Entry into Space
How can we overcome the Earth’s gravitational pull? Scientists have been working on this for a long time. It is only recently that they have been able to build machines powerful enough to get out of the Earth’s gravitational pull. Such machines are called space rockets. Their great speed and power help them to escape from the Earth’s gravitational pull and go into space.
Rockets
The powerful space rocket works along the same lines as a simple firework rocket. The firework rocket has a cylindrical body and a conical head. The body is packed with gunpowder which is the fuel. It is a mixture of chemicals that will burn rapidly to form hot gases.
At the base or foot of the rocket there is an opening or nozzle. A fuse hangs out like a tail from the nozzle. A long stick attached along the body serves to direct the rocket before the fuse is lighted.
When the gunpowder burns, hot gases rush out of the nozzle. The hot gases continue to rush out as long as the gunpowder burns. When these gases shoot downwards through the nozzle the rocket is pushed upwards. This is called jet propulsion. The simple experiment, shown in the picture, will help you to understand jet propulsion.
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