Materials Required:
- String
- Wooden dowel
- Tape
- 2 paper lunch bags
- Candle with stand
- Match box
Procedure:
- Tie a piece of string to the centre of a wooden dowel and attach the free end of the string to a support, such as the centre of a doorway. Tape equal lengths of string to the bottom of 2 paper lunch bags and tie these upside down to the ends of the dowel. Adjust the paper bags so that they may be balanced perfectly on the dowel.
- Hold one of the bags in its balanced position and ask your parent to light a candle and hold it under that bag for several seconds. When the candle is taken away, let go of the bag. The bag will rise.
This is what happens:
The candle flame heats the air inside the bag. This hot air is surrounded outside by cooler air. The cooler air is heavier than the hot air and lifts the bag of hot air upwards.
