11 Gravity

Gravity written by Dawn McMillan

forces Gravity is an invisible force of nature. A force is a push or a pull. Gravity is a pull. If you throw a stone in the air, it will fall down because it is pulled by the Earth's gravity. When you fall off your bike or spill your drink, gravity is at work! Gravity is what makes things fall down to Earth.

science It was a famous scientist, called Isaac Newton, who first thought about gravity. One day, when he was sitting under an apple tree, an apple fell on his head. He wondered why the apple fell down. Why didn't it go up, or sideways? This made him think that something pulled the apple down.

Earth Gravity is important to all living things because it keeps us in place on Earth. If gravity didn't pull us down, we would float off the planet. All our water would float off, too, and even the air that we need to breathe would float away!

weight Gravity pulls things closer to each other. If an apple falls off a tree, both Earth and the apple are pulling each other. But we don't notice the tiny pull of the apple because Earth is huge, and it has a very strong pull. When gravity pulls on your body, it is called weight. The further away from the centre of Earth you are, the less you weigh. If you were on a mountain top, you would weigh a little less.

particles Things like wood, stone, and water are made from very tiny particles. Even air is made up from little particles. We are also made from particles, but they are too small for us to see. The more particles something has, the more gravity pulls on it. That is what makes things feel heavy.