Newsgroup: it.scienza.astronomia
Titolo: Per gl'Insegnanti_03

2.3 Teaching and Learning the Phases of the Moon: Middle and High
School
Dove (2002) used a small and homogeneous sample: 98 twelve-year-old
English schoolgirls who
completed their exams at end of term. These students received
instruction concerning various astronomical
topics, including phases of the Moon. This instruction was largely a
textbook-based curriculum and
lecture, but also included simulations of the Moon phases with the use
of globes, lights, and tennis balls.
The exam questions required that the students use their knowledge of
Moon phases in various situations.
For example, the students were asked to consider the "period of Earth
days from Sunrise to Sunrise on the
Moon" (825). The students were also questioned about the "dark side of
the Moon" (a misnomer, as all
sides of the Moon receive sunlight at some point during the Moon's
orbit around the Earth). The results of
this study indicated the high prevalence of misconceptions, as only 40%
of the students correctly answered
questions about the "dark side of the Moon," and only 35% of the
students correctly answered questions
about the length of daylight on the Moon. Dove interpreted these
results as critical of a textbook-centered
curriculum, pointing out that many textbooks use ambiguous
two-dimensional images of the
Earth-Moon-Sun system to represent three-dimensional models. This
ambiguity of models and images
leads to difficulties when students are asked to change perspectives.
Dove indicated in this study that
many astronomical terms are misleading, citing the term quarter Moon,
which signifies that half of the
Moon is lit up as viewed from Earth. Dove's recommendations include
activity-based instruction to help
overcome the curricular obstacles.
During his work as a middle school teacher, Rider (2002) carried out
semistructured interviews with 32 of
his students who had not received any recent instruction on the topic
of the Moon's phases. His paper,
"Perceptions about Moon Phases," summarized common ideas held by these
students as they related to
general knowledge about Moon phases and three-dimensional modeling of
the phases. He concluded,
"While students have bits and pieces of correct information, very few
correctly understand the concepts
behind Moon phases" (50). From this quick summary, Rider recommended a
constructivist approach to
instruction for the topic. "The important thing is to provide as many
different types of activities as possible
and to allow students a chance to reflect on what they have observed
and to compare their evidence with
their original concepts" (51). The educator claimed that student
learning about the phases of the Moon
could be enhanced through activities that allow for self-reflection.
Baxter (1989) administered interviews about astronomical phenomena,
including phases of the Moon, to
20 students aged 9 to 16. Baxter's interview sample included five
groups of students in specific age
groups: 9-10 years old, 11-12 years old, 13-14 years old, and
15-16 years old. Baxter's sample of
students included an equal number of girls and boys. An analysis of
results revealed the prevalence of five
notions common to students' understanding about the phases of the
Moon. These included:
Notion 1. Clouds cover the part of the Moon that we cannot see.
Notion 2. Planets cast shadows on the part of the Moon that we cannot
see.
Notion 3. The shadow of the Sun falls on the Moon, blocking our view of
it.
Notion 4. The shadow of the Earth falls on the Moon, blocking our view
of it.
Notion 5. A portion of the illuminated side of the Moon is visible from
Earth.
Notion 5 is the modern scientific model for lunar phases. This study
helped define common ideas that
students held about the cause of the phases of the Moon and showed the
prevalence of misconceptions.
The study's participants most commonly held Notion 4 at all ages. In
fact, students ages 13-16 held either
Notion 4 or 5, though the majority subscribed to Notion 4.
Phillip Sadler, the primary researcher involved in creating the Private
Universe video, completed a
research study for his doctoral dissertation (1992) that investigated
1,414 high school earth science and
astronomy students' responses to a general astronomy questionnaire.
Like the work reported above, he
found that most students held misconceptions about astronomical
phenomena, including phases of the
Moon. The mean number of correct answers was only 34%. Sadler's
research considered the impact of
schooling and demographics on the test results, and he later analyzed
the effect of different distracters on
the responses to the multiple-choice questions (1996). He found that as
students matured and learned more
about a particular topic, their preference for certain incorrect
explanations increased. When these
distracters were present, the number of incorrect answers to the
question actually increased as students
started to learn about the topic. Sadler argued that even though these
responses were incorrect, they
represented a more sophisticated understanding of the phenomenon. In
other words, students' mistakes can
be an important part of the learning process.
Schoon (1992) administered a questionnaire to 1,213 participants in a
cross-age study that included 307
seventh graders, 340 11th graders, 226 college students, and 92
tradespeople. Overall, Schoon found that
"the holding of alternative conceptions in the Earth and space sciences
was widespread" (213). Like
Sadler, Schoon also analyzed which distracters were selected.
Alternative concepts were labeled as
primary ("chosen more often than scientifically acceptable
conceptions"), secondary ("chosen less often
than scientifically acceptable conceptions"), and functional ("could
interfere with one's ability to function
in society"). He also analyzed results by gender, race/ethnicity,
educational experience, and geographic
location. Schoon found significant difference "only between the college
level and the fifth and eighth
grades" (213). Among the respondents, "students who have taken Earth
science classes subscribed to
slightly fewer alternative conceptions than those who have not" (213).
Additionally, Schoon's
questionnaire identified primary alternative conceptions that are
relevant to students' understanding of the
phases of the Moon:
"When we have a full Moon, people on the same night in Australia have a
different phase of the
Moon." (52.9 % of total respondents gave this incorrect response.)
"The different phases of the Moon are caused by the shadow of Earth
falling on the Moon." (48.1%
incorrect)
Secondary alternative conceptions were related to the period of the
Moon's orbit and the source of
Moonlight. Schoon's recommendations for astronomy instruction called
for the use of direct observations,
classroom discussions, and a review of the history of the scientific
topic. He argued that students must be
aware of the alternative conceptions that they hold, concluding, "For
many students, the manipulation of
physical materials, as well as the discoveries they made for
themselves, help the retention of information"
(214).
2.4 Teaching and Learning the Phases of the Moon: Adult Learners
Researchers in astronomy education have also considered adults'
understandings about the phases of the
Moon. Callison and Wright (1993) tested an instructional method that
emphasized the use of models of the
Earth-Moon-Sun system with a group of preservice elementary teachers.
The researchers divided their
group of 76 participants into four sections and administered the
experimental instruction to three sections.
Before instruction, all participants were interviewed regarding their
prior knowledge of the subject and
completed tests to assess their spatial and reasoning ability.
The Callison and Wright study identified a majority of preservice
teachers in their sample with
misconceptions about the phases of the Moon. However, the experimental
instructional method
significantly impacted the three experimental groups. The control
group, which received instruction about
the Moon's phases without the help of models, did not improve their
results. The participants' scores on
spatial and reasoning tests did not significantly relate to their
improvement in understanding the phases of
the Moon after instruction. The researchers concluded that the use of
physical models when teaching the
phases of the Moon can significantly improve instruction.
Bisard and colleagues (1994) conducted a cross-age study using a
general science questionnaire. The
study's sample included 708 participants ranging from middle school
students to university students. This
latter population consisted of students with a strong science
background, and a small sample of preservice
teachers. The results of the study showed a large number of
misconceptions among all participants with
regard to astronomical concepts, including a score of 39.2% for the
question related to the phases of the
Moon. The researchers found test scores to be positively correlated
with age, except for the preservice
general elementary teachers, whose scores were dramatically lower than
others of their age. This group of
future teachers scored just above then-middle school students'
results. The authors expressed significant
concern with these findings: "This suggests that future general
elementary teachers seem to have about as
many misconceptions concerning the topics covered in this survey as do
typical middle school students"
(40).
Schoon's 1995 study of 122 preservice teachers in the American
Midwest and their conceptions of the
Moon phases used a questionnaire and found that many held the same
misconceptions as primary school
students. Among his findings, he reported that 62.3% of his survey
respondents believed that the phases of
the Moon are caused by the Earth's shadow. When subjects were asked
about the origin of their
misconceptions, Schoon reported that four common sources for erroneous
beliefs about the nature of lunar
phases included school science lessons, "logical" figuring of the
solution, the media, and folklore.
Parker and Heywood (1998) focused on the British education system.
Their survey included three groups:
two sections of preservice teachers and a small third group of
in-service teachers. They asked their sample
groups to use a blank piece of paper to map and demonstrate the causal
relationships within the
Earth-Moon-Sun system to produce the observed phases of the Moon via
annotated drawings. These
drawings were then categorized according to common schema and were
developed into six categories of
response. They found that misconceptions regarding the Moon's phases
were both common and similar to
misconceptions widely held by students.
A recent study by Trundle, Atwood, and Christopher (2002) provided
important details for understanding
preservice teachers' knowledge about the phases of the Moon. The
research questions that guided the
study were:
Before instruction, what are the types of conceptual understandings
held by elementary preservice
teachers about the cause of the Moon phases?
How do elementary preservice teachers' conceptual understandings of
Moon phases differ after
completion of instruction on this topic?
On the cause of Moon phases, how do the conceptual understandings of
elementary preservice
teachers who completed the instruction compare to those who did not?
Does using a three-dimensional model or making a two-dimensional
drawing during pre- instruction
interviews have instructional value? (636)
Subjects of the study were 78 preservice elementary teachers enrolled
in an undergraduate science
education course. The subjects were divided into four groups. Three
groups received the experimental
treatment. Two of the experimental groups were administered pre- and
post instruction interviews. The
third group received only postinstruction interviews. The fourth group
received textbook-based instruction
and postinstruction interviews. The experimental treatment was based on
Lillian McDermott's Physics by
Inquiry, a highly regarded and well-researched curriculum based on
constructivist learning theory. The
experimental treatment used students' observations, group discussion,
and the creation of physical models.
Participants' responses to the semistructured interviews were coded
with respect to their scientific
understanding of the phases of the Moon. Preinstruction interviews
revealed a large number of alternative
conceptions about the phases of the Moon. Postinstruction interviews
supported the conclusion that "after
instruction, most participants showed evidence of holding a scientific
conception or of showing more
scientific fragments of understanding than they had shown before
instruction" (Trundle et al. 2002, 653).
Furthermore, preservice teachers in the experimental groups held fewer
misconceptions about the Moon's
phases after instruction than did those in the control group. Finally,
the use of models in the preinstruction
interviews did not seem to affect the outcome. The inferences that can
be drawn from this study are very
strong given the rigorous experimental design employed by the
researchers.
The following summaries describe techniques for teaching adults about
Moon phases and eclipses, but do
not provide evidence of educational effectiveness.
It is difficult to say for certain who first introduced methods for
teaching about Moon phases and eclipses
based on constructivist learning theory. It is certain, however, that
one of the most influential educators
who pioneered the application of Piaget's theories to astronomy
teaching has been Dennis Schatz. His
astronomy teacher's workshop guide, with coauthors Fraknoi, Robbins,
and Smith (1978), presented an
activity in which students are shown a model of Mars with its two
moons, Phobos and Demos. They are
asked to draw the phases of both moons as they would appear to an
observer on Mars. When students take
turns walking over to the model and looking at the moons from the
position of Mars, nearly all are
surprised to see that their drawings were wrong, with most being
reversed left to right. The activity
emphasizes how difficult it is to see the world (and moon phases in
particular) from some else's point of
view, even with the aid of a concrete model.
Schatz's curriculum resource for elementary and middle school
teachers, with coauthor Cooper (1994),
provides a series of activities based on constructivist learning
theory. In the first activity, learners arrange
a sequence of photos of Moon phases in the order that they think they
will appear. Students then make a
record of actual Moon phases over a month's time to see if they were
right. This method is consistent with
the theory that if students make their initial ideas explicit, it will
be easier for them to extinguish any
misconceptions when they compare their expectations with the real
world. Finally, the students model
Moon phases and eclipses by observing a ball (representing the Moon)
lit by a lamp with a bare bulb
(representing the Sun), using an approach similar to that described in
section 1.4.2. That method of giving
each student a model Moon was codeveloped in the early 1970s by Dennis
Schatz and Larry Moscotti,
then a planetarium director in Hibbing, Minnesota.
Duckworth (1987) used a Moon journal investigation with adult learners
to illustrate two aspects of
teaching.
The first is to put the student in contact with phenomena related to
the area to be studied-the real
thing, not books or lectures about it-and to help them notice what is
interesting; to engage them so
they will continue to think and wonder about it. The second is to have
students try to explain the
sense they are making, and, instead of explaining things to students,
to try to understand their sense.
These two aspects are, of course, interdependent: When people are
engaged in a matter, they try to
explain it and in order to explain it they seek out more phenomena that
will shed light on it. (123)
Duckworth's constructivist-oriented methods included varied attempts
to help her students make sense of
the phases of the Moon. She firmly believed that students must
construct their own knowledge in order for
this new information to become meaningful and therefore retained.
Students compiled their observations
and worked in collaborative discussions to describe the Earth-Moon-Sun
system and to explicate their
ideas. This method, according to Duckworth, led to students who
achieved greater clarity of thought, who
determined for themselves what they wished to understand for the
lesson, who were independent, who
learned from each other, and who had their own thoughts taken
seriously.
Nissani's 1994 description of his undergraduate assignment for
learning Moon phases emphasized that his
students arrive in an interdisciplinary college science course without
a working knowledge of the Moon's
phases. His activity included students making Moon observations. He
noted that students were expected to
independently derive their conclusions from their own observations
without the benefit of reference texts.
He wrote, "inaccessibility of the answer is helpful; the text we use
says nothing about the phases of the
Moon. But it is even more important to encourage students to go it
alone and to assure them that they are
not expected to come up with a 'correct' answer and . . . they will
be graded on the basis of effort,
intellectual coherence, and creativity" (26). Nissani pointed to a
critical issue: the tension between
authentic inquiry and the pressure to grade students by commonly
established means or methods. His
paper included the complete inquiry activity of Moon observation,
including step-by-step instructions for
students.
van Zee's 2000 study of scientific discourse during a Moon
investigation included a cross-section of adult
learners, including undergraduates, graduate students, and professors
who chose to participate in the
constructivist-based inquiry activity. Her analysis focused on the
manner in which the science knowledge
was generated within the constructivist framework of the course, but
the subject under consideration from
this diverse group was the phases of the Moon. Her hopes included the
possibility that the course would
work "to develop shared understanding through discussion" (115) and to
shed light on the nature of
science as a product of discourse. The study was guided by the
following research questions:
1. What aspects of the students' discourse indicated inquiry
learning?
2. What kinds of questions do students ask each other during an inquiry
discussion?
3. How do these students collaborate in making sense of their
observations and interpretations?
Among her findings, the author noted that her role as an instructor was
affected by the stated goal that the
inquiry under discussion would be entirely student-generated. As an
instructor, van Zee chose not to
respond to student questions directly and avoided didactic teaching.
She noted that her quietness in this
regard had three aspects: to wait before and after students spoke, to
listen to the details of others'
sense-making, and to withhold her own opinions on the nature of what
was said. She detailed two modes
of discussion: true dialogue, in which students talk with each other
about what they think, and progressive
discourse, in which clarifications are made and doubts are resolved. It
is important to note that this study
presented a course that had no astronomy-based science subject goals.
As such, classroom authority was
distributed within the group of adult learners, and there were no
stated learning outcomes related to
curriculum.
Abell, Martini, and George (2001) used a Moon phase investigation as an
activity to deepen preservice
teachers' understanding of the nature of science (NOS). This study
collected data through questionnaires,
semistructured interviews, field note observations, and analysis of the
documents generated by the class.
Abell claimed that the Moon journal process parallels the development
of other science activities by
allowing students to make observations and collect and record data.
Yet, in trying to teach an appreciation
for the way in which science knowledge is generated, Abell discovered a
tension with the science content
of the subject. She found that only one student in her group of
elementary education preservice teachers
responded in terms of science as a collaborative effort. Abell noted,
"Our findings show that student
appreciation of the empirical, inventive, and social features of the
NOS was limited primarily to
processing their own learning, rather than applying their conceptions
to the activities of scientists" (1106).
In a later work, Abell and colleagues (2002) described a Moon phases
activity for preservice teachers in an
elementary education methods class in which the goals included helping
students to understand the phases
of the Moon and their own learning, to enhance their understanding of
the nature of science, and to have
students evaluate their presumptions related to science teaching and
learning. Abell and colleagues
included a description of the "puzzlers" used to direct student inquiry
during the Moon phases project.
Suzuki's work (2002) documented sophmore-level education majors in
Japan as they worked on projects
to teach the phases of the Moon for elementary students. The study
included a focus on learning science
through discussion and specifically mentioned that students at the
elementary level have difficulty
visualizing the Earth-Moon-Sun in three dimensions. Additionally, this
paper mentioned that younger
students build models based on their own everyday observations and that
older students begin to
synthesize their experience-based models with culturally accepted
models. The model proposed by the
course syllabus started with getting oriented and sharing observations.
Students then compared their
observations through time as the phases of the Moon evolved over a
semester. Models of the system were
later introduced, which allowed students to replicate the lunar phases
using a globe and a flashlight.
Suzuki's paper included self-report data and claimed that the group
of adult learners had no initial
difficulty with confusing the phases of the Moon with the Earth's
shadow, but that there was a common
assumption among the students to only look for the Moon during
nighttime hours.


[..]
deve dipendere dal fato che per il mondo anglofono la didattica di sta roba 
è piu istintivae radicata che da noi;
in fondo gli "Orreys" li hanno inventati loro ( i britanni ) sulla scorta 
della loro rivoluzione scientifica etc etc.
Io ancora ricordo i buffi disegnini - falci, mezzelune, lune piene  e coì 
via - del sussidiario delle elementari, che si " dovevano imparare a 
memoria"
Per me il metodo migliore è quello induttivo
Prendi un ragazzino di 8 - 10 anni e, dall' inizio del mese lunare,  fagli 
( magari casualmente ) osservare la posizione della luna al tramonto. Poi 
chiedergli il perchè.
Dopo un pò di giorni  magari  gli si fa fare un pò tardi la sera, ne vale la 
pena.
Dopo un pò ,e con qualche mimima spiegazione ,  può venirgli  l'instinto di 
"capire" la posizione del sole guardando la luna, ed il gioco è fatto.
E mica solo quello delle fasi; tanto per dire gli puoi far fare il gioco del 
dito mignolo sovrapposto, del diametro in un ora, dell'occultazione se 
capita, etc etc
 Per me i giochi con palloni e palline da tennis devono venire dopo questa 
fase, e non prima.

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