How does a candle burn?

Do you know what happens to make a candle burn? Well the Year 5 and 6 students and teachers thought they did. But we had to change our minds once we learnt what actually happens.

Most of us thought that the wick was burning and that the job of the wax was to hold up the wick and slow down its burning.

But this is actually what happens:

Burning a Candle
By Sarah - Year 6

It all starts with friction between the match head and the strip on the match box. This will make a flame. When you transfer the flame to the candle the heat starts to melt the candle wax. When the wax is melted it forms a dip in the candle, kind of like a crater. A tiny bit of the wax soaks up into the wick and travels upwards. This is called wicking up. When the wax gets to the top of the wick it turns into a gas. When the oxygen and the was gas combine it is a chemical reaction. This keeps the candle burning. The rest of the melted wax drips down the sides of the candle. As the candle wax gets further away from the flame it gets harder and harder until it solidifies. When you blow out the candle a whole lot of smoke rises from the candle letting off all the left over wax gas.

The Burning Candle
By Jesaiah - Year 6

I think the candle burns when the match melts enough was to be sucked up by the wick for the already burning flame on the wick to use as fuel. I think the oxygen in the air acts as a secondary fuel to keep the flame going. I know that when the flame melts the wax, the wax forms a crater-like pool. When the excess was in the pool flows over the edge it solidifies as it gets cooler down the candle. The wax also acts as a structure for the wick. The heat from the flame separates the molecules into a liquid by making them hyperactive. I think that as the molecules move further away they become a gas, which is what goes up the wick and fuels the flame. I know that the flame starts when the gas-wax has made it to the top of the wick then when it hits the oxygen the flame is the result of a chemical reaction.

We also observed the flame carefully and noticed that there are lots of different colours.

Picture from - http://www.educationalelectronicsusa.com/c/fuels-VIII.htm