Physics KS3/GCSE: Why is fire hot?

Greg Foot explains that for things to burn they must be a fuel and have both heat and oxygen for the chemical reaction to take place.

He demonstrates how liquid oxygen can speed up the process of combustion, releasing energy in the form of additional heat and light. Greg then shows that water is very good at absorbing heat energy.

He explains that because the human body contains 73% water, this can protect it from burning provided the exposure to the heat is for a very short period time.

He demonstrates this by heating water in a balloon and by walking on a bed of hot coals.

Teacher Notes

This short film could be useful for students when discussing chemical reactions and the ‘fuel triangle’. Students could investigate what is required for the process of combustion to take place.

They could perform simple experiments on burning fuel such as magnesium ribbon and investigate conservation of mass and the products of combustion.

Curriculum Notes

These short films will be relevant for teaching physics and chemistry at both KS3 and KS4 in England, Wales and Northern Ireland and National 4/5 in Scotland.

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