MS-PS4-2: Reflecting, Absorbing and Transmitting Waves
Also called NGSS MS-PS4-2 · Topic: Waves and Electromagnetic Radiation · Physical Science
The Official Wording
Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
Clarification statement: Emphasis is on both light and mechanical waves. Examples of models could include drawings, simulations, and written descriptions.
Assessment boundary: Assessment is limited to qualitative applications pertaining to light and mechanical waves.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-PS4-2 Means in Plain English
Students build models showing what happens when light or sound meets a material: the wave can bounce off, soak in, or pass through. They test materials such as glass, foam, tile and cloth, then explain why each one behaves differently.
The models stay descriptive, using light and mechanical waves like sound and water waves, with no equations. They build on seeing objects by reflected light (4-PS4-2) and lead to how absorbed radiation affects living tissue in HS-PS4-4.
MS-PS4-2 I Can Statements
- I can tell whether a material reflects, absorbs or transmits a wave.
- I can draw a model of a wave meeting a surface.
- I can explain why soft foam makes a room quieter.
MS-PS4-2 Worked Example
A sound test a class can run with two phones, a shoebox and a few panels of different materials.
Which materials reflect sound, which absorb it, and which let it through?
Set It Up: One phone playing a steady tone, a second phone running a sound meter app, a shoebox, two cardboard tubes, and panels of acoustic foam, ceramic tile, cardboard and a folded towel.
- Put the tone phone in the open shoebox and hold the meter 30 cm above it.Open box: 72 dB
- Cover the box with each panel in turn and read the meter.Cardboard 65, towel 63, foam 63, tile 58 dB
- Aim one tube at the tile at an angle, set the meter at the end of a second tube angled back the same way, and read it.Tile reflection: 64 dB
- Swap the tile for the foam and repeat.Foam reflection: 51 dB
- Sort each material by what it mostly does to the sound.Tile reflects, foam and towel absorb, cardboard lets the most through
Hard, smooth tile bounced sound back strongly and blocked the most, while soft foam and the towel soaked sound up instead of reflecting it.
Why it works: When a wave meets a material, its energy is split among reflection, absorption and transmission, and the material's hardness and texture decide the split.
Common Mistakes with MS-PS4-2
Thinking a wave does only one thing
“Glass lets light through, so it doesn't reflect any.”
Try this: Most materials do all three at once. Glass transmits most light but still reflects some, which is why you see faint reflections in windows.
Saying absorbed energy disappears
“The foam made the sound vanish.”
Try this: Absorbed wave energy is not destroyed. It becomes thermal energy in the material, warming it by a tiny amount.
Mixing up absorbing and blocking
“Tile absorbs the most sound because it blocked the most.”
Try this: Blocking can mean reflecting. Check the reflection test too: hard tile sends sound back, while soft foam soaks it up.
Where MS-PS4-2 Fits
Practice MS-PS4-2
Quick Check
- Why do recording studios cover their walls with soft foam?
- Sunlight hits a black T-shirt. What happens to most of the light?
- You see your face faintly in a shop window. What does that show?