How Does a Rocket Engine Work?
You can make a simple rocket by filling a toy balloon with air and letting it go. Rockets work on the Newton’s principle that every action has an equal and opposite reaction. When your balloon flies away, the “action” is the air rushing out of the opening and the “reaction” is the forward flight of the balloon.
In a rocket, burning fuel creates hot gases that rush out of the tail, forcing the rocket to surge forward. It is this forward reaction that propels the rocket. Because the exhaust gases do not have air to push against, the rocket moves rapidly through outer space.
When the rocket burns fuel, it’s “throwing” the fuel downward, which causes the rocket to rise upward. Burning fuel increases the speed at which the fuel is thrown out of the rocket. The faster the fuel comes out of the rocket, the more force there is to push the rocket upward.
A rocket needs a lot of fuel in order to push it upward, which is one reason why rockets are so big. They need much of that space to carry all that fuel. The usual speed at which burning rocket fuel is pushed out of the rocket is between 5,000 and 10,000 miles per hour (8,046.5 to 16,093 kilometers per hour).