You will learn
- Define opaque.
- Test materials.
- Sort into three groups.
- Choose materials for purposes.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- Opaque materials block light.
- We cannot see through them.
- Wood, metal and card are opaque.
- Opaque objects make dark shadows.
Words to know
not letting any light through
to take in light
to group by features
a feature of a material
1. Discover: The curtain test
Seyram closes a thick curtain in a bright room. The room gets dark. “The curtain does not let any light through,” she says. She tests foil, wood and cardboard with a torch. No light passes. “All opaque,” she writes.
Think: Why do bedrooms often have thick curtains?
2. Understand: Opaque
Idea 1: What is opaque?
Opaque materials do not let any light pass. They absorb or reflect all of it. Wood, metal, stone and thick card are opaque.
Idea 2: Sorting
We sort materials by shining a torch and noting whether light passes fully, partly or not at all. This property decides how we use them.
Idea 3: Shadows
Opaque objects make the darkest shadows because no light gets through. Translucent objects make faint shadows.
3. Worked examples
Example 1 (I show you): Test
Wood.
- No light.
- Dark behind.
- Opaque.
Answer: Wood is opaque.
Example 2 (We do it together): Sort
Tissue, foil, glass.
- Tissue translucent.
- Foil opaque.
- Glass transparent.
Answer: One of each group.
Example 3 (You try): Use
Curtain.
Show the steps and answer
- Block light.
- Sleep.
- Privacy.
Answer: Opaque curtains block light.
Did you know?
Black surfaces absorb most visible light, which is why a black car gets hotter than a white car in the sun.
Why this matters
Opaque materials give privacy, shade and shelter.
4. Explore: Three-group sort
Test ten materials and sort them into three groups.
- Shine a torch through each material.
- Note what you see.
- Sort into three groups.
- Record in a table.
Think about it: what did you notice?
What did you notice? The same torch gave very different results.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- An ___ material blocks all light.
- To ___ is to take in light.
- To ___ is to group by features.
- A ___ is a feature of a material.
Guided practice
Question 1. What is opaque?
No light through.
Question 2. Name one.
Wood.
Question 3. What do opaque objects make?
Dark shadows.
Independent practice
Level 1: Start
- What is opaque?
- Name one.
- What do opaque objects make?
- What is sort?
- What is a property?
Level 2: Grow
- Why curtains opaque?
- Why test?
- Why black hot?
Level 3: Stretch
- Sort ten materials.
- Explain a choice.
- Compare shadows.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Choose an opaque material for a screen.
Show a sample answer
Explain.
Another one. Tell a family member one thing from this lesson. Use the words you learned.
Show a sample answer
A clear sentence that uses at least one word from Words to know.
7. Common mistakes
Fix: It blocks light.
Fix: Some dark things are not.
8. Lesson summary and revision card
- I can define opaque.
- I can test materials.
- I can sort into three groups.
- I can choose materials for purposes.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- Opaque materials block light.
- We cannot see through them.
- Wood, metal and card are opaque.
- Opaque objects make dark shadows.
11. Next lesson
Next lesson: Shadows. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Define opaque. [1 mark]
- Sort three materials into groups. [3 marks]
- Describe a test for opacity. [3 marks]
- Explain why curtains are opaque. [2 marks]
- Safety rule? [1 mark]
Total: 10 marks.
Marking guide and model answers
- No light passes [1]
- 1 each
- Torch [1]; observe [1]; classify [1]
- Block light [1]; sleep or privacy [1]
- Any [1]
Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- What is opaque?
- Name one.
- What do opaque objects make?
- What is sort?
- What is a property?
- Why curtains opaque?
- Why test?
- Why black hot?
- Sort ten materials.
- Explain a choice.
Homework
Sort ten household materials into three light groups.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is opaque? | No light through. | 1 |
| 2. Name one. | Wood. | 1 |
| 3. What do opaque objects make? | Dark shadows. | 1 |
| 4. What is sort? | Group. | 1 |
| 5. What is a property? | Feature. | 1 |
| 6. Why curtains opaque? | Block light. | 1 |
| 7. Why test? | Sort fairly. | 1 |
| 8. Why black hot? | Absorbs. | 1 |
| 9. Sort ten materials. | Table. | 1 |
| 10. Explain a choice. | Sentence. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 No light through.; 2 Wood.; 3 Dark shadows.; 4 Group.; 5 Feature.. Level 2: 1 Block light.; 2 Sort fairly.; 3 Absorbs.. Level 3: 1 Table.; 2 Sentence.; 3 Sentence..
Quiz answers: 1 B, 2 C, 3 A, 4 B, 5 C, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 B, Challenge 2 C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Define opaque | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Test materials | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Sort into three groups | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Choose materials for purposes | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: “Opaque means invisible.” It blocks light.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Sort and use opaque materials.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child sorts materials by light. You do not need to be an expert to help.
- Test items at home.
- Ask “Opaque or not?”
- Use cool torches.
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: define opaque; test materials; sort into three groups; choose materials for purposes.
Prerequisite knowledge. Grade 3 physical ideas: forces, materials, and how to measure and record in fair tests.
Materials. Torch, samples. Low-resource options: use chalk or charcoal on a board or wall, drawings in the sand, and objects from the classroom instead of printed materials.
Preparation. Gather materials.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Close a curtain and ask, “Why is it dark?”
Explanation (10 min). Teach opaque.
Guided activity (10 min). Learners test.
Independent activity (10 min). Learners sort.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Light fully, partly or not?
Teacher explanation notes. Start with real objects and safe, hands-on observation. Then talk about what was seen, then draw and write. Always say “how do you know?”. Keep to the safety notes, and use local, safe materials.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and pictures, short sentences and a partner. Let learners point, show or draw instead of writing. Extension. Ask learners to find a new example at home and explain how they know.
Formative assessment. Listen to learners read and explain, ask “how do you know?”, and check the independent work.
Misconceptions. “Opaque means invisible.” It blocks light.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz, the 10-mark exam practice and the worksheet on this page. All answers and marking guides are in the answer sections above. Re-check every answer before use.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Sort and use opaque materials. Enrichment. Look for one new example near your home or school, draw it and explain it to someone. Homework. See above.
Teacher reflection. After teaching, record: which ideas learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points: Next Generation Science Standards, Cambridge Primary Science and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Research used to shape this lesson. Courseversity Science curriculum, Grade 4 Unit 4, topic 7; Next Generation Science Standards, waves and their applications (light); Cambridge Primary Science Stage 4, physics: light and dark; IB Primary Years Programme, how the world works. These sources informed the lesson.