Idea 5of 8Builds onA push or a pullHow much stuff
Earth pulls everything
How hard does Earth pull a two-kilogram book?
Today you'll discover
- how hard Earth pulls, per kilogram
- what changes on the Moon and what does not
- the unit a force is measured in
Think firstA 2 kg book. Take it to the Moon
The same book on the Moon. What changes?
Decide first, then press Next. Read the arrow against the scale bar.
A box with a dot at its centre on a heavy line, with one arrow pointing straight down from the centre. After a prediction the arrow's value is printed beside a short scale bar, then the box's mass is printed above it. The last step asks the weight of a ten-kilogram bag on the Moon.
See the whole ideathe big idea and the key word, in one place
The big idea
Weight is Earth's pull: mass times 9.8 N per kilogram.
Compare themMass: how much stuff, in kilograms, the same everywhere. Weight: how hard the planet pulls it, in newtons, different on each world.
Key words
- weight
- the force of gravity on an object: Fg = m g, in newtons, pointing down
- newton
- the unit of force, symbol N; about the weight of a small apple
About this modelArrows are forces, not motion: a box can move with no arrow pointing its way.
Arrows are forces, not motion: a box can move with no arrow pointing its way.
Ready to use it?
- Find the weight of a given mass on Earth, on the Moon and on Mars.