Complete an experiment using different sized glasses to see what happens to the flame under different conditions.
What you need:
- candles
- matches
- different sized glasses
What to do:
- Set out some candles in a line. You can use blu-tack to secure them to a surface if they do not have a large base.
- Light the candles.
- Turn over the glasses and put them over the top of the candles. This should all be done at one time.
- The candles will go out, with the one under the smallest glass going out first. If you cannot do many glasses at once, time how long the candle takes to go out under each different sized glass.
What happens:
Fire needs oxygen to burn. When a flame is in an enclosed space, it uses up all the oxygen. With no new oxygen to burn, the candle goes out. When the candle is under a small glass, it doesn’t have as much oxygen as when it is under a big glass. This means that it runs out of oxygen quicker and the flame goes out faster.