Tall Waves and Close Waves
A 55-minute Grade 4 lesson on modelling waves in terms of amplitude and wavelength, and showing that waves can move objects.
Tall Waves and Close Waves is a free 55-minute Grade 4 science lesson plan for Common Core standard 4-PS4-1 — model waves using amplitude and wavelength, and show they can move things. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Grade 4
- Length:
- 55 minutes
- Standard:
- 4-PS4-1
Grade 4 · Physical Science
4-PS4-1
Develop a model of waves to describe patterns in terms of amplitude and wavelength and that waves can cause objects to move.
Objective
Students will be able to change a wave's amplitude and wavelength and describe what each does.
Students are successful when they can
- Changes wave height and describes the effect on a float.
- Changes wave spacing and describes it.
- Says that the float bobs rather than travels.
What you need
- A shallow tank or tray of water, a paddle, a small float
- A rope for a large-scale wave demonstration
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up
5 min- Send one wave down a stretched rope and ask what moved along it.
- Ask whether the rope itself travelled.
Teach — two things you can change
14 min- Dip the paddle gently: low waves. The float bobs a little.
- Dip it hard: tall waves. The float bobs a lot. Name that height: amplitude.
- Paddle slowly: waves far apart. Paddle fast: waves close. Name that spacing: wavelength.
- Ask which of the two changed how much the float moved. The amplitude.
- Watch the float carefully: it goes up and down and stays put.
- Say what a model is for: it lets you change one thing and watch.
“Taller, or closer together? They are different changes.”
Investigate — change one at a time
19 min- Groups make low and tall waves and record the float's movement each time.
- They then make far-apart and close-together waves at the same height.
- They record which change altered the float's bobbing.
- They draw both wave patterns and label amplitude and wavelength.
Independent practice
14 min- Students complete the 'Tall Waves and Close Waves' page.
- Check amplitude and wavelength are not swapped.
Close
3 min- Ask why a boat rises and falls but does not get carried out to sea by every wave.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Thinks the water travels along with the wave.
Why: The wave clearly moves.
Fix: Watch the float. It bobs in one place while the wave passes.
Confuses amplitude with wavelength.
Why: Both describe the wave.
Fix: Amplitude is how tall. Wavelength is how far apart. Label a drawing.
Changes paddle height and speed together.
Why: Both make waves.
Fix: Then you cannot say which changed the float. One at a time.
If they are not there yet
- Two wave patterns to compare rather than four.
- A labelled diagram to copy.
If they finish early
- Find the smallest wave that still moves the float.
- Say what happens when two waves meet.
- Explain why a big storm wave damages more than a small one.
Exit ticket
A bigger paddle dip makes the float bob much more. Which property changed, and what does that show?
What to look for: The amplitude, showing taller waves move objects more. Naming wavelength means the two properties need another run.
Printable practice for 4-PS4-1
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Tall Waves and Close WavesCircle the best answer.
Questions about Tall Waves and Close Waves
How long does the Tall Waves and Close Waves lesson take?
55 minutes, split across 5 timed sections: warm-up 5 min, teach 14 min, investigate 19 min, independent practice 14 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does Tall Waves and Close Waves teach?
4-PS4-1 — 4-PS4-1, Physical Science for Grade 4: “Develop a model of waves to describe patterns in terms of amplitude and wavelength and that waves can cause objects to move.” In plain terms, model waves using amplitude and wavelength, and show they can move things.
What do I need to teach this lesson?
A shallow tank or tray of water, a paddle, a small float, a rope for a large-scale wave demonstration and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: thinks the water travels along with the wave; confuses amplitude with wavelength and changes paddle height and speed together. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “A bigger paddle dip makes the float bob much more. Which property changed, and what does that show?.” The amplitude, showing taller waves move objects more. Naming wavelength means the two properties need another run. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with Tall Waves and Close Waves?
Yes — 1 printable 4-PS4-1 worksheet, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is Tall Waves and Close Waves free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 8 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-08. Aligned to 4-PS4-1 of the Next Generation Science Standards.