The strength of the force depends on the mass of the object. (The mass is the amount of stuff or matter that makes up an object)

Heavier objects have more mass so they have a bigger force of gravity.

For example: A ball thrown into the air falls back to Earth. This is because the Earth has more mass than the ball, so the Earth's gravitational pull is greater than that of the ball. (The ball is pulling the Earth upwards but because it is so much smaller than the Earth its effect cannot be measured)

The further apart two objects are, the less the gravitational pull between them.

What does gravity do?

The gravity of the Sun and the gravity of the Moon pulls the Earth's ocean tides back and forth.

Gravity holds us and the buildings around us onto the Earth as the planet spins on its axis.

Gravity holds the planets in orbit around the Sun.  

It holds satellites in orbit around the Earth

Black holes are places where the gravitational pull is so strong that even light can't escape. The black hole pulls everything into its centre. Scientists believe that there are may be millions of black holes in our solar system.

Read about black holes on kidcyber here.

Isaac Newton

Isaac Newston

Isaac Newton (1642 - 1727) was the first person to explain gravity. He did it in 1687.

It is said that Newton first started to think about gravity when he saw an apple fall from a tree. He wondered why it fell down, and not up!

You can read about him here.

Understanding Gravity