What is gravity?
Gravity is a pulling force that every big object, like Earth, uses to pull things toward its center. On Earth, gravity pulls us toward the ground so we don’t float away.
Step-by-step guide to gravity
- Imagine a planet pulling everything toward its center. That pull is gravity.
- Mass is how much stuff you have; weight is how hard gravity pulls on that stuff. They are related but not the same.
- Earth’s gravity near the surface is about 9.8 m/s^2. This helps us know how heavy something feels.
- Your mass stays the same on different planets, but your weight can change because gravity is stronger or weaker there.
What keeps us on the ground?
We stay on the ground because Earth's gravity pulls us down and the ground pushes back with a normal force. Together, they hold us in place.
Everyday examples
- When you drop a ball and a feather in still air, the ball lands first because air slows the feather.
- In space or in a vacuum, without air, objects fall at the same rate, no matter how heavy they are.
Weight on other planets
Planets with stronger gravity would make you heavier; with weaker gravity you would be lighter. Your mass never changes, only your weight changes with gravity.
Quick math tip
Weight = Mass × gravity. If your mass is 30 kg on Earth, your weight is about 30 × 9.8 ≈ 294 newtons.
Summary
Gravity is Earth’s pull that keeps us on the ground. Mass is how much stuff you have, and weight is how hard gravity pulls on that stuff.