Experiment No. 4
What you have to do:
1) Draw a spiral snake on a piece of card and colour it in.
2) Carefully cut it out.
3) Staple a length of thread on to the tail of the snake.
4) Now, hold your snake above a very hot radiator and watch what happens.
Result: The snake twirls around above the radiator
Conclusion: The heat off the radiator rises and therefore it causes your snake to spin.
Try this: Tissue paper is very light so try placing a small piece on to a radiator and see if you can get the paper to settle. If the heater is hot enough, the tissue will not stay in place - it will literally "fly away".