Question 81
Activity 3.3.2: Bottle racers. Work in pairs. Use an empty plastic bottle with a small hole in the lid and another in the base, a paperclip, elastic band and pencil or stick. Attach the paperclip to one end of the elastic band; pass the band through the base into the bottle, then through the lid. Put the pencil through the free end and replace the lid. Rotate the pencil once, lay the bottle on its side and release it. It should not move. Find the number of turns needed to make it move.

You could extend this activity by finding the number of times the pencil must be rotated to make the bottle move up a slope.

You could extend this activity by finding the number of times the pencil must be rotated to make the bottle move up a slope.
