Mass or weight
One stays. One changes.
On the Moon
A 1 kg object is taken from the Earth to the Moon.
What changes?
What this lesson covers
The idea
Mass, the amount of matter in an object, measured in g or kg, is the same everywhere; weight, the gravitational pull on it, varies slightly on Earth and greatly on other planets or the Moon.
On the Moon
A 1 kg object is taken from the Earth to the Moon.
What changes?
- Its weight changes, its mass stays
- Its mass changes
- Neither changes
Visit the bodies
Pick each place. Look at the mass and at the weight.
Mass stays, weight changes
The mass was always 1 kg, but the weight changed from place to place. The gravitational pull is different on each body.
Mass is the amount of matter in an object, in g or kg. It is the same everywhere. Weight is the gravitational force on the object. It varies slightly on the Earth, and greatly on the Moon and other planets.
- Place | Mass of the object | Weight of the object
- Earth | 1 kg | 10 N
- Moon | 1 kg | 1.6 N
- Mars | 1 kg | 3.8 N
- Venus | 1 kg | 9 N
- Jupiter | 1 kg | 25.4 N
Notes
Mass (g or kg) is the same everywhere. Weight is the gravitational pull on the object and changes from place to place.
Check yourself
A 1 kg object weighs 10 N on the Earth. What is its mass on the Moon?
Answer: 1 kg
The mass is 1 kg everywhere.
On which of these does the 1 kg object have the largest weight?
Which of these is the same everywhere?
What is the weight of the 1 kg object on the Moon?
- The Moon. The Moon has the smallest weight, 1.6 N.
- The Earth. On the Earth it is 10 N. On Jupiter it is 25.4 N.
- Jupiter — correct. Yes!
- Mass — correct. Yes!
- Weight. Weight changes from place to place.
- Both. Only mass is the same everywhere.
- 10 N. 10 N is its weight on the Earth.
- 1.6 N — correct. Yes!
- 1 kg. kg is a unit of mass. Weight is in newton.