Science lesson plan · 4th grade (Year 5 in England) · 60 minutes
Measure and compare waves: amplitude and wavelength
Light, sound and waves
CCSS NGSS.4-PS4-1England: KS3 Physics: Waves (observed waves)
Objective and success criteria
Students will: Measure and compare waves: amplitude and wavelength.
- 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: crest, trough, amplitude and wavelength
Leads to: the next skill in this area.
Materials: Slinky or rope, Mirrors and torches, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (Parts of a wave: crest, trough, amplitude and wavelength). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- True or false? Amplitude is the distance from crest to crest. (True / False) → FalsePrompt: Two are points (top and bottom); two are distances (across and up).
- True or false? The trough is the highest point of a wave. (True / False) → FalsePrompt: Two are points (top and bottom); two are distances (across and up).
- True or false? The crest is the top of a wave. (True / False) → TruePrompt: Two are points (top and bottom); two are distances (across and up).
Hook · 6 min
- Ask the class to make a wave with a rope or slinky and describe what moves and what doesn't.
- Share the objective: Measure and compare waves: amplitude and wavelength. Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: In a long spring (slinky) on the floor, 5 complete waves fit into 45 cm. What is the wavelength?
- Step 1: 45 ÷ 5 = 9
- Step 2: So the answer is: 9 cm
- Answer: 9 cm
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- In waves on a pond, 2 complete waves fit into 4 cm. What is the wavelength? → 2 cmPrompt: Wavelength is the length of one complete wave.
- Two sound waves are drawn the same way. Wave A has an amplitude of 4 squares and wave B has 2 squares. Which is the LOUDER sound? (wave A / wave B) → wave APrompt: Bigger amplitude means more energy.
You do: independent practice · 17 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Two sound waves are drawn the same way. Wave A has an amplitude of 3 squares and wave B has 6 squares. Which is the LOUDER sound? (wave A / wave B) → wave BPrompt: Bigger amplitude means more energy.
- In a skipping rope being shaken, 4 complete waves fit into 36 cm. What is the wavelength? → 9 cmPrompt: Wavelength is the length of one complete wave.
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: crest, trough, amplitude and wavelength.
- 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
- 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-4.
Free lesson plan from eurekami.com/lesson-plan-builder