Question 5
Work in pairs to carry out this experiment to find out how light travels (Figure 10.8). You will need three identical pieces of cardboard with a hole in the centre, a candle and matches.
1. Place the candle on a table and light it.
2. Arrange the three pieces of cardboard in a line between you and the candle. You can use stands or get friends to hold them. Make sure that the holes in the pieces of cardboard are aligned.
3. Look through the hole in the first piece of cardboard.
4. Now move the middle piece of cardboard so that the hole is not in line with the others. Look through the first hole again. Do the same with the third piece of cardboard.
Caution: Be careful when you work with an open flame. Keep all other objects away from it so that they do not catch fire.
Note: Instead of using a candle, you could use any well-lit object. All light travels in straight lines. It does not matter if the light is coming directly from a source or has been reflected from an object.
What did you see the first time you looked through the hole?
1. Place the candle on a table and light it.
2. Arrange the three pieces of cardboard in a line between you and the candle. You can use stands or get friends to hold them. Make sure that the holes in the pieces of cardboard are aligned.
3. Look through the hole in the first piece of cardboard.
4. Now move the middle piece of cardboard so that the hole is not in line with the others. Look through the first hole again. Do the same with the third piece of cardboard.
Caution: Be careful when you work with an open flame. Keep all other objects away from it so that they do not catch fire.
Note: Instead of using a candle, you could use any well-lit object. All light travels in straight lines. It does not matter if the light is coming directly from a source or has been reflected from an object.
What did you see the first time you looked through the hole?
