Science lesson plan · 8th grade (Year 9 in England) · 30 minutes
Transverse and longitudinal waves
Light, sound and waves
CCSS NGSS.MS-PS4-1CCSS NGSS.HS-PS4-1England: KS3 Physics: WavesEngland: GCSE Combined Science: Waves
Objective and success criteria
Students will: Transverse and longitudinal waves.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Parts of a wave; How sound travels through solids, liquids and gases
Leads to: Seismic waves as evidence for Earth's layers
Materials: Slinky or rope, Mirrors and torches, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Parts of a wave; How sound travels through solids, liquids and gases). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- An alarm clock rings inside a jar. As the air is pumped out, the ringing gets quieter. Why? (Air makes sound quieter / Sound needs particles to travel through, and there are fewer left / The clock stops ringing / Glass absorbs all sound) → Sound needs particles to travel through, and there are fewer leftPrompt: Can sound travel through a vacuum?
- 20 waves pass a point in 4 seconds. What is the frequency, in hertz (Hz)? → 5 HzPrompt: Frequency is the number of waves per second.
- Why does sound travel faster in steel than in air? (Sound is magnetic / Steel is shiny / Air has no particles / Particles in solids are close together and strongly linked, so vibrations pass on quickly) → Particles in solids are close together and strongly linked, so vibrations pass on quicklyPrompt: Think about how close particles are.
Hook · 3 min
- Ask the class to make a wave with a rope or slinky and describe what moves and what doesn't.
- Share the objective: Transverse and longitudinal waves. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Is this a transverse or a longitudinal wave: seismic P waves?
- Step 1: In longitudinal waves, vibrations are parallel to the direction the wave travels.
- Step 2: So the answer is: longitudinal
- Answer: longitudinal
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Is this a transverse or a longitudinal wave: light? (transverse / longitudinal) → transversePrompt: Compare the direction of vibration with the direction the wave travels.
- Which kind of wave can travel through a vacuum? (water waves / seismic waves / electromagnetic waves such as light / sound waves) → electromagnetic waves such as lightPrompt: Sunlight crosses space to reach us.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A cork floats on a pond as ripples pass. What does the cork do? (spins in a circle quickly / bobs up and down but does not travel with the wave / moves along with the wave to the edge / sinks) → bobs up and down but does not travel with the wavePrompt: Waves transfer energy, not matter.
- Types of wave: which statement is NOT true? (All electromagnetic waves are transverse. / Seismic P waves are longitudinal and S waves are transverse. / Waves transfer energy without transferring matter. / Light is a longitudinal wave.) → Light is a longitudinal wave.Prompt: Which kind of wave is light?
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Parts of a wave.
- Use concrete materials: slinky or rope.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Seismic waves as evidence for Earth's layers.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-8.
Free lesson plan from eurekami.com/lesson-plan-builder