Free GCSE Physics lesson: Ripple Tank Practical
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Free Lessons -> GCSE / Key Stage 4 -> Physics -> Ripple Tank Practical

Lesson 22 · GCSE / Key Stage 4 · Physics

Practical method: waves in a ripple tank

Measure wave speed using frequency and wavelength in a ripple tank or stretched string setup.

Qualification: GCSE Subject: Physics Practical method

Practical skills

Lesson overview

This lesson introduces the core physics idea, the useful equipment and the calculation or data skills used on this page.

FocusWave speed practical method and uncertainty
Time45-60 minutes
EquipmentRipple tank or vibration generator, ruler, timer or frequency source and lamp if available.
Practical linkRequired/core practical focus
Maths tagsM1 substitution with units, M6 ratio and percentage

What you will learn

  • Describe how to measure wavelength in a ripple tank.
  • Use wave speed = frequency x wavelength.
  • Explain how to reduce percentage uncertainty in wavelength measurement.
  • Identify safety and setup issues for wave practicals.

Wave practical data supplied on this page

Use the ripple spacing and frequency data to practise wave speed calculations and method improvements.

Ripple tank wave speed practical infographic

Infographic explaining the GCSE Physics ripple tank wave speed practical, including ripple tank apparatus, wavefront spacing, wavelength measurement, wave speed equals frequency times wavelength, variables, a graph cue and exam checks.
Use this visual to set up the ripple tank practical, measure wavelength accurately and connect frequency, wavelength and wave speed.Download visual

Clear explanation

In a ripple tank, waves can be made by a vibrating dipper. The distance between wavefronts gives wavelength.

Measuring several wavelengths together and dividing by the number of waves reduces percentage uncertainty compared with measuring one wavelength.

If frequency is known, wave speed can be calculated using wave speed = frequency x wavelength.

Key diagram

Ripple tank wavefront spacing for wavelength Parallel wavefronts pass through a ripple tank with wavelength measured between neighbouring crests and a lamp-screen arrangement implied. wavelength wavefronts seen on the screen below
Diagram: the labelled crest spacing supports the wave speed practical method: wave speed equals frequency times wavelength.

Worked examples

Measuring several wavelengths

Five wavelengths measure 20 cm across the screen.

One wavelength = 20 ÷ 5 = 4 cm = 0.04 m.

Frequency = 12 Hz, so speed = 12 x 0.04 = 0.48

Answer: The wave speed is 0.48 m/s.

Quick checks

Choose an answer, then check your thinking.

1. Why measure several wavelengths instead of one?

2. Which equation gives wave speed?

Practice questions

Question 1

Four wavelengths measure 16 cm. Calculate one wavelength in metres.

Reveal answer and marking guidance

Answer: 0.04 m.

Marking: Credit 16 ÷ 4 = 4 cm = 0.04 m.

Question 2

A wave has frequency 8 Hz and wavelength 0.05 m. Calculate speed.

Reveal answer and marking guidance

Answer: 0.4 m/s.

Marking: Credit v = f lambda = 8 x 0.05 = 0.4 m/s.

Question 3

Name one control variable in a ripple tank wave-speed practical.

Reveal answer and marking guidance

Answer: Water depth.

Marking: Credit water depth, frequency setting or same measurement setup.

Question 4

Why might a lamp and screen help in a ripple tank?

Reveal answer and marking guidance

Answer: They make wavefronts easier to see and measure.

Marking: Credit clearer observation and measurement.

Practice ladder

FluencyRecall the key definition, unit, equation or model before using the lesson questions.
ApplicationApply wave speed practical method and uncertainty to an unfamiliar device, practical setup or data description.
Practical interpretationUse evidence, graph features, uncertainty, method quality or conclusion wording where the question asks you to evaluate.
Maths skillM1 substitution with units

Answers and marking guidance

The exact practice answers are hidden under each question so you can try first. For this lesson, marks come from using the correct physics model, choosing the right equation where needed, keeping units with values, and explaining changes with precise words such as transfer, resultant force, acceleration, evidence and uncertainty.

Common mistakes

  • Forgetting to convert cm to m.
  • Measuring from crest to trough instead of matching points.
  • Changing water depth without noting it.
  • Using frequency divided by wavelength for speed.

Extension challenge

Plan how to compare wave speed in shallow and deeper water while keeping the method fair.

Reveal answer

Example answer: A strong extension response names the physics model, uses accurate units and explains why the evidence supports the conclusion.

Exam-board guidance

Short board notes only. Learn the core physics above first.

AQA GCSE Physics

AQA GCSE Physics: often rewards clear physics explanations, correct equations, units and practical evidence for wave speed practical method and uncertainty.

OCR GCSE Physics

OCR GCSE Physics: often values precise definitions, clear working, graph interpretation and links between models and evidence.

Pearson Edexcel GCSE Physics

Pearson Edexcel GCSE Physics: often combines the concept with equation use, data handling and practical interpretation.

Eduqas GCSE Physics

Eduqas GCSE Physics: learn the core explanation and practise applying it to unfamiliar contexts, data and practical questions.

WJEC Wales

WJEC Wales: often expects accurate terms, units and evidence-based explanations using the shared physics idea.

CCEA GCSE Physics

CCEA GCSE Physics: connect the idea to your current unit and use the same practical method language your class uses.

Next lesson

Next, continue with Domestic Electricity and Safety.

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