# Explain why a gas has a much lower density than a solid made from the same substance.

> Edexcel GCSE Physics (1PH0) — 14.1 Particle model · Explain · 4 marks

## Mark scheme (4 marks)

1. In a solid, particles are tightly packed together / very close together
2. In a gas, particles are spread far apart / the spacing between particles is much greater
3. The much greater spacing means the volume occupied by the same mass of gas is far larger
4. Since density is mass per unit volume, a larger volume for the same mass means a much lower density

## Key terms

- [density](https://www.gradenine.co.uk/glossary/density)
- [gas](https://www.gradenine.co.uk/glossary/gas)
- [solid](https://www.gradenine.co.uk/glossary/solid)

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-a-gas-has-a-c52e48d0) · Published by Druglandscape Ltd.