Waves
Lesson overview
This lesson introduces the core physics idea, the useful equipment and the calculation or data skills used on this page.
What you will learn
Wave examples supplied on this page
Use the ripple tank, sound wave and electromagnetic spectrum prompts to practise naming wave quantities and choosing the wave equation.
Waves, light and electromagnetic spectrum infographic
Clear explanation
A wave transfers energy and information without transferring matter overall. Water waves, sound waves and electromagnetic waves behave differently, but the same wave vocabulary helps describe them.
Wavelength is the distance from one point on a wave to the matching point on the next wave. Frequency is the number of waves each second.
Electromagnetic waves are transverse and can travel through a vacuum. They include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.
Key diagram
Worked examples
Calculating wave speed
A wave has frequency 5 Hz and wavelength 0.8 m.
wave speed = frequency x wavelength
wave speed = 5 x 0.8 = 4
Quick checks
Choose an answer, then check your thinking.
1. A wave has frequency 10 Hz and wavelength 2 m. What is its speed?
2. Which electromagnetic wave has a higher frequency than visible light?
Practice questions
Question 1
A water wave travels at 3 m/s and has wavelength 0.5 m. Calculate the frequency.
Reveal answer and marking guidance
Answer: 6 Hz.
Marking: Credit frequency = wave speed ÷ wavelength and 3 ÷ 0.5 = 6 Hz.
Question 2
State one difference between transverse and longitudinal waves.
Reveal answer and marking guidance
Answer: In transverse waves, oscillations are perpendicular to the direction of travel; in longitudinal waves, oscillations are parallel.
Marking: Credit a clear comparison of oscillation direction.
Question 3
Why can light from the Sun reach Earth through space?
Reveal answer and marking guidance
Answer: Light is an electromagnetic wave and can travel through a vacuum.
Marking: Credit electromagnetic wave and vacuum.
Question 4
Name one electromagnetic radiation that can ionise atoms and needs careful medical use.
Reveal answer and marking guidance
Answer: X-rays or gamma rays.
Marking: Credit X-rays or gamma rays, with a sensible safety reason.
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
- Confusing amplitude with wavelength.
- Using period instead of frequency in the wave speed equation.
- Saying sound can travel through a vacuum.
- Thinking all radiation is nuclear radiation.
Extension challenge
Create a spectrum card sort from radio waves to gamma rays, then add one use and one hazard where relevant.
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 properties and electromagnetic radiation.
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 Atomic Structure and Radioactivity.