文献
牧勝弘（2016）「音の空間放射特性と音色～
楽器音解析とスピーカー設計を通して〜」
https://ipsj.ixsq.nii.ac.jp/ej/index.php?action=pages_view_main&active_action=reposito
ry_action_common_download&item_id=160400&it
em_no=1&attribute_id=1&file_no=1&pageid=13&
block_id=8 2022 年 9 月 15 日アクセス
ヤマハ株式会社 「アコースティックギターの振動・音響解析技術」
https://www.yamaha.com/ja/about/research/technologies/acoustic-guitar-analysis/ 2022 年
9 月 15 日アクセス
大石幸史・志民一成（2017）「音色評価のための音響分析方法の検討：倍音のもたらす心理的印象を焦点として」
https://shizuoka.repo.nii.ac.jp/record/8616/files/48-0213.pdf 2023 年 9 月 18 日アクセス
音楽の泉 「音階と周波数の関係（平均律一覧表）」
https://composer-instruments.com/scale-andfrequency/ 2023 年 10 月 28 日アクセス- 106 -

Method to Analyze Main Techniques of Flute Playing

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
This science project analyzed the primary techniques of flute playing, motivated by curiosity about
the recognizable differences between beginner and professional players. It was hypothesized thatthe key distinctions lie in the playing techniques and the expression conveyed. Techniques werecategorized into sound production and expression, with the latter assessed by the emotional
resonance of the melody. The study focused on the variation in sound corresponding to different
imagined emotions by the player. By examining how these factors influence the sound and overall
impression, the research aimed to guide beginners toward more efficient practice. Referencing
previous research on the relationship between sound pitch and wave direction in violin playing, apreliminary experiment on the flute was conducted. It revealed optimal sound projection in theflute's middle section, with no significant variation in sound pitch direction. Experiment 1
investigated the sound differences between beginner and professional players, identifying thenumber and balance of overtones as key differentiators. Experiment 2 explored the relationshipbetween sound characteristics and four emotions: Happiness, Violent Anger, Grief, and Enjoyment,
noting differences in overtones. This research contributes to understanding how players can makeflute playing more expressive.
Keywords: flute, technique, sound, expressive, pitch, overtone, emotion- 107 -

I. Introduction
This research is about the sound of the flute. The purpose is to consider whether thedifference of the sound data can be analyzed physically when we can recognize its difference.
The motive is to understand why one can recognize the difference between professional players'
sound and beginners' sound as a flute player. The main topic of this research is the difference
between professional players and beginner players. Also, the difference in sound data depending
on emotional expression is considered, too. If we could analyze them physically, beginnerplayers can get some information to be a better player from this research. If the sounds produced
by beginner and professional players could be analyzed physically, valuable information could
be obtained from this research, which could assist beginner players in improving their skills.
Previous research established a reference between the pitch of sound and the direction of
the sound waves heard when a violin was played. A preliminary experiment of the flute wasdone, and the sound was heard best from the middle part of the flute. There was no difference inthe direction of the sound pitch. In this experiment, the difference between a professional and a
beginner player could not be revealed, but the result can be utilized for the recording method.
II. Methods
Experiment 1 ~ Difference Between Skilled and Beginner Players ~This research is about the sound of the flute. The purpose is to consider whether thedifference of the sound data can be analyzed physically when we can recognize its difference.
The motive is to understand why one can recognize the difference between professional players'
sound and beginners' sound as a flute player. The main topic of this research is the difference
between professional players and beginner players. Also, the difference in sound data depending
on emotional expression is considered, too. If we could analyze them physically, beginner- 108 -

players can get some information to be a better player from this research. If the sounds produced
by beginner and professional players could be analyzed physically, valuable information could
be obtained from this research, which could assist beginner players in improving their skills.
Previous research shows the relationship between sound pitch and direction of the soundwaves heard when a violin was played was a reference. A preliminary experiment of the flute
was done, and the sound was heard best from the middle part of the flute. There was nodifference in the direction of the sound pitch. The difference between a skilled and a beginnerplayer could not be revealed in this experiment, but the result can be utilized and analyzed. This
research enables players to play the flute more expressively.
Experiment 2 ~ Expressing Emotions ~The analysis focused on understanding how the expression of emotions affects soundquality. Initially, the player conveyed four emotions: Happiness, Violent Anger, Grief, andEnjoyment, and these expressions were measured using WaveSpectra. The sound in a normal,
unemotional state was also compared. Subsequently, the characteristics of each emotional
expression were analyzed and compared, with particular attention to the overtones.

- 109 -

III. Results and Discussion
Experiment 1

Fig.1 High tone of the skilled player

Fig.2 High tone of the beginner player

Fig.3 Low tone of the skilled player

Fig.4 Low tone of the beginner player- 110 -

Fig.5 High tone

Fig.6 Low tone

Two features were identified as the key differences between the skilled player and the
beginner player: the number and the balance of overtones.
The number of overtones was larger in the data of the skilled player. In the data of the hightone of the skilled player (Fig. 1), the higher overtones are much clearer than in the data of the
beginner player. In the data of the beginner player, the tone that should be an overtone isincluded in the noise. This feature is more remarkable in the data of low tone (Fig. 3, Fig. 4). The
data of the beginner player has many lower overtones, but the number of higher overtones wasvery small. These tones were hard to recognize because they are similar to noises. It can bethought that these tones made the original sound unclear.
The second feature concerned the balance of overtones. In the skilled player's data, thevolume of overtones decreased as they got higher. For high tones, the skilled player's dataapproximated a linear curve, while for low tones, with more overtones present, the curve
resembled a logarithmic line. In contrast, the beginner's data (represented by orange dots)
showed fluctuating patterns, suggesting a smoother line for the skilled player's data.
This finding could be instrumental in guiding beginners to improve their playing.
However, this study was limited to just two players. Further data collection from additional
players is necessary to substantiate these results.

- 111 -

Additionally, it's generally believed that low tones are more challenging for beginners toplay beautifully, which this research supports by showing that low tones have more overtones.
Conversely, for skilled players, high tones are more challenging. This is evident in the data,
where the volume gap between the keynote and its next overtone is larger, particularly in hightones, suggesting that skilled players can better emphasize the keynote, which is morechallenging in high tones.
Experiment 2

Fig.7 Normal

Fig.8 HappinessFig.9 Violent anger- 112 -

Fig.10 Grief

Fig.11 Enjoyment

The second experiment measured the sound for four emotions: Happiness, Violent Anger,
Grief, and Enjoyment. To facilitate comparison, the sound in a normal state was also measured.
The overtones for each emotion were compared, but no significant differences were found. Thismight be because more than expressing different emotions through only one tone is required,given the importance of melody.
The emotions were classified into positive and negative categories. Happiness andEnjoyment are positive, while Violent Anger and Grief are negative. Although Happiness andEnjoyment were compared, no significant differences were found, indicating a need for further
research into positive emotions. It was hypothesized that the definitions of these emotions were
not clear enough.
However, some differences were observed in the comparison of negative emotions. In theViolent Anger data, the overtones around the larger ones were pronounced, and the line was- 113 -

thick, indicating some noise. This noise could be interpreted as expressing the roughness of theemotion. Generally, wind instrument players express anger by exhaling forcefully, and this result
is consistent with that technique. In contrast, the higher overtones were much clearer in the Grief
data than in Violent Anger. This might indicate that the player controlled their breath moredelicately to express Grief, possibly because Violent Anger is extroverted while Grief is
introverted. The study concluded that the data for each emotion depends on the emotional
direction.
IV. Conclusion
From this research, it can be concluded that physical analysis of flute sound is indeed
possible. A key finding is that the balance and number of overtones vary significantly based on
the player's skill level and emotional expression.
In Experiment 1, two primary differences between skilled and beginner players wereidentified: the balance and the number of overtones. The skilled player's graph displayed asmoother approximate curve than the beginner's. Additionally, the sound produced by the skilledplayer contained more overtones.
Experiment 2 revealed variations in sound related to emotional expression. Differenceswere noted in the amount of noise and the clarity of overtones. It is inferred that the direction of
the expressed emotion influences these variations.
V. Future ResearchFirst and foremost, further experiments should involve more players. Since this research
was conducted with only two players, obtaining more varied data is essential to validate ourhypothesis. Additionally, other factors influencing sound differences need to be explored. While
this study focused on overtones, other elements likely contribute to sound variation. In particular,- 114 -

the balance of overtones may reveal additional characteristics. For instance, the approximate
curve of high tones for the skilled player was a simple linear line in this study, but it might belogarithmic in the data of more skilled players. Creating a good approximate curve is morechallenging in high tones, possibly following a logarithmic pattern, which should be
investigated.
Furthermore, studying the sound of other musical instruments would be beneficial for abroader understanding. Research on emotional expression in music is a complex and somewhat
vague field, necessitating a deeper dive into existing literature. This study did not discern a clear
difference between Happiness and Enjoyment, indicating a need for more profound knowledge
better to understand the relationship between emotional expression and sound data.
VI. References
Maki, K. (2016, May 22). 音の空間放射特性と音色〜楽器音解析とスピーカ設計を通して〜 [Special Radiation Characteristics of Sound and Its Relation to the Timbre: Analysis ofMusic l Instruments and Design of Loudspeakers].
https://ipsj.ixsq.nii.ac.jp/ej/?action=repository_uri&item_id=160400
Ohishi, Y, Shitami, K. (2017, May). 音色評価のための音響分析方法の検討〜倍音のもたらす心理的印象を焦点として〜 [Study of Acoustic Analysis Methods for Evaluation of
Timbre: As Focus of the Psychological Impression by Harmonics]. 213−226.
https://shizuoka.repo.nii.ac.jp/record/8616/files/48-0213.pdf
音階と周波数の関係（平均律一覧表）[Relationship between the scale and the frequency(equal temperament table)]. (n.d.). 音楽力の泉. https://composer-instruments.com/scaleand-frequency/
Vibration and audio analysis of acoustic guitar (n.d.). Retrieved September 15, 2022, fromttps://www.yamaha.com/ja/about/research/technologies/acoustic-guitar-analysis/.

- 115 -

Method to Analyze Main Techniquesof Flute Playing

Ritsumeikan High School

Abstract
This science project analyzed the main techniques of playing the flute. The motive was that we wondered why we can recognize the difference between beginner and professional players. It is hypothesizedthat the main techniques of how the flute is played and the expression make us recognize the difference. The main techniques of flute playing were categorized by making sound and expression. Expression isdetermined by how the emotion is felt from the melody. We decided to research about the difference of the sound that the player imagined about each emotion. Also, vibrato is very important to express. By
revealing how these factors change the sound and impression, beginners can be more efficient player.Previous research shows the relationship between sound pitch and direction of the soundwaves heard
when a violin was played was a reference. A preliminary experiment of the flute was done, and the sound was heard the best from the middle part of the flute. There was no difference in the direction ofsound pitch. In experiment 1, we researched about the relationship between sound data and emotions. Emotions were divided to four emotions:Happiness, Violent anger, Grief and Enjoyment. There weresome differences in overtone. In experiment 2, the difference between beginner and professional player sound was researched. The number of overtones was the difference. This research enables players toplay the flute more expressively.

Introduction

Methods

This research is about sound of flute. The difference of data of sound depends on the emotional
expression played by the musician. This research looks at the logical reason why we can feel theemotion from music. Also, we can find ways to play the music more expressively.
Previous research shows the relationship between sound pitch and direction of the soundwaves heard
when a violin was played was reference. A preliminary experiment of the flute was done, and thesound was heard best from the middle part of the flute. There was no difference in the direction ofsound pitch. In this experiment, the difference between a professional and beginner player could not
be revealed, but the result can be utilized and analyzed. This research enables players to play the flute
more expressively.

1. Measured the sound A (884 Hz) of the flute with WaveSpectra. The waveform and overtone wasrecorded.
・Experiment 1
Measured the sound with four emotions: Happiness, Violent Anger, Grief, Enjoyment.
・Experiment 2
Measured the sound with two people: a skilled player (7 years) and a beginner player (one week).
2. Analyzed the relationship of data.

Experiment 1

Experiment 2
Results

Results
The expression technique was experimented by only one tone.
KeynoteOvertoneFig. 6 High tone of skilled player

Fig. 7 High tone of beginner player

Fig. 8 Low tone of skilled player

Fig. 9 Low tone of beginner player※Vertical axis: dB
Horizontal axis: kHz

Fig. 1 Normal

Table 5. The biggest overtones of high tone

Fig. 2 Happiness

Table 6. The biggest overtones of low tone

Fig. 3 Violent Anger

Number : % (dB)

Fig. 4 Grief
Fig. 5 Enjoyment
Fig. 2 ~ 5 are the data of sound: Normal, Happiness, Violent Anger, Grief, and Enjoyment.
We can see many overtones when the sound is expressed with emotion.
In Table 1, the overtones were compared only in each emotion. Table 2 is the information from aprevious research. Table 3 and Table 4 are the comparison of the data on each side, negative andpositive.
Table 1. Relationship between each emotion and overtones◎：−20~40 dB◯：−40~60 dB△：−60~80 dB

Table 2. Characteristic of each overtone

Table 3. Comparison of positive emotion

Table 4. Comparison of negative emotion

Discussion
First, we compared the overtones in each emotion. However, we could not find any big difference
from the data (Table 1). Since the melody is very important, only one tone is not enough to express
different emotions. We classified the emotions into negative and positive to find the difference inmore detail. We compared the two emotions on each side, negative and positive. In the previous
research, it is said that each overtone has a certain characteristic (Table 2). The relative result is Table
3 and Table 4. Happiness and Enjoyment were compared. However, this is not a big difference, so wehave to research more about the positive emotions. We hypothesized that the definitions of the words
were not clear. Violent anger and Grief were also compared. The characteristics of negative emotions
were clear. In the data of Violent Anger, the tones around big overtones were big and the line wasthick. This means that there was some noise. This can be thought that the noises express its
roughness. The noises made the sound complicated and heavy. On the other hand, in the data of
Grief, higher overtones were much clearer than those of Violent Anger. This result can be thought theplayer tried to control the breath by exhaling sharply to express Grief. We thought that is because
Violent anger is extroverted and Grief is introverted.

In Table 5, 6, Fig. 10 and
11, the volume of theovertones is displayed as
the percentage when we let
the volume of the keynote
be 100.

Fig. 10 High tone

Fig. 11 Low tone

Discussion
We found two features, the number and the balance of the overtones in the data of the skilled player.
The number of overtones were larger in the data of the skilled player. As you can see from Fig. 6~9,
the higher overtones are much clearer in the data of the skilled player. In the data of the beginnerplayer, the tones that should be an overtone are included in noise. In the data of low tone, thesefeatures are more remarkable. The data of the beginner player has many lower overtones, but the
number of higher overtones were very small. The lower tones are hard to recognize because they are
similar to noises. Also, so many tones other than overtones can be seen in the data. We thought thatthese tones made the original sound unclear.
The second feature is the balance. In the data of the skilled player, the higher the overtones become,the smaller its volume gets. However, the volume of overtones of the beginner player fluctuated. Fig.
10, 11 shows the result intelligibly. In Fig.10 (high tone), the approximate curve of the skilled player
was linear. In Fig. 11 (low tone), there were more overtones so the approximate curve does not
become simple linear. It became a logarithm. There is a possibility that the skilled player’s overtones
are on a smoother logarithm. The data of low tone also shows clearer results about this feature. Thisis a new discovery. By using this feature, the beginner player can get information to become a better
player. However, we did an experiment with only two players this time. So we have to collect otherplayer’s data to support this result.

Conclusions / Future Plan
In conclusion, the balance and number of overtones were the biggest difference depending on
emotions and skills. We learned the fact that tone color and expression is affected by overtone. As
our future plan, we have to find other factors. We researched only about overtones this time, but there
must be other factors. Also, the research about the sound of other instruments should be done.
Moreover, the research about emotions is very deep and the topic is vague, so we have to learn more
about previous research.

References
Maki, K. (2016, May 22). 音の空間放射特性と音色〜楽器音解析とスピーカー設計を通して〜 [Special Radiation Characteristics of Sound and Its Relation to the Timbre: Analysis of Musical Instruments and Design ofLoudspeakers]. https://ipsj.ixsq.nii.ac.jp/ej/index.php?action=pages_view_main&active_action=repository_action_common_download&item_id=160400&item_no=1&attribute_id=1&file_no=1&page_id=13&block_id=8
Vibration and audio analysis of acoustic guitar (n.d.). Retrieved September 15, 2022 from ttps://www.yamaha.com/ja/about/research/technologies/acoustic-guitar-analysis/
Ohishi, Y, Shitami, K. (2017, May). 音色評価のための音響分析方法の検討〜倍音のもたらす心理的印象を焦点として〜 [Study of Acoustic Analysis Methods for Evaluation of Timbre :As Focus of the Psychological
Impression by Harmonics]. 213−226. https://shizuoka.repo.nii.ac.jp/record/8616/files/48-0213.pdf
音階と周波数の関係（平均律一覧表）[Relationship between the scale and the frequency (equal temperament table)]. (n.d.). 音楽力の泉. https://composer-instruments.com/scale-and-frequency/太陽放射と近くの天体の反射スペクトルの比較要旨
この研究は Korea Science Academy of KAIST (KSA)との共同研究である。今年度から新たな KSAの生徒と一緒に研究を始めた。昨年まで行っていた研究で得た知識、能力を活かして行うことのできる新たな研究テーマを実際に KSA の生徒と対面し、決定した。KSA と立命館でそれぞれ観測し、結果を分析して共有しあうという方法で進めた。同じ研究テーマの中で KSA チームと立命チームで比べる天体が違い、そして実験内容や実験結果も異なった。私たちは太陽と月のスペクトルをそれ
ぞれ立命館の天体望遠鏡で観測し、比較した。またその比較結果からなぜそのような結果になったのか考察をした。結果からは、太陽と月のスペクトルは形状が異なるということが分かった。また、いくつかの吸収点が同じであった。そして月のスペクトルは太陽のスペクトルより小さいことが分かった。

1. 背景

物理学では、プリズムなどの分光器に光を通す

光のスペクトル分析は、光源に関する多くのと虹のような色帯ができる（光成分の波長によ情報を提供することができる。特に、吸収スペって屈折率が異なるためである）。スペクトルを

クトルを分析することで、光源やその周辺の元見れば、それぞれの光がどのような波長を持っ素に関する情報を得ることができる。本研究のているかが一目でわかる。

目的は、太陽光と、太陽反射である惑星や衛星

吸収スペクトルとは、ある物質が各波長の光をからの光のスペクトルを比較・分析すること

どれだけ吸収するかを表したグラフである。連続で、天体表面の組成を分析することである。天スペクトルを構成する光が冷たくて密度の低い体からの光は太陽光の反射であるが、地表や大気の組成などの原因によって、異なる太陽光と気体を通過すると、吸収スペクトルになる。

はスペクトルが現れると予想される。今回の研究を通して、宇宙空間にある天体から直接岩石を採取して分析しなくても、望遠鏡と分光器だ
けで宇宙空間の天体の表面成分を分析できる可能性のある結果が出ると期待している。本研究では、まず、月や太陽系惑星のスペクトルを取図 1.スペクトルの例 図 2.吸収スペクトルの例得した後、既知のベガのスペクトルと分光器か

最後にこの研究は Korea Science Academy ofら得たスペクトルを用いて、本来の太陽のスペ

KAIST (KSA)との共同研究である。今年度から新

クトル以外の物質や地球大気などの影響を除去

たな KSA の生徒と一緒に研究を始めた。昨年ましたスペクトルを取得する。そして、このスペで行っていた研究で得た知識、能力を活かしてクトルと太陽のスペクトルの比較分析を通じ行うことのできる新たな研究テーマを実際に KSAて、天体表面の成分を予測するプロセスを行の生徒と対面し、決定した。KSA と立命館でそれう。

ぞれ観測し、結果を分析して共有しあうという方法で進めた。

スペクトルとは、分光器に光を通し、電磁波の波長ごとの強度分布を記録したものである。

2.先行研究- 117 -

に、くり抜いた穴に電球を入れてスペクトルを測

2−1.背景私たちのチームは本テーマである太陽光と太った。今回の実験では LED とハロゲンの２種類の陽光が反射された月からの比較をする前に、先スペクトルを取り、部屋が明るい場合と暗い場合行研究として積分球の効用性について研究しの 2 パターン試した。次にやすりを使って積分球

た。積分球の中で光を乱反射させることでよりの内壁を擦ってから、カラースプレー（白色）を

均一な光を入手することができ、分光器の校正使って塗装した。その後、先ほどと同じように LEDができる。

とハロゲンを点灯した時のスペクトルを得た。そして積分球の内壁の塗装前と塗装後の二つの電先行研究として私たちは昨年度に直径 2m の積球のスペクトルを比較した。

分球を作った（図 3）。積分球は内面が球形で，内壁が硫酸バリウムなどの反射率の高い光散乱
素材で作られている。私たちは硫酸バリウムス

2−3.実験結果

プレーを積分球の内壁に塗った。これは取り込
んだ光(測定光)を散乱させ均一にする効果がある。そこで私たちは、この作った積分球の正確性を確かめるために、実験を行った。

図 4. LED 部屋の明るさの違いのグラフ
青：LED（塗装なし、明るい部屋）
オレンジ：LED（塗装なし、暗い部屋）
図 3.積分球
2−2.実験方法
積分球に光源を配置し、光ファイバーを積分球の中に付けることで積分球のなかを乱反射した均一な光は光ファイバーを通じ、コンピュータとデータを数値化する FLAME-S により数値としてコンピュータの中に得ることができる。まず初めに、実験室内の電気をつけた状態で実験を行い、次に図 5. ハロゲン 部屋の明るさの違いのグラフ

実験室内の電気をオフにしてデータを得た。本研
究の 1 番の狙いは、積分球として効用性を確かめられるかであるため。メインの実験として、LED ラ
イ トや 白熱電 球を 使用し 、コ ンピュ ータ 内のExcel を用いてグラフ化し可視化できるようにした。直径 2m の発泡スチロールからできた半球を繋ぎ合わせ、積分球を作成した。また、電球を通す穴をくり抜いた。しかし最初のこの実験では積分球の内壁にカラースプレーは塗っていない。次- 118 -

青：ハロゲン（塗装なし、明るい部屋）
オレンジ：ハロゲン（塗装なし、暗い部屋）

図 8.光ファイバー

図 9.分光器 FLAME-S

今回は 10 回ずつ測ったため Excel の機能を使用

図 6. LED 塗装有無 比較のグラフ

し、10 回の平均のグラフを作成した。

青：LED（塗装なし、暗い部屋）
緑：LED（塗装あり、暗い部屋）

3－2. 太陽と月のスペクトルの獲得と比較
まず、天気予報で観測に適した日を探す。その日は湿度が適切で、曇り空でなければならない。
なぜなら、データは周囲の環境からノイズを吸収してしまうからだ。次に、適切な日に太陽と月のスペクトルを観測した。そして、データをエクセ
ルにまとめ、異なるスペクトルのグラフを作成した。
最後に、
太陽と月の 2 つのスペクトルを重ね、図 7. ハロゲン 塗装有無 比較のグラフ違いを比較し、分析した。

青：ハロゲン（塗装なし、暗い部屋）
緑：ハロゲン（塗装あり、暗い部屋）

4.実験結果4－1. 太陽のスペクトル

2−4.考察オレンジ色のグラフは LED とハロゲンを点灯し、明るい部屋で実験を行ったものである。この結果
から LED からの光を取り込むには部屋を暗くしなければならないことがわかった。また、カラース
プレーは波長を滑らかにし、積分球にとってより適したものであることがわかった。これはこのカ
ラースプレーがより多くの光を乱反射させるためである。今回の実験により、作成した積分球をフラットフィールド補正に使用していきたい。
3.観測方法図 10.太陽のスペクトルグラフから、440 nm ,515 nm, 590 nm,
650 nm ,690 nm, 720 nm, 760 nm で吸収されていることが分かる。

3－1. 天体のスペクトルの獲得
天体観測には天体望遠鏡 （NISHIMURA FACTORY、
カセグレン式、口径 3000 mm）を使用した。光ファイバー（図 8）とオーシャンビュー社の分光器
Flame-S（図 9）を使用し、得られた光を定量化した。

- 119 -

〜490 nm の波長を示すため、太陽からの光が月を4－2. 月のスペクトル

通過することでこの部分の波長が減衰して、太陽に比べて凹んでいるのではないかと考えた。
5−2.考察 2
グラフより、月のスペクトルが 600 nm 付近で大きく凹んでおり、月の影響であると考えられる。
月には斜長岩同様に玄武岩も存在する。新鮮な玄武岩は黒色を示すが、酸化すると赤茶色を示す。
赤色というのは波長の 640 nm〜770 nm を吸収す

図 11.月のスペクトルグラフから、530 nm, 590 nm, 660 nm ,680

る性質を持つ。月には地球ほどではないが、酸素

nm, 710 nm, 760 nm で吸収されていることが分が存在している。これらのことより、長年の月日かる。

を重ねることで酸化したことがこの結果に影響しているのではと考えた。

4－3. 太陽と月の比較スペクトル5−3.考察 3
考察 2 のように玄武岩は酸化している可能性があるが、完全に酸化しているわけではなく、黒色を示す玄武岩と酸化した赤茶色の玄武岩が共存していると考えた。それに加えて、スペクトルは別日に取得していることもあるため、完全に同じ条件下ではないことや、近年の大気汚染などに少なからず影響を受けて細かなノイズが含まれていることが考えられる。
図 12.太陽と月の比較スペクトル
この結果から、月のスペクトルは太陽のスペク

6.展望

トルより小さい。これらは特に短い波長において今回の実験では太陽と月のスペクトルを比べは強度が変わることがわかる。また、750 nm で大なぜその波長で吸収されているのか、理由を考えきく吸収していることがわかる。いくつかの吸収た。しかしこの考察は私たちの考察なので正確で点が同じである箇所がある。

はないかもしれない。だから、今回の実験では納得のいく考察を得ることができなかったため、今後さらに天体について知識を深め、さらに正確な5.考察使用した分光器では、1000 nm あたりの波長の考察をしていきたいと考えている。また、太陽と詳細を詳しく得ることができないため、可視光

月だけではなく他の天体でスペクトルを比較し範囲の波長について注目することとした。

考察をしたい。月の光は太陽の光を反射している
ため同じスペクトルになるように思えるが、今回の実験で違うと分かった。なぜ異なる形状になっ

5−1.考察 1
400〜500 nm で月が光を吸収している。月の成たのか最終的な理由を考えたい。

分として多い斜長岩の色は暗灰色からは灰青色の色をしている。この青色は波長でいうと 430 nm

7. 謝辞- 120 -

本研究を進めるにあたり、お忙しい中ご指導いただいた笠巻奈月先生、市川美恵先先生、国際共同研究でお世話になった Korea Science
Academy of KAIST の Dr. In- ok Song に心より深く感謝申し上げます。また、積分球の作成にあたり助言をくださった立命館大学の佐伯和人
教授に熱く感謝致します。昨年度、今年度と共に研究をして来た Korea Science Academy of
KAIST の 6 人の仲間 Dong Hyeok Kim, Min Soo
Kim, Minhyuk Jeong, Minchan Kim, Yoonhong
Park, Seonghyeok Choi、執筆のご指導をいただ
いた先生方にも熱くお礼を申し上げます。みなさまのご指導があったからこそ私たちは本研究を進めることができ、知識を深めることができました。
8. 参考文献
1. スペクトルとは

https://www.klv.co.jp/corner/what-isspectrum.html
2. Fraunhofer lines

https://en.wikipedia.org/wiki/Fraunhofer_lines- 121 -

Comparison between Solar Radiation and Reflectance Spectrumof Nearby Astronomical Objects

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
Spectral analysis of light can provide much information about the light source. In particular, by analyzing
the absorption spectrum, it is possible to obtain information about the elements of the light source or its
surroundings. The purpose of this study is to analyze the composition of the surface of an astronomical
object by comparing and analyzing the spectrum of sunlight and light from planets or satellites, which aresolar reflections. Since the light from astronomical objects is a reflection of sunlight, it can be thought thatthe spectrum will not differ from that of the sun. However, the initial prediction was that different spectra
would emerge due to factors such as the composition of the surface or the atmospheric conditions. Throughthis research, there is anticipation of obtaining results that could potentially be employed to analyze thesurface composition of celestial objects using only a telescope and spectrometer, eliminating and analysis
for direct collection and analysis of rock samples from these objects. In this study, first, after obtaining thespectrum of the moon and the planets of the solar system, the known spectrum of Vega and the quantum
efficiency information of the spectrometer will not be used to obtain the real spectrum with the influenceof substances other than the original sun spectrum and the of the astronomical objects such as earth’s
atmosphere removed. Then, through a comparative analysis of this spectrum and the real spectrum of thesun, a process of predicting the components of the surface of the astronomical object can be conducted.
Keywords: spectral analysis, absorption spectrum, astronomical objects, Vega, atmosphere- 122 -

I. Introduction
This collaborative research project with the Korea Science Academy of KAIST (KSA)
compares the spectrum of the Sun and the Luna and analyzes the differences. The KSA teamused Vega's spectrum to obtain and analyze Saturn's spectrum. A spectrum is a record of theintensity distribution for each wavelength of electromagnetic waves obtained by passing lightthrough a spectroscope. In physics, a rainbow-like color band is created when light is passed
through a spectroscope such as a prism, because the refractive index differs depending on the
wavelength of the light component – arranged in order of wavelength.

Fig.1 Spectrum of sunlight (Ref.1)

Fig.2 Absorption spectrum

Broadly speaking, it is the decomposition of a certain composition, and the components arearranged by size. By looking at the spectrum, it can see briefly what kind of wavelength eachlight has. The absorption spectrum is a graph showing how much light of each wavelength isabsorbed by a substance. If light comprising a continuous spectrum passes through a cool, lowdensity gas, the result will be an absorption spectrum.

- 123 -

II. Materials and Method
An Astronomical telescope (NISHIMURA FACTORY, Cassegrain type, Caliber 3000mm)
was used to observe astronomical objects. Optic fibers and the spectrometer Flame-S of Ocean
View were used to quantify the obtained light. A computer was used to make the graph ofcollected data in Excel.

Fig.3 FLAME-S

Fig.4 Optic fibers

Fig.5 OtO spectrometer

First, weather forecasts were used to find days with suitable conditions. The day used forobservation needed to have proper humidity and be cloudless. That’s because collected data will
absorb some noises from the surrounding environment.
Second, the spectrum of the sun and Luna were observed on suitable days. Third, data wascompiled in Excel, and graphs were created for the different spectrums. Finally, the differences
between the two spectrums of the Sun and Luna were analyzed.
III. Data Analysis
In our experiment, the spectrometer couldn’t get the wavelength range of more than 1000
nm in detail. So, we tried to get the feature in the range of visible light and focused on the color.
The sun and luna spectrums were viewed on different days. Figure 6 shows spectrum of thesun, while Figure 7 shows spectrum of Luna. From these results, we can see different shapes.
Some absorption points are the same in places. As shown in Figure 8, Luna’s spectrum is smaller
than the sun's spectrum.

- 124 -

Fig.6 Sun spectrum data acquired on October 23, 2023, around 13:00 at Ritsumeikan High School(no clouds, good humidity)

Fig.7 Luna spectrum data acquired on September 29, 2023, around 19:00 at Ritsumeikan High School(no clouds, good humidity)- 125 -

Fig.8 Graph showing the spectrum data from the sun and Luna

IV. Discussion
Wavelengths of 400 nm to 500 nm
It is thought the lights that come from Luna to the earth absorbed the wavelengths in therange of 400 nm to 500 nm due to the plagioclase that exists on the surface of Luna. That’s
because the original color of Plagioclase is dark gray to grayish blue. (The blue color is absorbed
around the wavelength in the range of 430 nm to 490 nm.)Fig.9 Wavelengths of 400 nm to 500 nm

Wavelengths of Around 600 nm
This part of the spectrum data is thought to have been influenced by the presence of basalt
on the surface of Luna. Pure basalt is black in color. However, when basalt is oxidized, it- 126 -

changes from black to reddish brown. The reddish-brown color is similar to orange, which
absorbs wavelengths between 590 nm and 640 nm. This demonstrates oxygen is present on Luna,although not as much as on Earth. It is thought that the basalt has been oxidized for a long time.

Fig.10 Wavelengths of around 600 nm

Although it is thought that there is oxidized basalt as an explanation for Figure 10, it seems
that both oxidized and non-oxidized basalt are present on the Lunar surface. Also, the spectra
were not observed on the same day, so the two experiments were not performed under the same
conditions. This result may have also been affected by air pollution and other factors.
V. Conclusion
This research has shown that it is possible to analyze the composition of the atmosphereand surface by comparing the spectra of the sun and moon taken with telescopes andspectrographs. It was found that that the absorption line between 400 nm and 500 nm was
because of plagioclase, and the 600 nm absorption line was due to oxidized basalt. In conclusion,
we tried to use school equipment to study the atmosphere's composition on the Moon's surface.
This experiment showed that using spectroscopy makes it possible to recognize the componentsthat make up extraterrestrial bodies with simple equipment.
VI. References
スペクトルとは [What is the spectrum?] https://www.klv.co.jp/corner/what-is-spectrum.html- 127 -

Comparison Between Solar Radiation and
Reflectance Spectrum of
Nearby Astronomical Objects
Ritsumeikan High School¹, Korea Science Academy of KAIST²

Abstract
Spectral analysis of light can provide a lot of information about the light source. In particular, by analyzing the absorption spectrum, it is possible to obtain information about the elements of the light source
or its surroundings. The purpose of this study is to analyze the composition of the surface of an astronomical object by comparing and analyzing the spectrum of sunlight and light from planets or satellites,
which are solar reflections. Since the light from an astronomical object is a reflection of sunlight, it can be thought that the spectrum will not be different from that of the sun. However, our prediction was thatdifferent spectra would appear due to causes such as the composition of the surface or the atmosphere. Through this research, we are looking forward to getting a result that can possibly be used to analyze thesurface components of objects in outer space using only a telescope and a spectrometer without directly collecting and analyzing rocks from them. In this study, first, after obtaining the spectrum of the moonand the planets of the solar system, the known spectrum of Vega and the quantum efficiency information of the spectrometer will be used to obtain the real spectrum with the influence of substances other thanthe original sun spectrum and the surface of the astronomical object such as the earth's atmosphere removed. Then, through a comparative analysis of this spectrum and the real spectrum of the sun, a processof predicting the components of the surface of the astronomical object can be conducted.

Introduction
Spectrum is a record of the intensity distribution for each wavelength of electromagnetic waves obtained by passing lightthrough a spectroscope. In physics, a rainbow-like color band is created when light is passed through a spectroscope such as a
prism (because the refractive index differs depending on the wavelength of the light component). Arranged in order ofwavelength. Broadly speaking, it is the decomposition of a certain composition, and the components are arranged by size. Bylooking at the spectrum, it can see at a glance what kind of wavelength each light has.
Absorption spectrum is a graph showing how much light of each wavelength is absorbed by a substance. If light comprising acontinuous spectrum passes through a cool, low-density gas, the result will be an absorption spectrum.
Fig.2:Absorption spectrum (Ref.2)

Fig.1: Sunlight spectrum (Ref.1)

Experimental tools

Experiment 2 (KSA)

Rits-Astronomical telescope(NISHIMURA FACTURY,
Cassegrain type, Caliber 3000 mm)-Optic fibers-The spectrometer Flame-S of Ocean View
Fig.3:FLAME-S-Computer(Dynabook)-iPhone
KSA-Astronomical telescope (TAKAHASHI 8-inch refractor, FCT-200)-OtO spectrometer & Optic fibers-Computer-RSpec / Real-time Spectroscopy

MethodIntensity

Fig.5:OtO Spectrometer

Intensity

Fig.4:Optic fibers

Experiment 1 (Rits)

Intensity

1. The spectrum of Vega and Saturn was observed.
2. Using Rspec, a calibration factor was obtained according to the wavelength with the known
Vega spectrum and the Vega obtained in step1.
3. The Saturn spectrum was calibrated with the obtained calibration factor.
4. The absorption band of Saturn's spectrum was analyzed and were determined
the atmospheric compositions.
Exposure time=10s
Results
Calibration Factor
Reference Vega
Vega

Method
1.Weather forecasts were used to find days with suitable conditions.
Wavelength(Å)

Wavelength(Å)

2.The spectrum of the Sun and Luna were observed on suitable days.

Fig.13:Vega spectrum

Fig.14:Reference Vega

3.Data was compiled in Excel and graphs were created for the different spectrums.

SaturnCalibrated
SaturnWavelength(Å)

Fig.15:Calibration Factor

4.The differences between the two spectrums of the Sun and Luna were analyzed.

Intensity

Discussion
Fraunhofer Absorption Line

Wavelength (nm)Fig.8: Sun and Luna spectrums

Fig.7: Luna spectrum
Day：September 29th
Time : Around 7 pm
Place : Ritsumeikan High School
Condition : No clouds, Good humidity

Methane Absorption Line⑤④

These are different shapes.
The absorption points are same.
The luna’s spectrum is smaller than
the sun spectrum.

Intensity

Fig.6: Sun spectrum
Day : October 23rd
Time : Around 1 pm
Place : Ritsumeikan High School
Condition : No clouds,Good humidity

Wavelength(Å)

Fig.17:Calibrated Saturn

Intensity

Intensity

Intensity

Wavelength(Å)

Fig.16:Saturn spectrum

Wavelength (nm)Wavelength (nm)Day : September 18th
Time: Around 20:30
Place: KSA Observatory
Condition: No clouds, Good humidity

Intensity

Sun and Luna

Luna

Sun

Intensity

Exposure time = 100μs

Results

Discussion③②①

Wavelength(Å)

Wavelength(nm)Fig.9: wavelength that is range of 400
nm to 500 nm

Intensity

Intensity

Intensity

Fig.18:Fraunhofer Absorption Line

Wavelength(nm)Wavelength(nm)Fig.10: wavelength that is range ofaround 600 nm

Fig.11: Sun and Luna spectrum

In our experiment, spectrometer can not get the data that is range of more than
1000 nm in detail. Our experiment tried to get the features in the range of
Visible light and focused on the color .

Wavelength(Å)

Fig.19:Methane Absorption Line

Chart ④Fraunhofer lines (orange) appeared in the calibrated Saturn spectrum (blue).
→ This implies that the light originated from the Sun.
Chart ⑤The calibrated Saturn spectrum (blue) had absorption lines that are not identified as Fraunhoferlines (e.g. around 620 nm).
These lines fit well with methane's absorption lines (yellow).
→ Saturn's atmosphere contains methane.

Conclusions
Fig.12:Around condition(when we took Luna and Sun
spectrum)

Chart ①
The wavelength that is between the range of 400 nm to 500 nm was absorbed.
→ The effect by the plagioclase of Luna’s surface.
- The original color is dark gray to grayish-blue.
（The blue color is absorbed around the wavelength in the range of 430 nm to 490 nm)
Chart ②The wavelength that is in the range of around 600 nm.
→ The basalt oxidized for a long time.
- Basalt exists on the surface of Luna.
- Pure basalt is represented by a black color. But the basalt that is oxidized changes toa reddish brown from the black.
(The orange absorbs the wavelength that is range between the of 590 nm to 640 nm)→ Oxygen is present on Luna
Chart ③
It is mentioned that there is oxidized basalt in the explanation of Fig.10, but it seems thatboth oxidized and non-oxidized basalt are present on Luna surface. Also, the spectra were
not observed on the same day. This result is also affected by air pollution and other factors.

This research has shown that it is possible to analyze the atmosphere or the surface composition bycomparing the spectrum of the Sun, Moon, and Saturn, taken by using telescopes and spectroscopes.
For the moon we found out that the absorption line of 400 - 500 nm is shown because of plagioclase
and the 600 nm absorption line was due to oxidized basalt. Analyzing the calibrated Saturn
spectrum using Vega showed additional absorption lines other than the Fraunhofer absorption line,
which was Methane. However, because the school's equipment could only obtain the spectrum in thevisible light region, the spectrum in the IR region could not be compared. If it becomes possible tocompare IR spectra, it will be possible to compare more diverse elements.
In conclusion, we tried to find out the compostion of the moon's surface and Saturn's atmospherewith school equipment. Through this experiment found we use spectroscopy, it is possible torecongnize the components that make up the celestial bodies outside of Earth with simple
instruments.

References
Ref 1.スペクトルとは What is the spectrum?
https://www.klv.co.jp/corner/what-is-spectrum.html
Ref. 2 Fraunhofer lines
https://en.wikipedia.org/wiki/Fraunhofer_lines

Ref 3. Zou, Y.-L., Liu, J.-Z., Liu, J.-J., Xu, T. (2004). Reflectance spectral
characteristics of lunar surface materials. Chinese Journal of Astronomy andAstrophysics, 4(1), 97–104.
https://doi.org/10.1088/1009-9271/4/1/97
Ref 4. Berry, R. (2018). Student spectrophotometry of the planets: What worked
and what did not. Robotic Telescopes, Student Research and Education
Proceedings, Vol 1, No 1.
https://doi.org/10.32374/rtsre.2017.014

効果的かつ海の生態系を守る人工リーフの実用化について

要旨
昨年度の実験から,私たちが考案した新型人工リーフが旧型人工リーフよりも波による砂浜の侵食の低減に効果的であることが示唆された。しかし,未だ実用化に向けた様々な課題が残っているため,海の生態系や制作コストなど、より実用的な観点を考慮して研究を行うことにした。まず、人工リーフ上に着生した水草による砂浜の侵食の低減効果を調査する
ため、3D プリンターで作成したプラスチック製の人工リーフに水草のモデルを取り付け、人工リーフ表面に占める水草モデルの面積と波による砂の侵食面積の関係を測定した。その結果,水草の表面積が大きいほど浸食面積が小さくなることがわかった。次に、人工リーフを通る水面波の波高を変化させ、人工リーフの天端水深、表面の突起物の個数と配置パターンがそれぞれ、各波高の水面波にどのような影響を与えるかを測定し、エネル
ギーの増減を示す減衰率を算出した。天端水深と波高に関しては、水面波の波高が人工リーフに干渉する場合に特にエネルギーの減衰が確認されたが、一部の条件下ではエネルギーの増幅が見られた。表面の突起物の個数や配置パターンと波高に関しては、個数に応じて減衰率に影響があり、今のところどのような条件下でもその上限が約 7 割であることがわかった。さらなる改善には、突起物を加工しエネルギーを逃すような工夫が必要である。今回、水草が波の減衰に効果的であることがわかったが、人工リーフの素材であるコ
ンクリート上に生育できるのかを確認する必要がある。また今回は、人工リーフを通過前後する水面波の波高を比較しエネルギーを算出したが、それに加えて一定時間におけるエネルギーの総和という形で、人工リーフの効果を評価する必要がある。
1．背景観が保たれることや,潮の流れを遮らない

過去 15 年で日本列島の砂浜は全体の面というメリット有しており,ほかの防波堤よ積の約 13％を海岸浸食によって失っていりもメリットがはっきりとしている。しかる。政府はそれに対する対抗策として,防波し,人工リーフに関する論文を調べても,天堤の建設を進めている。防波堤には,水面端水深や天端距離に関することばかりで形上よりも高い離岸堤と呼ばれるものや,テ状に関する記載が少ないと感じた。そこでトラポット,人工リーフなどの種類があり,

私たちは,新たな形状を考案するために人

私たちはその中でも人工リーフに焦点をあ工リーフの研究を始めた。

てて研究を行うことにした。人工リーフと昨年度の研究では,一般的な形状の旧は,水面下に造成する構造物で,珊瑚礁の波型モデル(図 1)と吸音材の形状を模して考を打ち消す機能を模したものであるため,案された新型モデル(図 2)の海岸浸食への

海岸浸食の軽減が期待される,さらに,防波軽減率を比較し,新型モデルの方が効果的

堤などと違い水面下にあることによって景であることが示唆された。しかし,人工リ- 129 -

ーフを設置すること自体がそもそも海の生れを旧型と新型の両方で実験をしたため，態系に悪影響を与えてしまうことや,製造

計 6 パターンの人工リーフで砂の侵食面積

コストが高いことなどの問題点がある。そを測定し，効果を比較した。

れらの問題点を解決することができれば,実験方法は，水槽に砂を安息角に揃えて考案した新型モデルの人工リーフの実用化

設置し，次に一定の量の水を入れ，LEGO

により近づき,海岸侵食の問題に対して効

Mindstorms を用いて造波装置から波を発果的な対策ができると見込まれる。

生させ，侵食の様子を 35 秒間撮影した。
その工程をそれぞれ 6 回行い，0 秒の時点と 35 秒の時点の静止画を ImageJ というソ
フトウェアを用いて解析し，浸食面積を測定した。

図 1．旧型モデルの人工リーフ

図 3．旧型人工リーフ 水草付き

2－2．波のエネルギーの減衰率
この実験は，立命館大学理工学部の実験施設を使用させていただき，施設内の規則
図 2．新型モデルの人工リーフ

波を発生できる造波装置を使用して波高を測定した。水の密度と重力加速度を定数と2．方法

みなすと，図 4 を参考に，波の単位面積あ2－1．水草の着生による侵食への影響

たりのエネルギーは波高の 2 乗に比例する

3D プリンターで作成した旧型と新型の人工リーフに，それぞれ等間隔に 108 個の穴を開け，図 3 に示すようにその穴にスズ
ランテープで作成した水草のモデルを取り付け，水草を着生させた場合と見立てて，波による浸食面積の測定実験を行った。
水草の有無だけでなく，個数による違いも比較したかったため，私たちは水草のモ
デルを 108 個(100%)，54 個(50%)，0 個(0%)の 3 パターンに分けて取り付け，そことがわかる。
この式を用いて,人工リーフを通過する前の波のエネルギーが通過後に何％減少する
かを求め，これを減衰率と定義してデータを比較した。
この実験では，３D プリンターでの新型
人工リーフのモデル作成が困難であったため，コンクリート製のものを使用した。この人工リーフモデルは土台部分と突起部分に分けて自作し，突起部分については，クリア- 130 -

ファイルを漏斗型に成形して型を用意し，新型人工リーフの突起物の個数・配置をその型にコンクリートを流し込んで作成し以下の４パターンに設定し，造波装置からた。

波高 2.0 cm, 3.0 cm, 4.0 cm の波を発生させ，人工リーフ通過前と通過後の波高を測定した。
突起物のパターンは個数 176 個(100％)，
個数 104 個(59％)のジグザグ配列と縦配列，そして個数 88 個(50％)のジグザグ配列の計 4 パターンである。

図 4．単位面積あたりのエネルギーの公式

3．結果と考察3－1．水草の着生による侵食への影響
人工リーフに着生した水草の被度割合が大きいほど侵食面積が小さくなっていることがわかった。また，6 回の実験による浸食面積の平均値をグラフ化し，T 検定を用いて比較したところ，新型モデルの場合
は，水草 100％と水草 50％・水草 100％と図 5．コンクリート製新型人工リーフ
2－2－1．天端水深による波高の変化と減衰率の算出
図 6 に示す水深を天端水深と定義し,これを 1.0cm, 2.0 cm,あることがわかった。
人工リーフに着生した水草の被度割合が大きいほど浸食面積が小さくなっていること言えるだろう。水草を単体で見たときのから波高 2.0 cm, 3.0
天端水深

生させ，人工リーフ

メリットとして水質がきれいになったり,
魚の新たな住みかになったりもすることがあるので水草が着生することでそのような通過前と通過後の波効果をあるかもしれないと考察することが図 6．天端水深2－2－2．突起物の個数と配置による波高の変化と減衰率の算出

草 100％と水草 0％を比較したときに差がーフの本来の効果が損なわれることはないに設定し，造波装置

高を測定した。

ことがわかった。旧型モデルの場合は，水とから,水草が着生することで新型人工リ

3.0 cm, 5.0 cm, 7.0 cm

cm, 4.0 cm の波を発

水草 0％を比較したときに大きく差があるできる。
3－2．天端水深と減衰率の関係
天端水深を変化させた結果，表 1 のようになった。赤色が減衰，青色が増幅を表し- 131 -

ている。この表から新型人工リーフは波高に入れてさらに実用化に向けての案をだすと干渉する水深のときに最も減衰率への影ことができると考えた。

響があることがわかった。しかし，波高に

表 2．突起物の個数と配置の変化による減衰率

干渉しない一定の範囲においては逆にエネ
ルギーが増えていることがわかった。
エネルギーが増えてしまった原因として,人工リーフの形と天端水深と波の波高の関係性が大切なのではないかと考えることができる。とくに,形状については台形の形のため波が人工リーフに干渉した際に波のエネルギーを波の進行方向の反対がわではなく,上側に一部逃げてしまっている

4．展望
人工リーフへの水草の着生によって人工のではないかと考察をした。

リーフのエネルギーの減衰に影響がないこ

表 1．天端水深の変化による減衰率とがわかった。しかし,人工リーフの素材であるコンクリート上で水草が生育可能か確認できていない。そのため,できる限り
実際の環境を再現したうえでコンクリートに水草を植えて育つが確認する必要がある。また,今回波のエネルギーを求める公3－3．突起物の個数と配置と減衰率の関係
新型人工リーフの突起物の個数と配置を変えて実験を行った結果，配置による大きな変化は見られず，基本的に突起物の個数によって減衰率が大きく変化することがわかった。しかし，突起物の個数が 176 個

式的に習慣的な波のエネルギーを求めて比較したため,次は継続的な波のエネルギーを求める公式を使ってそれを求めて比較を行ってみたい。また,津波が発生する地域に置くことも考慮して津波に対しての効果があるのかないのか,ある場合どれくらいあるのかを調べたい。最後に,新型人工リ(100％)のときと 104 個(59％)を比較した
ときに，個数に大きな差があるにも関わらず，いずれも減衰率が最大 7 割近くで止まっていることがわかった。

ーフによる減衰率の上限が 7 割あるということを利用して,最適な配置と個数を見つけてなおかつ水草の生育条件や建設コストなどの実用化の際のことも考慮したうえで最大の減衰率が 7 割であるとしたら,水草が十分育つことのできる面積を確保したう
えで突起物の個数を減らした形状があるかもしれない,もしある場合突起物 100％の時よりも建設コストなども減らすことを視野最も効果的である人工リーフの形状を考案
し,実際の海に置いて実験を行ってみたいと考えている。
5．謝辞- 132 -

本研究の遂行に多大なるご協力してくだ

素・窒素およびリン量の見積もりさった[Estimation of carbon, nitrogen, and立命館大学工学部 藤本将光教授

phosphorus content of swordfish beds

徳島大学 環境防災研究センター 客員教

formed on artificial reefs].

授 近畿大学 農学部水産学科 講師

https://doi.org/10.18903/pamjsfe.2003.0_2

中西敬教授

1

和歌山工業高等専門学校生物応用科学科

齋藤 正文 [Saito, M.] (2001) 多様な生物

楠部真崇教授環境を創造する新型人工リーフの安定性お

立命館高校 辻本遼二郎先生には，この場をかりて厚く御礼申し上げま

よび水産効果に関する研究 [Research onす。

the stability and fisheries effects of a new

6．引用文献diverse biological environment]. 海岸工

type of artificial reef that creates a
学論文集, 第 48 巻, 土木学会 [Journal of

Artificial Reef. (2022). Electric Power

Coastal Engineering, Vol. 48,

Civil Engineering

JSCE]. https://doi.org/10.2208/proce1989.

Association. https://www.jepoc.or.jp/

48.946

Basic Earth Science.
(2022). Shinkoshuppansha Keirinkan

水産庁 [Fisheries Agency]. (n.d.) 藻場

Coastal erosion. (2022). Nationalの働きと現状 [Function and current

Institute for Land and InfrastructureManagement. http://www.nilim.go.jp/lab/
fcg/labo/01_01.html

status of seaweed beds].
https://www.jfa.maff.go.jp/j/kikaku/tamenteki/kaisetu/moba/moba_genjou/

Coastal Features. (2020). Japan
Ministry of Land, Infrastructure,

轟 元気 [Todoroki, G.] (2021)

Transport and Tourism.
https://www.mlit.go.jp/river/kaigan/main/
kaigandukuri/sugata01.

【IAPLC2021 出品】コンクリ水槽の作り
方 [How to make a concrete water tank].
https://ordinaryaquarium.design/contest/iaplc2021

Minami Kujukuri Beach Nourishment
Plan. (2015). Chiba
Prefecture. https://www.pref.chiba.lg.jp/kasei/keikaku/minamikujyuukuri/docume
nts/keikaku2.pdf
木下 淳司 [Kinosita, J.] et al. (2003).
人工リーフに形成されたカジメ藻場の炭第 7 章波力発電 7.1 波のエネルギーとパワー [Chapter 7 Wave Power
Generation 7.1 Wave Energy and Power].
(2022, October 27). TriEN+.
https://trienplus.com/wave-energy-andpower/- 133 -

The Effect of Auditory Stimulus on the Olfactory Sensory Artificial Reef with Effective
Shape and Protection of Marine Ecosystems

G12 SSG Course
Ritsumeikan High School
JSSF 2023
January 19, 2024

Abstract
Last year's experiments suggested that the new type of artificial reef that was devised was more effective thanthe old type. However, since problems for practical application remained, it was decided to conduct the study
considering the marine ecosystem, production cost, etc. 108 holes were drilled in a plastic artificial reef createdby a 3D printer and attached water plant models created with lily tape in three patterns: 100%, 50%, and 0% of
the number of holes. The model water plants were attached to the reef in three patterns: 100%, 50%, and 0% of
the holes. Six patterns of the old and new models were made and submerged in a 90 cm tank, and the area ofsand erosion by waves was measured. The results showed that the larger the surface area of the water plants, themore the erosion area was affected. Next, we measured the increase or decrease in energy from waveforms
before and after waves passed through the concrete artificial reef by varying the top water depth, wave height,
number of protrusions, and wave height. When top water depth and wave height were varied, wave waveform
interference with the artificial reef was greatly reduced, but energy amplification was observed at some wave
heights. When the number and placement of protrusions and wave height were varied, the effect depended on
the number of protrusions, and the upper limit of attenuation was found to be about 70% under all conditions. It
is necessary to devise a way to create depressions in the protrusions to release the energy. Finally, water plants
were found to be effective in attenuating waves, but it is necessary to confirm whether they can grow on concrete,
the material of the artificial reef. Also, since we measured the instantaneous energy in this study, we need tomeasure the continuous wave energy.
Keywords: artificial reef, marine ecosystem, water plants, erosion area, wave height- 134 -

I. Introduction
In the past 15 years, sandy beaches in the Japanese archipelago have lost about 13% of
their area to coastal erosion. The government has been promoting the construction of
breakwaters as a countermeasure. There are several types of breakwaters, including detachedbreakwaters higher than the water surface, tetrapods, and artificial reefs. An artificial reef is a
structure built under the water's surface that mimics the wave-canceling function of a coral reef
and is expected to reduce coastal erosion. The advantages of artificial reefs over otherbreakwaters are clear. However, when we looked up articles on artificial reefs, we found that
there were few descriptions of the shape of artificial reefs, only those related to the depth anddistance of the top edge. Therefore, we began research on artificial reefs to devise a new shape.
In the previous year's research, we had studied the general shape of the previous model.
The new model was designed to mimic the shape of sound-absorbing material, and the results
suggested that the new model was more effective. However, installing an artificial reef itself
harms the marine ecosystem, and the manufacturing cost is high. If these problems can besolved, the new model of artificial reefs will be closer to practical application and will be a more
effective solution to the problem of beach erosion.

Fig.1 Model of conventional type of artificial reef

Fig.2 Model of new type of artificial reef

- 135 -

II. Materials and Method
2.1 Influence of Water Plant Attachment on Erosion
We measured the area of erosion caused by waves by making 108 holes at equal intervals
in the old and new types of artificial reefs made by a 3D printer and attaching a model of water
plants made by tinned tape to each hole, as if the reefs were covered with water plants.
Because we wanted to compare the difference not only by the presence of water plants but
also by the number of water plants, we installed 108 (100%), 54 (50%), and 0 (0%) water plants
models in three different patterns, and conducted the experiment using both the old and newmodels, thus measuring the erosion area of sand in a total of six artificial reef patterns andcomparing their effects. The experimental method was to place sand in an aquarium tank.

Fig.3 New type artificial reef with water plants models attached

2.2 Attenuation Rate of Wave Energy
For this experiment, we were allowed to use the experimental facilities of the Faculty of
Science and Engineering, Ritsumeikan University, and measured wave heights using a wave
generator that can generate regular waves in the facility. If the density of water and theacceleration of gravity are regarded as constants, the energy per unit area of the wave is
proportional to the square of the wave height.

- 136 -

Using this equation, we determined what percentage the energy of the wave before passing
through the artificial reef decreased after passing through, which we defined as the attenuation
rate, and compared the data.
In this experiment, a concrete model of the new artificial reef was used because it wasdifficult to create a model of the new artificial reef using a 3D printer. The model of the artificial
reef was made by dividing it into a base part and a projection part. For the projection part, a mold
was prepared by molding a clear file into a funnel shape, and concrete was poured into the mold.

Fig.4 Formula for finding the energy of a wave

Fig.5 Overall view of artificial reef

2.2.1 Variation of Wave Height and Attenuation Rate with Depth of Water at Top Edge
The distance between the top of the artificial reef and the bottom of the water surface isdefined as the top water depth, which is defined as 1.0 cm, 2.0 cm, and waves with heights of 2.0
cm, 3.0 cm, and 4.0 cm were generated by the wave generator, and the wave heights before andafter passing through the artificial reef were measured.

- 137 -

2.2.2 Calculation of Wave Height Variation and Attenuation Rate by the Number andArrangement of Protrusions
Waves of 2.0 cm, 3.0 cm, and 4.0 cm in height weregenerated by the wave generator, and the wave heights before
and after passing through the artificial reef were measured.
The patterns of protrusions were 176 in number (100%),
104 in number (59%) in zigzag and vertical arrangement, and
88 in number (50%) in zigzag arrangement, for a total of 4
patterns.
Fig.6 Topwater depth

III. Data Analysis
3.1 Effect of Water Plant Cover on Erosion
It was found that the larger the percentage cover of water plants attached to the artificial
reef, the smaller the erosion area. The mean erosion area from six experiments was graphed andcompared using the T-test, and it was found that in the case of the new model, there was a large
difference when comparing 100% water plants to 50% water plants and 100% water plants to 0%
water plants. In the case of the old model, it was found that there was a difference when 100%water plants and 0% water plants were compared.
3.2 Relationship Between Topwater Depth and Attenuation Rate
Table 1 shows the results of varying the top water depth. Red indicates attenuation, andblue indicates amplification. This table shows that the new artificial reef has the greatest effecton the attenuation rate at depths that interfere with wave height. However, it was found that the- 138 -

energy of the new artificial reef increased within a certain range where it did not interfere withwave height.
As the cause of the energy increase, we can consider that the relationship between the
shape of the artificial reef, the top water depth, and the wave height may be important. In
particular, the trapezoidal shape of the artificial reef may have allowed some of the wave energy
to escape to the upper side of the reef when waves interfered with it, rather than to the opposite
side of the direction of wave travel.
Table.1 Function of topwater depth

3.3 Relationship between the Number and Arrangement of Protrusions and Attenuation Rate
Experiments were conducted by changing the number and arrangement of protrusions on
the new artificial reef. The results showed no significant change depending on the arrangement;
basically, the attenuation rate changed significantly depending on the number of protrusions.
However, when the number of protrusions was 176 (100%) and 104 (59%), it was found that theattenuation rate stopped at a maximum of nearly 70% in both cases, despite the large differencein the number of protrusions.
If the maximum attenuation rate is 70%, we thought that there might be a shape in which
the number of protrusions is reduced after securing an area in which water plants can growsufficiently. If so, construction costs and other costs might be reduced compared to when thenumber of protrusions is 100%.

- 139 -

Table.2 Change in placement

IV. Discussion
Since the erosion area decreases with the percentage cover of water plants attached to theartificial reef, it can be said that the attachment does not impair the effect of the new type of
artificial reef. The fact that the wave energy increases within a certain range without interferingwith wave height suggests that the shape of the new artificial reef is not effective under all
conditions but that the direction of the wave force may be lifted upward. The energy may be
amplified depending on the depth at the top edge of the reef. Furthermore, the fact that theattenuation rate of the new artificial reef is only about 70% despite the large difference in thenumber and arrangement of the protrusions suggests that the upper limit of the attenuation rateby the new artificial reef may be about 70% and that the most effective arrangement of the
protrusions may exist.
V. Conclusion
Although it was found that the growth of water plants on the artificial reef is effective inattenuating wave energy, it has not been confirmed whether water plants can grow on concrete,
the material used for the artificial reef. Therefore, it is necessary to try growing water plants on
concrete in an aquarium with frequent water changes, assuming the actual circulation of ocean
currents, given the hard and alkaline nature of concrete water. In addition, since we obtained- 140 -

instantaneous wave energy this time, we would like to measure the period to obtain thecontinuous wave energy next time. Then, considering the possibility that the upper limit of theattenuation rate by the new artificial reef is about 70%, we would like to experiment to find the
optimal arrangement and number of reefs.
VI. Future Research
Although it has been found that the energy attenuation of the artificial reef is not affectedby the attachment of water plants to the artificial reef, it has not been confirmed whether water
plants can grow on concrete, which is the material of the artificial reef. Therefore, it is necessary
to confirm whether water weeds can grow on concrete by planting them in the actual
environment as much as possible. In addition, since we compared the energy of habitual waves
using the formula for determining the energy of waves this time, we would like to use theformula for determining the energy of continuous waves next time and compare the results. In
addition, we would like to investigate whether or not the reef is effective against tsunamis, and if
so, how much effect it has, taking into consideration the fact that it is placed in an area wheretsunamis occur. Finally, we would like to find the optimal arrangement and number of artificial
reefs, taking into account the conditions for growing water plants and the cost of construction,and devise the most effective shape of artificial reefs, and conduct experiments by placing themin the actual sea.
VII. Acknowledgements
We wish to thank Leave a Nest for their generous financial assistance. Also, thankProfessor Masataka Kusube of Wakayama National College of Technology, Professor
Masamitsu Fujimoto of Ritsumeikan University, and Professor Takashi Nakayama of Kinki
University for their helpful discussions and advice.

- 141 -

VIII. References
Artificial Reef. (2022). Electric Power Civil Engineering Association. https://www.jepoc.or.jp/
Basic Earth Science. (2022). Shinkoshuppansha Keirinkan co.,LTD
第 7 章波力発電 7.1 波のエネルギーとパワー [Chapter 7 Wave Power Generation 7.1 Wave
Energy and Power]. (2022, October 27). TriEN+. https://trienplus.com/wave-energy-andpower/
Coastal erosion. (2022). National Institute for Land and Infrastructure Management.
http://www.nilim.go.jp/lab/fcg/labo/01_01.html
Coastal Features. (2020). Japan Ministry of Land, Infrastructure, Transport and Tourism.
https://www.mlit.go.jp/river/kaigan/main/kaigandukuri/sugata01.
水産庁 [Fisheries Agency]. (n.d.) 藻場の働きと現状 [Function and current status of seaweedbeds]. https://www.jfa.maff.go.jp/j/kikaku/tamenteki/kaisetu/moba/moba_genjou/木下 淳
司 [Kinosita, J.] et al. (2003). 人工リーフに形成されたカジメ藻場の炭素・窒素およびリン量の見積もり [Estimation of carbon, nitrogen, and phosphorus content ofswordfish beds formed on artificial reefs]. https://doi.org/10.18903/pamjsfe.2003.0_21
Minami Kujukuri Beach Nourishment Plan. (2015). Chiba Prefecture.
https://www.pref.chiba.lg.jp/kasei/keikaku/minamikujyuukuri/documents/keikaku2.pdf
齋藤 正文 [Saito, M.] (2001) 多様な生物環境を創造する新型人工リーフの安定性および水産効果に関する研究 [Research on the stability and fisheries effects of a new type of
artificial reef that creates a diverse biological environment]. 海岸工学論文集, 第 48 巻, 土
木学会 [Journal of Coastal Engineering, Vol. 48, JSCE].
https://doi.org/10.2208/proce1989.48.946
轟 元気 [Todoroki, G.] (2021)【IAPLC2021 出品】コンクリ水槽の作り方 [How to make aconcrete water tank]. https://ordinary-aquarium.design/contest/iaplc2021- 142 -

Artificial reef with effective shapeand protection of marine ecosystems

Ritsumeikan High School

Abstract
We are investigating artificial reefs that can effectively shape and protect marine ecosystems. An artificial reef is a type of breakwater; a measure designed to control
coastal erosion. Breakwaters that are constructed under the surface of the water and have the effect of dissipating waves are called artificial reefs. Prior researchsuggested that artificial reefs with new shapes were effective in controlling beach erosion. Our current efforts are concentrated on two aspects. Firstly, creating newunderwater habitats for organisms by growing waterweeds on artificial reefs, studying the influence of the presence of waterweeds on wave dissipation and reducing
the burden on the marine ecosystem from the installation of artificial reefs. Secondly, dividing the wave amplitude into stages using a wave generator device,
and examining the rate of reduction in wave energy passing over the artificial reef. The performance of the invented artificial reef will be evaluated by comparing thedifference between the invented artificial reef and a conventional artificial reef to confirm whether the effect is superior in all locations, including areas where highwaves caused by typhoons are less likely to occur and areas where waves are calm. The final goal is to optimize the newly designed artificial reef for various coasts.

Introduction

Experiment 2

In the last 15 years, Japan's sandy beaches have lost about 13% of their total
area to coastal erosion. The government has been promoting the constructionof breakwaters as a countermeasure. We are conducting research on artificial
reefs, which are structures built under the surface of the water that mimic thefunction of coral reefs to dissipate waves.

Aim

Pre-Experiment

Materials

In a pre-experiment, the performance of an older artificial reef with a common
shape and a new type artificial reef that mimics the shape of sound-absorbing
material were compared looking at how much each controlled beach erosion.
Sand

Fig. 1 Model of the conventional typeFig. 2 Model of the new typeFig. 3 Experimental conditions

Artificial reef

Method
1. Sand was placed in the tank‘s angle of repose.
2. Water was put into the water tank.
3. A wave-making machine made from LEGO
Mindstroms, was placed above the water tank.
4. 35 seconds of video was taken.
5. The area was measured using ImageJ.
6. Steps 1~5 were repeated 6 times.

LEGO
Mindstorms

To compare the change in wave height whenchanges are made to the:(1) depth of the water above the artificial reef(2) number and placement of protrusions
water, wave tank, concrete artificial reef, brickMethod
1. The concrete artificial reef was placed in the tank
2. Wave heights were adjusted to 2 cm, 3 cm, and 4 cm before passing
through the artificial reef.
3. The heights of the waves were measured after they passed through theartificial reef.
Experiment 2-1• Steps 1 to 3 were performed as above, setting the depth at the top of thereef to 7 cm, 5 cm, 3 cm, 2 cm, and 1 cm.
Experiment 2-2• Steps 1 to 3 were performed as above with 4 different patterns of thenumber and arrangement of protrusions on the artificial reef.
The comparison method applies this formula for energy per unit area.

FIg. 4 Result of erosion area

Results suggest that the new type artificial reef was the most effective.

Result𝐸=

Crest water depth
（cm）

5.0

2.0

9.8%

0%

Experiment 1

3.0

0%

Aim

4.0

New type > conventional type > none1
𝜌𝑔𝐻2 [J/m2 ]8

Wave height
（cm）

3.0

ρ[kg/m3 ] ∶ water density
𝑔 [m/s2 ] ∶ gravitational acceleration
𝐻 [ m ] : wave height

Table 2 Attenuation rate with change in number and arrangement

Table 1 Attenuation rate with change in top water depth

7.0

2.0

－44% －56%

1.0

Number andarrangement

176(100%) 104(59%) 104(59%) 88(50%)
ZigzagVertical line

Zigzag

2.0

44%

－10%

0%

－21%

3.0

56%

41%

36%

19%

4.0

70%

72%

67%

58%

Wave height
（cm）

44%

ZigzagTo study the change in the effect on shoreline erosion when models of water
plants are attached to an artificial reef.

Materials
water, water tank (900 mm×250 mm×300 mm), LEGO Mindstorms, Sand,
Model of water plants

Fig. 5 A conventional type (with water plant models）

Fig. 9 Concrete artificial reef

Fig. 6 A new type (with water plant models）

Fig. 7 Experimental conditions (with water plant models）

Method108 holes were drilled in each of the two artificial reefs. Holes were 2 cm apart.
Three tests were conducted with the new type and convention type artificial reefmodels. In the first test, water plant models were placed in 100% of the holes(108 holes). In the second test, water plant models were placed evenly in 50% of
the holes (54 holes). And in the last test, no plant models were placed. The
results were measured in the same way as in the pre-experiment.

Result
The results showed that the greater
the number of water plants
attached to the artificial reef, thesmaller the eroded area. Attachingwater plants was not found to effectof the efficiency of the new type of
artificial reef.

－21% －78%

0%56%－5.1% －27% －10%

64%

70%

Vertical line

Experiment 2-1
Attenuation rates increased when the artificial reef interfered with wave heights.
In addition, wave energy was amplified under certain conditions.
𝐸´(1－ ) × 100= 𝜀 ε[%] : attenuation rate
𝐸₀
Experiment 2-2
The attenuation rate was highly dependent on the number of protrusions. If thenumber of protrusions is the same, there is no change due to the different
placement of the protrusions. Furthermore, the attenuation rate of the newmodel's artificial reef may be limited to 70%.

Conclusions / Future Plan
Future experiments will first verify whether water
plants can grow on concrete in this experiment. In
addition, future experiments will elucidate why theenergy of waves passing through the artificial reef
increase in certain case due to changes in top and water
depth. Then, the number and placement of the mostsuitable number of pieces for cost reduction will beverified.

Fig.10 Concrete with water plants attached

References

Fig. 8 Result of erosion area（with water plants models）

Acknowledgements
We wish to thank Leave a Nest for their generous financial assistance. Also,
Professor Masataka Kusube of Wakayama National College of Technology,
Professor Masamitsu Fujimoto of Ritsumeikan University, and Professor
Takashi Nakayama of Kinki University for helpful discussions and advice.

1. Artificial Reef. (2022). Electric Power Civil Engineering Association. https://www.jepoc.or.jp/
2. Basic Earth Science. (2022). Shinkoshuppansha Keirinkan co.,LTD
3. Coastal erosion. (2022). National Institute for Land and Infrastructure Management. http://www.nilim.go.jp/lab/fcg/labo/01_01.html
4. Coastal Features. (2020). Japan Ministry of Land, Infrastructure, Transport and Tourism.
https://www.mlit.go.jp/river/kaigan/main/kaigandukuri/sugata01.
5. Minami Kujukuri Beach Nourishment Plan. (2015). Chiba
Prefecture. https://www.pref.chiba.lg.jp/kasei/keikaku/minamikujyuukuri/documents/keikaku2.pdf
6. 木下 淳司 [Kinosita, J.] et al. (2003). 人工リーフに形成されたカジメ藻場の炭素・窒素およびリン量の見積もり [Estimation of carbon,
nitrogen, and phosphorus content of swordfish beds formed on artificial reefs]. https://doi.org/10.18903/pamjsfe.2003.0_21
7. 齋藤 正文 [Saito, M.] (2001) 多様な生物環境を創造する新型人工リーフの安定性および水産効果に関する研究 [Research on the stability
and fisheries effects of a new type of artificial reef that creates a diverse biological environment]. 海岸工学論文集, 第48巻, 土木学会 [Journalof Coastal Engineering, Vol. 48, JSCE]. https://doi.org/10.2208/proce1989.48.946
8. 水産庁 [Fisheries Agency]. (n.d.) 藻場の働きと現状 [Function and current status of seaweed beds].
https://www.jfa.maff.go.jp/j/kikaku/tamenteki/kaisetu/moba/moba_genjou/
9. 轟 元気 [Todoroki, G.] (2021)【IAPLC2021出品】コンクリ水槽の作り方 [How to make a concrete water tank].
https://ordinary-aquarium.design/contest/iaplc2021
10. 第7章波力発電 7.1 波のエネルギーとパワー [Chapter 7 Wave Power Generation 7.1 Wave Energy and Power]. (2022, October 27). TriEN+.
https://trienplus.com/wave-energy-and-power/