Susan Zimmerman., age 12, of Vancouver, B.C., .oar her question:

What do they use to propel a rocket?

The modern rocket is propelled by chemical fuels. One of these chemicals is kerosene, or something like it, and the other is liquid oxygen, The two different fuels are loaded onto the rocket in two carefully separated compartments. The fun begins when small amounts of each chemical run down tubes and meet in the back of the rocket.

The result is a continuing series of explosions. Hot gases are forced out in a trail behind the rocket and the reaction to these expanding gases forces the rocket forward. We call this a chemical rocket because it uses chemical fuel. The rocket of the future will most likely use other forms of  energy as fuel.