What is gravity?

Gravity is an invisible force that pulls objects toward each other. Everything that has mass has gravity. However, very large objects such as planets and stars, have much greater gravity than small objects. This is because these larger objects have more mass. 

Remember: A force is a push or pull on an object. Forces can cause an objects to speed up, slow down or change direction. Gravity is a force which pulls on objects.

How does gravity work?

If you hold a ball over your head and then let go of it what will happen? The ball will fall to the ground. Why doesn’t it move sideways? Why doesnt it float up into the sky? It is because the earth’s gravity pulls the ball down. When it rains, raindrops leave the clouds and fall down to the ground. Earth’s gravity is pulling the raindrops down.

If you jump up, earth’s gravity quickly pulls you back down to the ground. If gravity did not exist we would all just float off into space. Our atmosphere, the water in our rivers and oceans and most other things on earth would float off into space too.

^{As soon as these skydivers jump out of the plane, gravity starts pulling them down toward the ground.}

Gravity is powerful

The earth’s gravity does not just work on objects that are actually on earth. Earth’s gravity is so strong that it pulls on our moon and prevents it from moving away from the earth.

^{Without gravity, earth would not have a moon.}

The sun is much larger than all the planets in our solar system. The sun’s gravity is so strong that it pulls on the earth and the other planets in our solar system and prevents them from moving away. If gravity was suddenly turned off, all the planets would move away from the sun. 

^{The planets cannot move away from the sun because of the sun’s gravity.}