Through, Dimly, or Not at All
A 50-minute Grade 1 lesson on testing what happens when different materials are put in the path of a beam of light.
Through, Dimly, or Not at All is a free 50-minute Grade 1 science lesson plan for Common Core standard 1-PS4-3 — test what different materials do to a beam of light. 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 1
- Length:
- 50 minutes
- Standard:
- 1-PS4-3
Grade 1 · Physical Science
1-PS4-3
Plan and conduct an investigation to determine the effect of placing objects made with different materials in the path of a beam of light.
Objective
Students will be able to test a material in a beam and sort it by how much light gets through.
Students are successful when they can
- Puts the material in the path of the beam.
- Sorts it into through, dimly, or not at all.
- Keeps the torch and distance the same each time.
What you need
- A torch per group, and a tray of materials: clear plastic, tissue, card, foil, tracing paper
- A white wall or screen to shine the beam onto
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up — guess three
5 min- Hold up clear plastic, tissue paper and thick card.
- Ask the class to predict what each will do to a beam.
Teach — three groups, one test
13 min- Shine the torch at the wall and note the bright patch.
- Put the clear plastic in the beam. The patch is still bright: light goes straight through.
- Put the tissue in. The patch is dim: only some light gets through.
- Put the card in. The patch is gone: no light gets through.
- Say what has to stay the same: the same torch, the same distance, the same room.
- Add the odd one out: hold up foil and ask where the light went. It bounced off.
“Put it in the way of the beam. What happened to the bright patch?”
Investigate — test the tray
17 min- Groups test every material in the tray, keeping the torch and distance fixed.
- They sort each into through, dimly, or not at all.
- They find one material that does none of the three, and say what it did instead.
- They order their 'dimly' pile from brightest to dimmest.
Independent practice
12 min- Students complete the 'Through, Dimly, or Not at All' page.
- Check that the sort is by light rather than by thickness alone.
Close
3 min- Ask which material the class would use to make a room dark.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Sorts by thickness rather than by light.
Why: Thick usually blocks more.
Fix: Test a thick clear block. Thick and see-through at once.
Thinks a shadow is something the material makes.
Why: The shadow appears with the material.
Fix: A shadow is where the light did not reach. The card stopped it.
Moves the torch between tests.
Why: It is easier to aim each time.
Fix: Mark the torch's place. If the distance changes, the results cannot be compared.
If they are not there yet
- Three materials, one per group.
- Two categories: light gets through or it does not.
If they finish early
- Find a material that bounces the light instead.
- Order five materials from most to least light.
- Design a cover that lets exactly a dim glow through.
Exit ticket
Thick card is put in the path of a torch beam. What happens, and why is there a shadow behind it?
What to look for: No light gets through, so no light reaches behind it. An answer about the card being dark means the blocking idea needs another run.
Printable practice for 1-PS4-3
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Through, Dimly, or Not at AllSort each material into what it does to light.
Questions about Through, Dimly, or Not at All
How long does the Through, Dimly, or Not at All lesson take?
50 minutes, split across 5 timed sections: warm-up 5 min, teach 13 min, investigate 17 min, independent practice 12 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 Through, Dimly, or Not at All teach?
1-PS4-3 — 1-PS4-3, Physical Science for Grade 1: “Plan and conduct an investigation to determine the effect of placing objects made with different materials in the path of a beam of light.” In plain terms, test what different materials do to a beam of light.
What do I need to teach this lesson?
A torch per group, and a tray of materials: clear plastic, tissue, card, foil, tracing paper, a white wall or screen to shine the beam onto 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: sorts by thickness rather than by light; thinks a shadow is something the material makes and moves the torch between tests. 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: “Thick card is put in the path of a torch beam. What happens, and why is there a shadow behind it?.” No light gets through, so no light reaches behind it. An answer about the card being dark means the blocking idea needs 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 Through, Dimly, or Not at All?
Yes — 1 printable 1-PS4-3 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 Through, Dimly, or Not at All 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 1-PS4-3 of the Next Generation Science Standards.