# A student wants to find the density of an irregularly shaped rock. Describe how the student should measure the volume of the rock and explain how errors in the experiment should be avoided.

> Pearson Edexcel International GCSE Physics (4PH1) — 5.1 Density and pressure · Describe · 4 marks

> The student has access to a measuring cylinder, water, a balance, and a piece of string.

## Mark scheme (4 marks)

1. Partially fill the measuring cylinder with water and record the initial volume reading
2. Immerse / submerge the rock fully in the water (using string) and record the new volume reading; the difference between the two readings is the volume of the rock
3. Read the volume from the measuring cylinder at eye level (straight-on) to avoid parallax error
4. Place the empty measuring cylinder on the balance and press tare (or record its mass and subtract) before adding liquid, to avoid zero error when measuring mass

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-wants-to-find-the-aa447323) · Published by Druglandscape Ltd.