Explain how a student could estimate the thickness of a single sheet of paper using only a ruler, giving a value you would expect.

AQA A-Level Physics (7408) — 3.1.3 Estimation of Physical Quantities · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (5 marks)

A single sheet is too thin to measure accurately with a ruler.

A student can stack a large number of sheets, e.g. 100 sheets, to form a pile.

The student measures the total thickness of the pile with the ruler.

The thickness of one sheet is then found by dividing the total thickness by the number of sheets.

A sensible expected value is about 0.1 mm (≈1×10⁻⁴ m).

Examiner tips

  • Use the command word ‘explain’ – describe the procedure, not just state it.
  • Show the calculation: total thickness ÷ number of sheets.
  • Give a realistic value within the given range.

Mark scheme (5 marks)

  1. Cannot measure one sheet directly / a single sheet is too thin to measure accurately with a ruler
  2. Stack / pile a large number of sheets together (e.g. 100 sheets)
  3. Measure the total thickness of the stack with the ruler
  4. Divide the total thickness by the number of sheets
  5. States a sensible expected value in the range 0.05 mm to 0.15 mm (or equivalent e.g. 5 × 10⁻⁵ m to 1.5 × 10⁻⁴ m)

Key terms in this question

thickness

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