# A submarine dives from the surface of the ocean to a much greater depth. Explain why the pressure acting on the outside of the submarine increases as it dives deeper.

> OCR GCSE Physics A: Gateway Science (J249) — P1.3 Pressure · Explain · 4 marks

> Submarines are designed to withstand very large pressures when operating at depth. Engineers must account for how pressure changes with depth when designing the hull.

## Mark scheme (4 marks)

1. Pressure in a liquid increases with depth / greater depth means greater pressure
2. There is a greater height (column) of water above the submarine at greater depth
3. This greater column of water has a greater weight
4. This greater weight acts over the same unit area, so the pressure (force per unit area) is greater

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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-submarine-dives-from-the-surface-25a34385) · Published by Druglandscape Ltd.