CoachA fuel is a material that can burn and give out heat and light: wood, paper, coal, candle wax, the gas of a cooker, petrol, heating oil.
Examples
Example 5.2 (Solid, liquid and gas fuels)
Wood, paper, coal and candle wax are solid fuels. Petrol and heating oil are liquid fuels. The gas of a kitchen cooker and the gas in a lighter are gas fuels.
Example 5.5 (Lighting a match)
A match head is rubbed on the side of its box. The rubbing heats it enough to start it burning: the heat side of the triangle. The wood of the match is the fuel, and the air brings the oxygen.
Example 5.6 (Blowing on embers)
Glowing embers that seem almost dead burst into flame again when someone blows on them: the blowing brings more air, and so more oxygen, to the fuel that is still hot.