What is gravity?

• Gravity is a force that exists everywhere. It pulls all things with mass or energy toward one another.

• We commonly experience gravity by being pulled downwards by the Earth.

• Gravity keeps all of the planets (including Earth) in orbit around the Sun. It also keeps the Moon in orbit around the Earth.

Gravitational forces pull all objects together.

The greater the masses of the objects, the greater the force. The force due to gravity is also stronger when objects are closer together.

Although every object (including you!) exerts a gravitational pull on every other object, it is not easy to measure unless one of the objects is really, really big. The Earth, for example, is massive enough for the force due to gravity to be noticed.

Gravity on Earth

When an object falls toward the Earth it gets faster and faster.

As it falls, air resistance (another force), builds up to stop it moving as quickly. Air resistance is also increased if the object’s surface area is greater.

Some objects fall differently depending on how gravity and air resistance interact.

A feather, for example, is light and has a large surface area, meaning it will fall to the ground slowly.

Sky divers know gravity will make them fall to the ground quickly. Opening a parachute increases their surface area and air resistance, allowing them to slow down enough to land safely.

Gravity is everywhere. Just as a stone, feather or skydiver fall to the Earth because of gravity, so the Earth is pulled towards the Sun because of gravity. Gravity also keeps the Earth and all the planets in orbit about the Sun.

Gravity quiz

Find out how much you know in the quick science quiz!