Physics Education for Young
GenerationKiichiro Kagawa
NPO: Fukui Science Education AcademyJAPANThe Aim of our NPO (FSEA)• 1) Science workshop for young people• 2) Development of new experiment• 3) Cooperation with foreign countries
Retired from Fukui Univ. in 2010, while NPO wasfounded in 2009

Regular private class for children (2009~2014),
two times in a month, Sat. ９：３０～１２：００
大気圧の実験（留学生が指導）

児童が自分の考えを述べている
CD分光器をつくっているところ

水を入れるとコインが浮かび上がってくる（竹ぐしは目の位置の基準にする）

Our hope is to bring up excellent scientists and engineers

The most representative educational experiment
we developed
Frictionless equip.

Artificial snow crystal

PATENT:No. 5257879
All these were published
In J. Phys. Education (England)

Water lens microscopeAttitude towards Physics Education（１）Try to Separate from school textbooks（２）Try to use ordinary materials. Don’t use
commercial kits, which degrade children’s ability.

（３）Try to encourage to have logical thinking
through experiments（４）Try to use beautiful phenomena as the topics
of study (rainbow, snow crystal so on)（５）Try to encourage to repeat the experiment withcareful observation (small discovery)
Even physics education, there should be originality.

Chapter １• Frictionless Demonstration Using Fine
Plastic Beads
for Teaching
Mechanics
FrictionlessDemonstration
Using
Fine Plastic
Spherical Beads for Teaching Mechanics

Introduction• Mechanics is most important to understand Physics system• However, only through training to solve calculation problem in highschool

Most unpopular subject in high school

The reason
1) Due to the friction, we cannot demonstrate
the law itself.
2) For falling objects, phenomena finish
in a short time (less than 0.5 second).
Student cannot see carefully with enoughunderstanding

Commercial equipments forfrictionless motion

Car (1set): ¥21.000

Car including slope ¥46.000

Air slide track ¥210.000 (2000 US$)

Diameter isabout ０．３ｍｍ

Microscopic viewof Plastic beads
1㎜Work as ball bearing; beads are rotating

Plastic beads

Uniform linear motion

Almost no energy loss because themass is very small

Demonstration of the principle of thisfrictionless equipment for children

The plate with doll move smoothly,
The Ping-Pong balls are rotating.

Rainbow ExperimentUsing Fine Plastic Beads

Beads scattered on a black paper work, same as water droplet.

How to treat the beads

Take out the breads after
experiment using vacuum cleaner,or wipe with wet paper

Scatter like shaking pepper .
Almost invisible for our eye.
But if you look at the surface froman oblique, it looks slightly white.

iron ball bearing

Book ofNuffield “O”
level(1972),
using metal
smallball(1~2mm)
Heavy object: ~1kg
Only horizontal surface,
No application for slope

Published in Journal of Physics Education2008Ａｄｖａｎｔａｇｅｓ ｏｆ Ｂｅａｄｓ Method
・Easily obtainable object of which bottom is flat(but should be light)
・Very cheap( 80 US$ for 1 bottle (700g),
one time only a few g)
・Even slope, the beads can be attached byelectrostatic force. (frictionless slope)・Systematic understanding is made because all
experiments are done using the same object on thefrictionless plate.
.Students can touch the equipment by themselves
as they like.
Weak points: 1) In high humidity, friction increases
2) Too much density increases friction

Objects used for frictionless demonstration
petridishlid
Bottom plane should be flat and less 100g

Equipments for frictionless demonstration
Size: 183 x 91 x 6 cm
Weight: 7.5 kg(Using Styrofoam,but covered by 2mm
Plastic plate)

Flatness is important

90 x 60 x2 cm, 7kg
For group experiment(ordered to professional)
We say, “friction plate”, “ beads plate”

First Law of motion(Uniform linear motion,viewed from the top)

Strobe lighting; T=0.25s

Pulse light source to record the track
Diode light source(red or green); Off and on , Periodically flash

Petri dishRepetition :5 Hz

Recorded using a digital camera: 1sec

Circular Motion Using a String andCylindrical pipe
Projected shadow

Bright light source

Plastic
lid with aholepinstring

Using projected shadow,
We can show that circularmotion is Simple harmonic
oscillation

If there is quite no friction, thecircular motion keeps going onlike a planet motion.

Rotation of rigid bodyCenter of mass
Center of mass

On the frictionless plate

Usually, to have the image is difficult
for students

Law of conservation ofangular momentum( L = r x p )Circular motion using string

End of string was fixed so as to be coiled aroundthe pole; ( with decreasing r , V increase )Law of inertia
Suspended weight

Uniform motion

Weight moves to frontward

It stay there;

Pull suddenly

no transmission of force

F=ma(運動の第二法則)
High school textbook

Using Wheel car
For students, it is difficult tounderstand that this is a general low

Demonstration of second law

M

Accelerated motion

LED, 10 Hz

On bead plate
pulsarConstant force
Petri dish

Weight:２０ｇ

Ｍ＝53.４ｇ

V = △X/ △T

Ｍ＝153.４ｇ

MAcceleration

F=ma(Second Law of Motion)
We can change m and F,
independently.

ビーズ板
Constant force

F: weight(２０ｇ)
Ｆ＝ｍａ

Under various mass250(48.8g)

The relationshipbetween time andvelocity

平均の速度ｖ [ｃｍ/ｓ]

200150(98.8g)

100(148.8g)
50(248.8g)

00

0.1

0.2

0.3

0.4
時間ｔ [秒]

0.5

0.6

0.7

0.8

Action and Reaction Law(Third law of motion)
Repulsion force each other,
without touching
S N
S N

N S N S

N S

S N

S N

High school textbook

On the frictionless table

Circular magnet
Small Neodymium
magnet are arranged
In a circular form図8-2

Demonstration
using circular magnet,
under strobe flash light

改良型
小型ネオジム磁石

Action and reaction, using jumping frog

Usually, difficult to see the force itself

Demonstration on practice problem
On the smooth surface C, there is an object D (M kg) on the smooth slope
B, of which angle is Θ. Another 0bject A (m kg) is placed on the slope
quietly. Then, the object C slide down on the slope because of no friction
between the surfaces.
Questions:
1) What is the acceleration of A against C ( in X, Y component)
2) What is the relative acceleration of A against D3) What is the relative acceleration of D against C

We can demonstrateusing the frictionlessplate and frictionlessslope.

Free falling object

Falling object on a slope
Frictionless slope

Ｍｇ

Mgsinθ
Mg cosθ
Mｇ

Ｆ＝Ｍｇ
a=ｇ

Ｆ＝Ｍｇsinθ

a=ｇsinθ(small)Acceleration become small by using slope,
when Θ＝１°acceleration =(１/６０)g
We can see the phenomena as slow motion, easy to understand.

Can measure the force tothe slope direction

Inclining frictionless table

Smooth slope

Free-fall on the smooth slope

Regardless of the mass,
falling is the same
We can see in slow motion

The relation of distance and time
1.20
1.00
Distance(m)Angle of slope ：0.8
time：~3.5 sec
acceleration：0.13m/s2Time vs. length

0.80
0.60
0.40
0.20
0.00
0.00

1.00

2.00

3.00

4.00

Time(s)Timevs. velocity
The relation of velocity and time
0.6
0.5
Velocity（m/s）

Uniform acceleration
motion on theinclined beads plate

0.4
0.3
0.2
0.1
0.0
0.0

1.0

2.0

3.0

4.0

Time（ｓ）

Measurement can be madeusing a stopwatch(very instructive)

Monkey Hunting
Vertical direction motion is thesame between the monkey andthe stone

ｘ方向と、ｙ方向の運動は独立。
サルも弾もｙ方向に対しては同じ落下運動をする。

Commercial equip.
¥39,000

Experiment of monkey hunting
using the inclined beads plate
One --Two--Startmonkey

Regardless of the speed
The stone can attack
The monkey

Both Monkey and stone,
the motion of
the Y direction is the same .
The Motion takes place slowly

ⅹstoney10

Stone is shot aiming the monkey

What angle gives the mostfar distance? (under the same initial speed)x  v0 cos  t
1 2gt`  v0 sin   t (ｇ`＝ｇsinθ)2gx`y  x tan   22
2v0 cos  tan   2v02 cosx  0, x gy

ⅹyv02 sin 2
gxmax  sin 2  1

  450

Many Application ofFrictionless Plate

Horizontal spring vibration

Model for diatomic molecule

Concept of 3 kinds motion: Vibrational, Rotational, Translational

Non-gravity (Weightlessness) demo.
beads

beads
In a elevator, whichfreely fall.

During the falling on the frictionlessslope(~20o) , no expansion of the springCollision

Completely exchange

Small one is repelledMomentum conservation forinclined collision○×○×
Before collision

After collision

Composed momentum vector is conserved

Conversion from potential energy to kinetic
energy （beads are attached by electrostatics force ）11mvo2  mgho  mv 2
221mgh1  0  0  mv 221mv 2  mgh1
2mgh1 

Plastic sheet with fine beads

Speed meterｈv
Beads platev
エネルギーの変換

エネルギー変換

Velocity vs. height
3.51093y = 19.605x
y = 18.774x8theory
2.5

7ｖ２[ｍ/ｓ]２ｖ[ｍ/ｓ]

2 gh1

2

measurement

1.5

654
312

0.5

1000

0.05

0.1

0.15

0.2

0.25
ｈ[ｍ]

0.3

0.35

0.4

0.45

0.5

00.05

0.1

0.15

0.2

0.25
ｈ[ｍ]

0.3

0.35

0.4

0.45

0.5

Comparison of falling speed between balland petri dishSmooth slope
Plastic sheet

ball

Petri dishBall is late:(energy is consumed forrotating the ball, thus kinetic
energy of motion is reduced )Elastic and Inelastic collision
CushionBound slowly （no movement of small plastic balls）

Stop
Energy change tothermal energy

Collide with hard wall, plastic balls move randomly

High sensitive detection of magnetic force
Beans plate

The bar magnet direct to North

Application of Frictionless Plate
For Wave Demonstration
Wave propagate very fast, thus it is very
difficult to observe。
We made slowly propagating waves using thefrictionless table.

Slowly-moving wave
Plastic lid (diameter 5cm) is connected using a thinrubber string for wave propagation.
Frictionless Plate
Fine beads

Chain of thin plastic lid.

Reflection of wave at fixed edge

Reflection of wave at free edge

Standing wave

Superimpose of Waves(+ ,+ )Textbook

Wave machineSuperimpose of Waves(+,+)

Superimpose of Waves(+,-)

International seminar in Fukui

10 students (Syiah Kuala Univ. ,Faculty of Science)came to Fukui to attend internationalseminar under the support ofJapan Monbushou (2008).

Questionnaire survey from university students
Before demonstration

After demonstration

Inertial law
慣性の法則

Inertial law
慣性の法則

A little
understand

46Understand

10F=ma1397Action and reaction
作用・反作用の法則

Action and reaction
作用・反作用の法則

1

don’t
understand4

F=ma510

Chapter 2 Using Fine• Frictionless Demonstration
Short
Presentation
Using
Movie
PlasticBeads
for Teaching
Mechanics
1) Frictionless exp.
2) Soap bubbles exp.
3) Air gun exp.
(workshop for children including
mentally disable children)
From a small workshop in Fukui (Aug. 8, 2017)

END
Thank you very muchfor your attention