Background

:

The last chapter in the Form three syllabus, “The Universe”, is lacking in experiments and teaching aids. Many topics in this chapter are taught theoretically or by using simple charts. The following concepts are often taught isolated from one another:

1.  Changes of moon phases.

2. High tide and low tide.

3. Eclipses.

4. Lunar calendar.

In fact, all these concepts are related with one another. The lunar calendar was used by our ancestors. Now it is still being used by us, especially in fixing the dates for religious festivals or other activities like fishing. The creation of the lunar calendar by various races in the past has shown the scientific wisdom of mankind and this should be appreciated. The lunar calendar is derived from the observation on the duration of the revolution of the moon around the earth. The revolution of the moon also brings about the phenomena of the tides and the eclipses that we experience on earth. Hence, these concepts are interrelated. Therefore, helping pupils to understand this relation inevitably increase their appreciation in science. But at present moment there are no available teaching-learning materials related to this topic.

Objectives

:

1.  To enhance the prior knowledge of students and further translating what they have learnt about the concepts of the phenomena of “The Universe” into pictures.

2. To form a device illustrating the pictures of the above phenomena.

3.  To understand the lunar calendar date, which moon phase, what kind of tide and when eclipses can possibly occur.

4. To understand how the various concepts of “The Universe” are interrelated.

Benefits for teaching and learning process

:

[Refer 2-P1 and 2-P2]

1.  It is a student-centered lesson

2. Pupils can share what they have learnt in their science lesson with their family members.

3. The concepts learnt can help pupils to relate science to everyday life.

4. This is a simple and cheap teaching aid.

5. This activity can help pupils to study the interrelation of the above concepts especially for those who have not experienced tides before.

Apparatus/ materials

:

1. Beads

2. Wire

3. Cardboard (Black and White)

4. Paper (White, yellow, purple and blue)

5. Geometrical set

Construction of teaching aids

:

These materials are shown in pictures [Refer 2-P3]  

1. Earth
   Circular purple paper with radius 2 cm.

2. Moon
   Circular white paper with radius 0.75 cm.  

3. Sun  
   Circular yellow paper with radius 0.5 cm.  

4. Tide  
   Oval shape blue paper scaled with a 0.5 cm interval.  

5. Rotation disc
   Black circular cardboard with radius 10 cm and center labelled O.

6. Lunar calendar monthly dates. [Refer 2-P4]
   Consists of a series of numbers from 1 to 29 lined up a circle with outer radius of 9 cm and printed on a piece of paper. 

7. Front cover
   Rectangular black cardboard measuring 45 cm x 46 cm.

8. Back cover  
   Rectangular white cardboard measuring 45 cm x 46 cm  

9. Beads and the wire
   Two beads are used to hold the earth, the tide, the rotation discs and the back cover together by inserting a wire through the holes.  

    

Implementation of the teaching

:

1. Pupils are given a set of materials (the earth, the tide, the moon, the lunar monthly calendar date, the rotation discs, the sun, the front cover, the back cover, beads and wire).  They are requested to explore the making of the device, “Calendar Alive”, by following  the steps given below:}
   

2. Step 1  
   Gum the papers showing the tide, the moon on the rotation discs  as shown below. [Refer 2-D1 and 2-P5]
   

3. Step 2  [Refer 2-P6]
   The rotating disc is placed between the earth and the back cover. A   wire is inserted through all the holes and held in position by the beads at both ends.
   

4. Step 3  [Refer 2-P7]
   The lunar calendar monthly date is gummed onto the front cover enclosing the phases of the month and the sun is stuck at the middle of the outer edge. After that it is mounted onto the back cover.  
   

5. Step 4  [Refer 2-P6 and 2-P7]
   By rotating the rotation disc slowly, the following relationship can be investigated.
   i.    How can the monthly date of the lunar calendar be fixed by the phases of the moon?
   ii.   Changes in the height of the tide, is governed by the relative position of the moon and the sun. Thus the moon phases are related to the height of the high tide, which is varying at different times.
   iii.   Investigate the phases of the moon that eclipses can possibly occur.
   

6. Printed questionnaires are given to the pupils to guide them to  relate these concepts. The ability and the prior knowledge of the pupils should be taken into consideration when preparing the  questionnaire.

Suggestion for modification

:

1.     Use OHP to demonstrate the setting-up of the apparatus from Steps1-4.

2.     Explain to the students the relative sizes of the models for the earth, moon and sun (use ratio if possible) to avoid misconception.