GCSE · Physics · AQA · Spec 8463

Transverse and longitudinal waves

Every sound you hear, every light you see — all carried by waves.

What you need to know

  • Transverse waves: oscillations are perpendicular to the direction of energy transfer (e.g. light, water ripples).
  • Longitudinal waves: oscillations are parallel to the direction of energy transfer, with compressions and rarefactions (e.g. sound).
  • Waves transfer energy and information — the medium itself does not travel with the wave.
  • Key quantities: amplitude (max displacement from rest), wavelength (one complete cycle length), frequency (cycles per second), period (time for one cycle); linked by v = f λ and T = 1 / f.

The big picture

Waves transfer energy and information from place to place without transferring matter — the medium stays put while the disturbance travels through it. Transverse waves oscillate perpendicular to the direction of energy transfer, such as light and water ripples. Longitudinal waves oscillate parallel to the direction of energy transfer, creating alternating compressions and rarefactions — sound is the classic example. Four key quantities describe any wave: amplitude, wavelength, frequency and period, linked by v = f λ and T = 1 / f.

TONIGHT'S REVISION

Transverse and Longitudinal Waves

How waves move energy — and why the medium never travels with them

Physics · Wave properties

Wave Properties Explorer

Adjust the sliders and watch how amplitude, frequency and wavelength interact

amplitudewavelength λ

Amplitude

10cm

Wavelength λ

2.00m

Frequency f

2Hz

Speed v = fλ

4m/s

Amplitude10 cm
Frequency2 Hz

The wave equation, live

2 Hz × 2.00 m = 4 m/s

Drag amplitude — the wave grows taller, but its speed and wavelength don't change. Drag frequency — the peaks crowd together, wavelength shrinks, and v = fλ keeps the books balanced. Period T = 0.5 s.

Exam line: Use v = f λ to link speed, frequency and wavelength — if speed is constant, higher frequency means shorter wavelength.
Watch out: Increasing amplitude does NOT change the wave speed or frequency — amplitude and frequency are independent quantities.

Stop and think

Picture a Mexican wave in a stadium, then picture sound travelling from a speaker to your ear — which is which?

A student says: 'In a longitudinal wave, the particles travel from the source to your ear — that's how sound reaches you.' What is wrong with this statement?

How a longitudinal wave travels

Follow one compression from where it starts to where it ends up

Waves and energy transfer

?

Reason it through

Why can a wave carry energy from one place to another without matter travelling with it?

Link 1 of 3

First link · your turn

What does each particle in the medium actually do when a wave passes?

2
Locked — reveal the link above first
3
Locked — reveal the link above first

Relationship matrix

Tap any cell to reveal it. Tap a column header to read one property down every item.

Direction of oscillationKey wave featuresDoes matter transfer?GCSE example
Transverse wavee.g. light, water ripples
Longitudinal wavee.g. sound

Each cell hides a short answer and the reason behind it. Predict before you tap.

Cross-subject · Exam skill

Command Word Coach — Waves on AQA

Know exactly what AQA Paper 2 is asking before you write a word

StateBloom · Knowledge

01Definition

Give a concise factual answer — no explanation needed.

02Mark-band signal

1-mark retrieval — one clear sentence scores full marks

03Sentence stems

  • State one difference between a transverse and a longitudinal wave.
  • State the equation linking wave speed, frequency and wavelength.
  • State what is meant by the amplitude of a wave.

04Common mistake

Students over-explain and then contradict themselves — keep it to one crisp sentence naming the direction of oscillation relative to energy transfer.

Exam line: On AQA Paper 2, 'state' = one line, 'describe' = name the features, 'explain' = feature + reason, 'calculate' = equation + substitution + unit. Match your answer length to the command word.
Watch out: A 'describe' answer that accidentally gives a reason is not penalised — but an 'explain' answer that only describes WILL lose marks.

Equations you need

Taken directly from the exam-board specification.

v = f λ

v = wave speed (m/s) · f = frequency (Hz) · λ = wavelength (m)

Learn it — you must recall this in the exam

T = 1 / f

T = period (s) · f = frequency (Hz)

Given on the equation sheet — you must know how to use it

Key points

1Transverse: oscillation is AT RIGHT ANGLES to the direction of travel — think a Mexican wave in a stadium.
2Longitudinal: oscillation is ALONG the same line as travel — compressions are squashed regions, rarefactions are stretched regions.
3Waves carry energy, NOT matter — a floating duck bobs up and down but does not travel with the ripples.
4Amplitude is the maximum displacement from the UNDISTURBED (rest) position, not peak to trough.
5v = f λ and T = 1 / f are your two key equations — know which is on the equation sheet (T = 1/f is given; v = fλ must be recalled).

Worked example

Problem

A wave in a ripple tank has a frequency of 4 Hz and a wavelength of 0.05 m. Calculate the wave speed.

🧠

Memory hook

TRANSVERSE = T-Rex arms — the oscillation sticks OUT sideways from the direction you're walking. LONGITUDINAL = along — the oscillation goes the same way as the wave.

★ Exam tip

AQA Paper 2 often asks you to 'state one difference between transverse and longitudinal waves' — always name the direction of oscillation RELATIVE to the direction of energy transfer, not just 'up and down vs back and forth'. Using the phrase 'perpendicular' and 'parallel' earns the mark.

⚠ Watch out

A common slip is to read amplitude as the FULL peak-to-trough distance. Amplitude is HALF the peak-to-trough distance — the displacement from the undisturbed rest position to a peak (or trough).

✓

Check yourself

Without looking — in a longitudinal wave, what is the name given to a region where particles are pushed close together, and what is the name for a region where they are spread apart?

Flashcards

(25)
What is a transverse wave?
A wave where the oscillations are perpendicular (at right angles) to the direction of energy transfer.
What is a longitudinal wave?
A wave where the oscillations are parallel to the direction of energy transfer.
Give two examples of transverse waves.
Any two from: electromagnetic waves (light, radio, UV, etc.), water ripples, waves on a string.
Give one example of a longitudinal wave.
Sound waves.
What is a compression in a longitudinal wave?
A region where particles are pushed close together — higher pressure region.
What is a rarefaction in a longitudinal wave?
A region where particles are spread further apart — lower pressure region.
Define amplitude.
The maximum displacement of a point on the wave from its undisturbed (rest) position.
Define wavelength.
The distance from one point on a wave to the equivalent point on the next cycle (e.g. crest to crest), measured in metres.
Define frequency.
The number of complete wave cycles passing a point per second, measured in hertz (Hz).
Define the period of a wave.
The time taken for one complete wave cycle to pass a point, measured in seconds.
State the wave speed equation.
v = f λ
State the equation linking period and frequency.
T = 1 / f
Is T = 1 / f given on the AQA physics equation sheet?
Yes — T = 1/f is provided. You must still be able to apply it.
Is v = f λ given on the AQA physics equation sheet?
No — you must recall v = f λ from memory.
A wave has a frequency of 50 Hz. What is its period?
T = 1/50 = 0.02 s
A wave has a wavelength of 2 m and frequency 150 Hz. What is its speed?
Using v = f λ: v = 150 × 2 = 300 m/s
Do waves transfer matter?
No — waves transfer energy and information. The medium oscillates but does not travel with the wave.
In a transverse wave, which direction do the particles oscillate?
Perpendicular (at right angles) to the direction of energy transfer.
In a longitudinal wave, which direction do the particles oscillate?
Parallel to (along the same line as) the direction of energy transfer.
What does RP8 (the waves required practical) measure?
The frequency, wavelength and speed of waves in a ripple tank and in a solid.
A wave has a period of 0.004 s. What is its frequency?
f = 1/T = 1/0.004 = 250 Hz
What is the unit of wave speed?
Metres per second (m/s)
What is the unit of frequency?
Hertz (Hz)
What is the unit of wavelength?
Metres (m)
What is the unit of period?
Seconds (s)

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

Learn Transverse and longitudinal waves properly — interactive practice, marked questions and flashcards.

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How this lesson was checked. This AQA GCSE Physics (specification 8463)lesson was published through Lightbulb Learning's human-designed editorial process — the educational standards, accuracy rules and publication checks it must pass were authored and approved by Philip Halpin. It passed subject-specific assessment, automated educational checks and technical publication verification before going live (publication checks completed 3 August 2026). Published pages are monitored, human spot-checking is ongoing across the lesson library, and anything found wrong is corrected or withdrawn. How our lessons are made and checked. Spotted a mistake? Email hello@lightbulblearning.co and we'll review it.

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