Practical skills
This lesson builds wave speed practical method and uncertainty for GCSE Physics.
Use the core lesson first, then match the exam-board guidance to your school route. Many pupils meet this content through Combined Science as well as Separate Physics.
What you will learn
Exam-board fit
Exact paper labels and specification-point numbering vary by board and cohort, so match this lesson to your school route before using past-paper questions.
Wave practical data supplied on this page
Use the ripple spacing and frequency data to practise wave speed calculations and method improvements.
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
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
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.
Exam practice ladder
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.
Exam-board guidance
All supported routes assess the core physics idea, but they may group topics, practicals and paper wording differently.
AQA GCSE Physics
AQA GCSE Physics: use this lesson for wave speed practical method and uncertainty, then check whether your class is taking Separate Physics or Combined Science.
OCR GCSE Physics
OCR GCSE Physics: the core physics idea is shared, but Gateway and Twenty First Century may organise questions differently.
Pearson Edexcel GCSE Physics
Pearson Edexcel GCSE Physics: practise the concept, the equation use and the practical language because questions often connect them.
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: check whether your class is using the current GCSE Physics route or a newer science route, then use this lesson for the shared physics idea.
CCEA GCSE Physics
CCEA GCSE Physics: connect the idea to your unit and remember that practical skills are assessed directly.
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.
Next lesson
Next, continue with Domestic Electricity and Safety.