Kathy McMahon, age 12 of Utica, N.Y., for her question:

What is fire made of?

What is a train ride made of? Actually it is an event in which certain objects are involved and certain things happen. The ride moves you from one place to another. Fire, too, is an event in which certain objects are involved and certain things happen. The objects involved in a fire are fuels. What happens is that the chemicals in the fuels are changed to other chemicals and heat energy is given off in the process.

Fuel, like everything else, is made from tiny molecules. The molecules are tightly bound bundles of atoms. In the heat of the fire, the molecules of fuel are broken apart and the energy which bound them is given off as heat. The separate atoms go off into the air and form water vapor and carbon dioxide. We call this event a chemical change, or chemical reaction.