Paragraph on “How does a rocket defy the force of gravity?” complete paragraph for Class 9, Class 10, Class 11 and Class 12

How does a rocket defy the force of gravity?

If you jump up as hard as you can you still fall down again very quickly. This is because of the pull of the earth’s gravity. If we want to `jump’ into space we need to push away from the earth so hard that gravity cannot pull us back.

To do this we use rockets. A rocket works by shooting hot gases out of the tail so that the rocket is thrust forwards. This is like a jet engine except that a rocket needs no air to make its fuel burn. It uses an explosive powder like that in a firework, or it carries its own liquid oxygen. This means a rocket even works in space. Rockets are so powerful that they can lift right away from the earth, against the force of gravity.

In 1957 Russia launched Sputnik I, the first artificial satellite. It was launched by a rocket and went into ‘orbit’ around the earth. This means that it was moving across the sky too fast to be pulled down so it swung round and round the earth like a ball on a string. The first man to fly in space was the Russian, Yuri Gagarin. In 1961, after being launched by a rocket, he made one orbit of the earth in Vostok I.