1-PS4-3: Shining Light on Materials
Also called NGSS 1-PS4-3 · Topic: Waves: Light and Sound · Physical Science
The Official Wording
Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light.
Clarification statement: Examples of materials could include those that are transparent (such as clear plastic), translucent (such as wax paper), opaque (such as cardboard), and reflective (such as a mirror).
Assessment boundary: Assessment does not include the speed of light.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 1-PS4-3 Means in Plain English
First graders shine a flashlight at different materials and watch what happens to the beam. Clear plastic lets almost all the light through, tissue paper lets some through, cardboard blocks it and leaves a shadow, and a mirror bounces it somewhere new.
Children sort materials by what they see, using words like transparent, translucent, opaque and reflective. How fast light travels is not part of this standard. It builds on 1-PS4-2 (we see only with light) and leads to 4-PS4-2, where light entering the eye explains sight.
1-PS4-3 I Can Statements
- I can test what light does when it hits different materials.
- I can sort materials into see-through, partly see-through and blocking.
- I can show how a mirror changes the path of light.
1-PS4-3 Worked Example
A beam test a class can run in a dimmed room with one flashlight and a poster board screen.
What happens to a flashlight beam when different materials are put in its way?
Set It Up: A flashlight, a white poster board taped to the wall as a screen, a clear sheet protector, tissue paper, a piece of cardboard and a small mirror.
- Dim the lights and shine the flashlight at the poster board from about a meter away.Bright circle on the board
- Hold the clear sheet protector in the beam.Circle stays bright
- Swap in the tissue paper.Circle turns dim and fuzzy
- Swap in the cardboard.Circle disappears, a shadow takes its place
- Hold the mirror in the beam and tilt it slowly.A bright spot jumps to the ceiling or another wall
- Sort the materials on a chart: lets light through, lets some through, blocks it, bounces it.Four groups
The clear plastic let the light through, tissue paper let some through, cardboard blocked it, and the mirror sent it in a new direction.
Why it works: Materials treat light differently: some let it pass, some scatter part of it, some stop it, and smooth shiny surfaces reflect it.
Common Mistakes with 1-PS4-3
Thinking a shadow is a thing
“The cardboard makes a dark shadow come out of it.”
Try this: A shadow is the spot where light could not reach. Move the cardboard away and the light lands on that spot again.
Treating cloudy like clear
Tissue paper sorted with the clear plastic because “some light gets through”
Try this: Compare the circle on the screen each time. A dim, fuzzy circle means only some light passed, so it gets its own group.
Thinking the mirror blocks light
“The mirror is like the cardboard. The light is gone.”
Try this: Look around the room, not just at the screen. The light bounced off the mirror and landed somewhere else, so it was not stopped.
Where 1-PS4-3 Fits
Practice 1-PS4-3
Quick Check
- You hold cardboard in front of a flashlight. What happens on the wall?
- Which lets more light through, a clear plastic bag or a paper bag?
- What does a mirror do to a beam of light?