| Background
: |
As
far as our memory can trace, we are fascinated
by the astronomical phenomena around us. It is
a good step to introduce astronomy into our Form
Three Science Syllabus.
At
present, the concepts to taught in the Form Three
Science Syllabus are :
a)
The rotation of the earth causes day and night
as well as the rising and the setting of the sun,
moon and the stars.
b) The formation of the solar eclipse and the
lunar eclipse.
c) The occurrence of the four seasons is due to
the revolution of the earth around the sun and
the tilting of the earth's axis.
d) The calendar
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The
disadvantages of this method are:
a)
Students who are standing around the teacher are
observing the globe at different angels. Thus
they cannot get the same view as the teacher wanted
(refer 2-P1).
b) It is difficult for the teacher to maintain
the globe to be tilted at a fixed angle and at
the same time pointed to a specific direction
all the time. Any alteration of the two factors
will affect the result.
c) While the globe is being carried around the
lighted electric bulb, it is difficult for the
student to inter-relate the date, the position
of the earth, and the amount of light received
by the hemispheres and the name of the season
experienced by a particular area.
After
the lessons, students still have a vague concept
about how the four seasons are formed.
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At
the moment, teachers are using all the methods
suggested in the text book such as :
- Shining
a torch light on a globe to explain concept
(a) and concept (b) ( refer diagrams 2-D1 and
2-D2).
- Concept
(c) is taught by the help of a four seasons
formation chart (refer 2-D3) or by demonstration
by the teacher as shown in photograph 2-P1.
- The
two dimensional diagrams does not truly show
the amount of light received by each hemisphere.
- The
dates for the solstices and the equinoxes are
merely taught with facts only.
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| Moon-Earth-Sun
Carton Box Teaching Aids : |
- The
Moon-Earth-Sun Carton Box Teaching Aid is a
simple and cheap device made of carton box created
to overcome the above-mentioned problems.
-
It does cause light interference to other groups'
experiments.
-
It does not need a total dark room.
-
It can be used to study the above-mentioned
concepts.
- It
gives all the students visual aid and time allowance
to inter-relate the calendar with the four seasons.
-
It helps the students to understand how the
four seasons are formed and why the duration
of day and night changes with the four seasons
at a particular place.
-
It makes science lesson more interesting and
meaningful to our daily life.
-
Each student can have a hands-on experience.
-
Each student is given a chance to construct
the concepts in their mind.
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| Objectives
: |
- Students
are able to acquire new and hands-on experience
to understand more about the solar and lunar
eclipse, the day and night phenomena and the
formation of four seasons.
- Students
are undergoing and using the scientific skills
as well as the creative thinking skills to construct
better understanding of the above-mentioned
concepts.
- Students
are greatly encouraged to learn and do activities
in a small cooperative learning group.
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| Benefits
for Teaching- Learning Process : |
-
It enables each student to observe and to have
a hands-on experience in order to understand
the concept more clearly.
- Students
are greatly motivated and have fun whilst carrying
activities.
- The
teaching and learning will be more effective
and meaningful as the students can discuss and
relate the phenomena one by one.
- The
teaching aid is cheap and easy to build.
- Students
carry out the activities in a small group and
thus allowing more individual participation
in the activities (See 2-P5).
- It
does not cause light interference to other groups
since the light source is not strong and is
confined to the box only.
- The
teaching aid seems to be useful, as most of
the students do not have the opportunity to
experience the four seasons and the long nights
in winter.
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| Materials
/ Apparatus : |
- A
carton box
-
Black paper
-
Glue
-
5 polystyrene balls
-
1 electric bulb (6V)
-
Electric wire
-
Battery or power pack
-
8 metal rods (12.5 cm)
-
Coloured pins
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| Construction
of Teaching Aids : |
The
teaching aids are merely made of simple and cheap
materials that are always available in a local shop
or stationer. Some are used materials.
1.
The teaching aids consist of three main parts.They
are :
- a
black carton box
- the
stands and
- models
of the moon (a plasticine ball), the earth (a
polystyrene ball) and the sun (an electric bulb
)
2.
Black carton box (refer 2-P2), which the inner
surface is glued with black paper to prevent or
reduce reflection of light.
3. The stands (refer 2-P2) is made up of three
layers (cut out from a carton box) and stuck together
with the middle one having a part being cut off
at an angle of 66.50 with the horizontal line
(refer 2-D4).
4. The models of the moon, the earth and the sun
are constructed as shown in 2-D5.
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| Implementation
of the Teaching : |
-
Students have to insert the earth axis into
the stands.
- When
the electric bulb is switched on, certain area
on the surface of the polystyrene ball will
be lighted up.
- Insert
a coloured pin on the surface of the polystyrene
ball to represent human being and rotate the
earth's axis. The formation of day and night,
the phenomenon of the position of the sun, the
moon and the star experienced by human being
(represented by the colour pin) can be studied
(refer 2-P3 and 2-P4).
- Student
can also observe the formation of the eclipses
by rotating the plasticine ball around the polystyrene
ball.
- Each
student of the group can do the experiment on
his own since there are eight polystyrene balls
available in the box. (Refer 2-P5).
- Students
can investigate and compare the gradual change
in the distribution of light at the Northern
Atmosphere and the Southern Atmosphere by observing
the polystyrene balls.
- Students
can calculate the dates of the solstices and
equinoxes by fixing one of the dates for them.
- Students
can also observe the difference between the
duration of time for the day and night at one
particular place during the different seasons
by rotating the earth's axis.
- Moon-earth-sun
carton box teaching aid can be used together
with printed out questionnaires as a guard especially
for slow students or students with low imaginary
power.
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| Suggestion
for modification : |
The
bulb used for this model should be made translucent.
If the translucent bulb is not available, translucent
paper can be used to cover it.
This
model explains well about the 4 seasons, day and
night and the eclipse of the moon. For the purpose
of day and night, teacher may use light from the
OHP for better ray effect on the earth model.
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