# A space probe travels from Earth to Mars. Explain why the weight of the probe changes during the journey, whilst its mass remains the same.

> Cambridge International IGCSE Physics (0625) — 1.3 Mass and weight · Explain · 4 marks

## Mark scheme (4 marks)

1. Mass is a measure of how much matter is in an object / mass does not depend on location
2. Weight is the gravitational force acting on the probe / weight depends on gravitational field strength
3. Gravitational field strength varies between Earth, Mars, and deep space / g differs from planet to planet
4. Since weight = mass × gravitational field strength, a change in g causes a change in weight whilst mass stays constant

## Key terms

- [mass](https://www.gradenine.co.uk/glossary/mass)
- [weight](https://www.gradenine.co.uk/glossary/weight)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-space-probe-travels-from-earth-4a36e8bc) · Published by Druglandscape Ltd.