4-PS4-1: Modeling Waves
Also called NGSS 4-PS4-1 · Topic: Waves · Physical Science
The Official Wording
Develop a model of waves to describe patterns in terms of amplitude and wavelength and that waves can cause objects to move.
Clarification statement: Examples of models could include diagrams, analogies, and physical models using wire to illustrate wavelength and amplitude of waves.
Assessment boundary: Assessment does not include interference effects, electromagnetic waves, non-periodic waves, or quantitative models of amplitude and wavelength.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 4-PS4-1 Means in Plain English
Fourth graders build models of waves, such as drawings or a shaking rope, to describe their patterns. They learn two words: amplitude, how tall a wave is from its middle line, and wavelength, the distance from one crest to the next. They also see waves move things.
The waves stay simple and regular, like ripples on water or a wiggling rope. Light waves, overlapping waves and wave math wait until middle school (MS-PS4-1). Sound as vibration from 1-PS4-1 is a good starting point.
4-PS4-1 I Can Statements
- I can point to the amplitude and wavelength of a wave.
- I can make a model that shows a wave pattern.
- I can show that a wave can push an object.
4-PS4-1 Worked Example
A wave model a class can make on the gym floor with one long jump rope and a foam block.
How does the way we shake a rope change its waves, and can the waves move something?
Set It Up: A long jump rope with one end tied to a chair leg, a strip of tape marking the rope's resting line, and a small foam block.
- Shake the free end gently side to side, slowly.Low waves, crests far apart
- Swing your arm wider at the same slow pace.Taller waves, same spacing: more amplitude
- Make small swings, but much faster.Crests bunch closer: shorter wavelength
- Sketch each pattern and label a crest, the amplitude and the wavelength.Three labeled drawings
- Set the foam block against the rope near the chair and send big waves.The block slides when a crest reaches it
Wider swings made taller waves, faster shaking packed the crests closer, and big waves pushed the block.
Why it works: A wave carries energy along the rope, so it can move objects it reaches, and a taller wave carries more energy.
Common Mistakes with 4-PS4-1
Mixing up amplitude and wavelength
Measuring from crest to crest and calling it amplitude
Try this: Amplitude goes up and down, from the middle line to a crest. Wavelength goes along, from one crest to the next crest.
Thinking the water travels with the wave
“The wave carried the water across the pool.”
Try this: Watch a floating leaf on a ripple. It bobs up and down in place while the wave moves past, so energy travels, not the water.
Thinking faster shaking makes taller waves
“I shook faster, so the waves got taller.”
Try this: Shaking faster changes the spacing, so crests get closer. To make taller waves, swing your arm farther side to side instead.
Where 4-PS4-1 Fits
Practice 4-PS4-1
Quick Check
- What is the amplitude of a wave?
- You shake a rope faster. What happens to the wavelength?
- How can you tell a wave carries energy?