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NGSS*Middle SchoolPhysical Science

MS-PS4-1: Wave Amplitude and Energy

Also called NGSS MS-PS4-1 · Topic: Waves and Electromagnetic Radiation · Physical Science

Practice ItAll 59 Middle School Science Standards

The Official Wording

Use mathematical representations to describe a simple model for waves that includes how the amplitude of a wave is related to the energy in a wave.

Clarification statement: Emphasis is on describing waves with both qualitative and quantitative thinking.

Assessment boundary: Assessment does not include electromagnetic waves and is limited to standard repeating waves.

NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026

What MS-PS4-1 Means in Plain English

Students describe a simple repeating wave with numbers and drawings, labeling its amplitude, wavelength and frequency. They measure amplitude and show with data that waves with a bigger amplitude carry more energy, like ocean swells that hit a pier harder.

The work uses ordinary repeating waves such as water and spring waves, not light or other electromagnetic waves. It builds on wave patterns from 4-PS4-1 and leads to the math linking wave speed, frequency and wavelength in HS-PS4-1.

MS-PS4-1 I Can Statements

  • I can label amplitude and wavelength on a wave drawing.
  • I can explain why a bigger amplitude means more energy.
  • I can use measurements to compare two waves.

MS-PS4-1 Worked Example

A spring wave test a class can run on a long tabletop with a slinky and an empty juice box.

The Question

Does a wave with a bigger amplitude carry more energy?

Set It Up: A metal slinky stretched about 2 meters along a table, masking tape marks 10 cm and 20 cm to one side of its resting line, and an empty juice box touching the coils near the far end.

A slinky wave and a juice box
SlinkyJuice boxShake10 cm20 cm
What Students Do
  1. With a partner holding the far end still, shake the near end side to side so the coils reach the 10 cm mark.Amplitude 10 cm
  2. Measure how far the juice box slides when the waves sweep past it.Box slides 8 cm
  3. Reset the box and shake to the 20 cm mark at the same pace.Box slides 30 cm
  4. Run three tries of each and record the averages in a table.10 cm: 8 cm, 20 cm: 31 cm
  5. Compare the ratios in the table.2 times the amplitude, about 4 times the push
What They Find

Doubling the amplitude made the box slide about four times as far.

Why it works: A wave's energy grows with the square of its amplitude, so twice the amplitude carries about four times the energy.

Common Mistakes with MS-PS4-1

Mixing up amplitude and wavelength

Measuring from one crest to the next and calling it amplitude

Try this: Amplitude is the height from the resting line to a crest. The distance from crest to crest is the wavelength.

Measuring crest to trough

“The amplitude is 40 cm,” for a wave reaching 20 cm each side

Try this: Measure from the middle resting line to the top of a crest, which is half the total crest to trough height.

Thinking energy grows in step with amplitude

“Twice as tall means twice the energy.”

Try this: Energy grows faster than amplitude. Doubling the amplitude gives about four times the energy, because energy depends on amplitude squared.

Where MS-PS4-1 Fits

Comes Before4-PS4-1Model waves as repeating patterns of amplitude and wavelength that can move objects.
AlongsideMS-PS4-2Model how waves reflect, get absorbed or pass through different materials.7.RP.A.2Tell proportional from non-proportional relationships, like amplitude and wave energy.
Comes NextHS-PS4-1Use math to relate the frequency, wavelength and speed of waves in different materials.

Practice MS-PS4-1

Graph Paper GeneratorFree ToolPlot amplitude against how far the box slid and notice that the points curve upward instead of forming a straight line.Amplitude in cmSlide distanceScatter plot
Open
Flashcard MakerFree ToolMake cards for the wave words students need before they label and compare waves.AmplitudeWavelengthFrequency
Open

Quick Check

  1. Two waves have the same wavelength. One has an amplitude of 3 cm, the other 6 cm. Which carries more energy?
  2. On a wave drawing, where do you measure the amplitude?
  3. Why do big waves crash harder on a beach than small ones?

MS-PS4-1: Other Names

MS-PS4-1NGSS MS-PS4-1Wave amplitudeWaves and energy

Official wording from NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press. The plain-English lines and everything else on this page are EMStudio’s own explanations, written beside the official wording. They are not part of the standards.

*NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.