How to Explain Gravity to Kids | Fieldbook Learning

“Why do things fall down?” is one of the first big science questions a child asks. The honest short answer is: Earth pulls on everything, and that pull is called gravity. The rest of this post is about how to make that answer feel real at different ages.

Start with what they already know

Before explaining, ask: “What happens when I let go of this?” Drop a spoon, a sock, a ball. Everything falls. Then ask: “Has anything ever not fallen?” Balloons, birds and aeroplanes come up, which is a lovely opening. Those things are held up by something else (air, wings, lift). They are still being pulled down.

For ages 4 to 6: a pull you can feel

Say: “Earth is like a giant magnet for everything, but it pulls on all things, not just metal.” Strictly speaking, gravity is not magnetism, so a better version is: “Earth gives everything a pull toward the ground.” Let them:

Hold a bag of rice in one hand and an empty bag in the other. Which pulls down harder on the hand? You can feel gravity as weight.
Jump as high as they can and notice they always come back.
Drop things from a low height onto a soft surface.

You do not need to say more. A feeling for the pull comes before an explanation of it.

For ages 6 to 9: do heavy things fall faster?

Most children expect heavy things to fall faster. It is a very reasonable guess, because a feather falls slowly and a stone falls fast. Test it.

Drop two balls of different weight from the same height at the same moment. Use a tennis ball and a ball of scrunched paper of similar size, or a small stone and a larger one. An adult should watch for safe landing spots.
Listen for one landing sound or two.
Now drop a flat sheet of paper and a scrunched ball of the same paper. They differ, but the weight is the same, so something else is going on.

The “something else” is air. Air pushes back on a falling object, and a flat sheet catches more of it. When the air matters less, things of different weights fall together. Astronauts on the Moon, where there is almost no air, dropped a hammer and a feather and both landed together. Our lesson Do heavy things really fall faster? is a full investigation of this, and there is a blog post on the same question.

For ages 9 to 12: weight, mass and numbers

Older children can handle the difference between mass (how much stuff something has, measured in kilograms) and weight (how hard gravity pulls on it, measured in newtons). On Earth, a 1 kg object weighs roughly 10 newtons. On the Moon, where gravity is about one sixth as strong, the same object has the same mass and a much smaller weight.

Try these:

Measure the time a ball takes to fall from different heights using a phone timer. Many attempts are better than one.
Calculate the pattern. Falling twice as high does not take twice as long.
Ask what would change on the Moon, and what would not.

The post a kilogram of feathers or rocks: which weighs more? is a nice way into the idea that mass and volume are different things.

Common misconceptions

“There is no gravity in space.” Gravity is very much present on a space station. The astronauts float because they are falling around Earth together with the station. You can say, “They are always falling, and always missing the ground.”
“Gravity pulls only downwards.” It pulls toward the centre of Earth, which is “down” wherever you stand. People in Australia and people in Canada are both pulled to the same centre.
“Heavy things always fall faster.” Only when air gets in the way.
“Gravity is only on Earth.” The Moon, the Sun and everything with mass pulls on things.

Questions to ask

What would happen if gravity switched off for a second?
Why do we say a ball “wants” to go down? Does it want anything?
What else besides gravity pushes or pulls on a ball rolling along the floor?

This last one leads naturally to friction. The lesson Why does a ball stop rolling? is a good companion.

A short explanation you can borrow

“Everything with mass pulls on everything else. Earth has so much mass that its pull is the one we feel. That pull is called gravity. It is why things fall, why you have weight, and why the Moon goes around Earth instead of floating away.”

Where to go next

Try the forces and magnets unit for younger children, and the forces at work unit for ages nine and up. If you are new to teaching science at home, how to teach your child science at home with no background is a friendly place to start.