Working Principle of Rocket:
A rocket or a jet plane works on the principle of conservation of momentum. In a rocket or a jet engine, there is a combination chamber with a small aperture H at its rear end. Solid or liquid fuel is ignited in the chamber. As a result of combustion, a large amount of spent fuel, in gaseous form, escapes at a high velocity through the exhaust. This provides a forward thrust to the rocket.
Compartment F is filled with fuel like liquid hydrogen, kerosene, etc. Compartment O contains oxidants, whose function is to supply oxygen for combustion. Fuel can burn only in the presence of an oxidant. Liquid oxygen, ozone, hydrogen peroxide, etc are used as oxidants. The fuel and the oxidant are carried in a liquid or solid state because they occupy less space in comparison to the gaseous state.
They are pumped into the combustion chamber where the mixture is burnt. The gas formed due to the combustion is ejected at a very high velocity, which sets the rocket in motion. At the head of the rocket, P satellites, spaceships, etc are carried. Oxidants are carried in a rocket because there is no air in space.
Working Principle of Jet Engine:
A jet engine can’t fly where there is no air. Because oxygen from the air is used for combustion. A jet engine which in flight, sucks in air from the front. Using a compression pump, the air is introduced into the combustion chamber and fuel is burnt at high pressure.
Liquid fuel is used in a jet plane. Gases generated on combustion rush out through the rear end of the engine and the plane moves forward at a great speed. A jet plane can fly 10 to 20 km above the earth’s surface. Modern jet planes can fly at a speed higher than the speed of sound.