WHY?—

Hawera Star, Volume XLV, 25 July 1925, Page 18

WHY?—

Why is the Fire Hot ?

The heat that- we feel when we stand opposite a fire is of two kinds. Partly it is the heat in the air which the fire has made warm, and which we. feel against the skin. That heat has flowed into the air from the hot fire, but. by far the greater part of the heat we feel opposite the fire is what is called radiant heat., a thing which is exactly of tlie same nature, ns light, only that instead of seeing it we feel it hot. So our question is: What happens in the fire that makes it produce tlie heat of both kinds that- we feel I It will be quite plain to us that when heat is being produced something is being done, something is being made, and we know that the pow r er has to come from somewhere. It conies from the carbon in the coal and the oxygen in the air. They have energy and power locked up in them which are, so to speak, released when the carbon and oxygen combine to make the fire. The potential energy of the carbon and oxygen are changed, when they combine, iuto heat energy. This heat shows itself in a rapid motion, we suppose, of the matter in the fire. This communicates itself to the atoms of the air. making them hot, and starts the waves in the ether which we call radiant air.