Water waves
I can explain how water waves consist of oscillations of water and describe how water waves can superpose and reflect.
Water waves
I can explain how water waves consist of oscillations of water and describe how water waves can superpose and reflect.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- As a water wave moves forward, each bit of water is moving up and down (oscillating), not forward.
- Water waves are transverse waves: the direction of oscillation is 90° to the direction of energy transfer.
- The amplitude of a water wave is the greatest distance water moves above and below the rest position.
- Waves that pass through each other can ‘add up’ or ‘cancel out’; this is called wave superposition.
- Water waves reflect from hard barriers, obeying the laws of reflection.
Keywords
Oscillation - back–and–forth movement
Transverse - describes a wave where the direction of oscillation is 90° to the direction of energy transfer
Amplitude - the greatest distance a material moves from the rest position when a wave passes through that material
Wave superposition - the process of waves ‘adding up’ or ‘cancelling out’ as they pass through each other
Wavefront - lines drawn to represent the positions of the peaks of a wave
Common misconception
Water moves forwards with a water wave.
Show pupils animations depicting how transverse waves are created in water (and on ropes) by patterns of oscillation. Explicitly draw their attention to how the wave shape / wave pattern travels forwards without any material travelling forwards.
To help you plan your year 9 science lesson on: Water waves, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 9 science lesson on: Water waves, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 3 science lessons from the Waves unit, dive into the full secondary science curriculum, or learn more about lesson planning.
Equipment
Teachers could consider using a ripple tank to demonstrate the reflection of water waves, to further enrich this lesson.
Licence
Lesson video
Starter quiz
6 Questions
line showing where two different types of material meet
arrow showing the direction of a wave after reflection
arrow showing the direction of the wave as it approaches a mirror
imaginary line at right angles to a mirror at the point a ray meets it
Exit quiz
6 Questions
rest position
peak
amplitude
trough
