# A student notices that a label on a bottle of shampoo gives its volume in millilitres but does not state the mass of the shampoo inside. The student says: 'Volume and mass are both scalar quantities, so they are basically the same type of measurement.' Explain why the student's statement is incorrect, and describe the difference between a scalar quantity and a vector quantity.

> OCR A-Level Physics B: Advancing Physics (H557) — 2.1 Physical quantities and units · Explain · 5 marks

> A student is reading labels on bottles in a supermarket and makes a comment about physical quantities printed on the packaging.

## Mark scheme (5 marks)

1. A scalar quantity has magnitude only (no direction)
2. A vector quantity has both magnitude and direction
3. The student is correct that both mass and volume are scalar quantities / both have no direction
4. Mass and volume measure different physical quantities / mass measures the amount of matter whereas volume measures the space an object occupies
5. Being the same type (scalar) does not mean they are the same quantity / scalar vs vector classification does not determine what physical property is measured

## Key terms

- [scalar quantity](https://www.gradenine.co.uk/glossary/scalar-quantity)
- [vector quantity](https://www.gradenine.co.uk/glossary/vector-quantity)
- [mass](https://www.gradenine.co.uk/glossary/mass)

## Related

- [Revision notes for OCR A-Level Physics B: Advancing Physics (H557)](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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-notices-that-a-label-7d05b73d) · Published by Druglandscape Ltd.