Cambridge Primary (1-6). Stage 3. Science. Workbook - Unit 5: Forces and magnets - Question 27

William investigates the question ‘Which surface has the most friction?’ He measures friction on different surfaces to find the answer. Here are his results.

| Surface | Friction (N) |
|---|---:|
| Wood | 10 |
| Carpet | 20 |
| Sand | 18 |

This is his conclusion: ‘The friction on the carpet was 20 N.’

Write a better conclusion.