Activity 1.

Aim: To demonstrate the rectilinear propagation of light.

Materials and apparatus
1. The pieces of cardboard with a hole in each.
2. Source of light, eg. a candle.

Procedures:
1. Put the pieces of cardboard with the holes in a straight line.
2. Arrange them to a distance of about 50 cm apart.
3. Place a lighted candle at one end of cardboard A. observe the light from behind cardboard C.
4. Now displace any one of the pieces of cardboard, eg. Cardboard B.



Observations
When observing from card C, the candle can be seen. Displacing any one of cardboards, the candle can no longer be seen as the holes are no longer in a straight line. This happens due to the fact that light travels in a straight line.


Activity 2.

Aim: To investigate transmission of light.
Materials
1. Sheet of paper
2. Sheet of glass
3. Tinted glass
4. Cardboard
5. Oil paper

Guiding questions
1. Which of the materials are opaque?
2. Which of the materials are transparent?