We just learned about the Solid and Liquid Rocket Propellants.
Another type of propellant is Gas Rocket Propellant.
This type of propellant is the easiest to control the exact amount of fuel burned and the exact amount of thrust created.
To keep the gas stored safely and under pressure, the fuel tank in the rocket has to be very heavy, so gas is not usually used for the bigger rockets.
Gas has been used the most for little rockets that just change the direction of a rocket to the left or right.
Small rocket thrusters called Vernier Thrusters were on the sides of rockets like the SM-65 Atlas, to help it go in the right direction.
(from: wikipedia - vernier thruster)
Kid Facts - Blast from the past: Swarf
