You will need

• Candle
• Matches or lighter
• 3 Jars of different sizes
• Heatproof base, for example a ceramic plate
• Stopwatch/timer (your mobile phone will do)

What to do

1. Put the candle on the heatproof base and light it.
2. Put the smallest jar upside down over the candle and start the timer.
3. Time how long it takes for the candle to go out and record the time.
4. Repeat steps 2 and 3 for the medium sized jar and the large jar.
5. Record for each candle how long it burns. Under which jar does the candle burn longest?

Background

Oxygen is needed for a fire to burn. This is also true for candles. The oxygen is normally supplied by the air.

When placing a jar over the candle, the amount of oxygen for the candle is limited. The candle goes out when all oxygen in the jar is used up. The amount of oxygen depends on the size of the jar.

Under which jar does the candle burn longest? Why do you think that is?

You can watch a video of this experiment here: