Science
What is Weight?
Weight is the force of gravity pulling on an object's mass. Because it depends on gravity, weight changes with location — you weigh less on the Moon than on Earth — even though your mass (the matter in you) stays the same.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains weight.
Key things to understand
- 1Weight is a force: the pull of gravity on an object's mass (weight = mass × gravity).
- 2It's measured in newtons (N) scientifically, though everyday scales show it as kilograms.
- 3Weight changes with gravity — less on the Moon, more on Jupiter — while mass stays constant.
- 4A spring scale measures weight; a balance measures mass.
- 5In free fall or orbit, objects feel 'weightless' even though their mass is unchanged.
Frequently asked questions
- What's the difference between weight and mass?
- Mass is the amount of matter in an object and never changes; weight is the gravitational force on that mass and changes with location. Same mass on the Moon, but one-sixth the weight.
- Why do you weigh less on the Moon?
- Because the Moon's gravity is about one-sixth of Earth's. Weight depends on gravity, so weaker gravity means less weight — though your mass is identical.
- Is weight measured in kilograms?
- Everyday scales show kilograms, but scientifically weight is a force measured in newtons. Kilograms actually measure mass; the scale converts using Earth's gravity.