# Describe how you could use a plotting compass and a straight bar magnet to investigate the shape of the magnetic field around the magnet, and state what the direction of the compass needle tells you about the magnetic field.

> OCR GCSE Physics A: Gateway Science (J249) — P3.3 Magnetism and the motor effect · Describe · 4 marks

> A student is investigating magnetic fields using simple equipment available in a school laboratory.

## Mark scheme (4 marks)

1. Place the bar magnet on a flat surface and position the plotting compass near one end of the magnet
2. Mark the position of the compass needle (e.g. mark a dot at the tip/tail of the needle) and move the compass to the next position
3. Repeat to build up a series of points that can be joined to show the shape of the field lines / field pattern around the magnet
4. The compass needle points in the direction of the magnetic field at that point / from north pole to south pole, showing the direction of the field

## Key terms

- [magnetic field](https://www.gradenine.co.uk/glossary/magnetic-field)
- [plotting compass](https://www.gradenine.co.uk/glossary/plotting-compass)

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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/describe-how-you-could-use-a-1016ff2c) · Published by Druglandscape Ltd.