You will learn
- Define physical and chemical changes.
- List signs of chemical change.
- Classify changes.
- Explain reversibility.
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
- Physical changes are usually reversible.
- Chemical changes make new substances.
- Signs include bubbles, colour change, heat or light and a new smell.
- Mass is conserved.
Words to know
a change with no new substance
a change that makes new substances
a substance that reacts
a new substance made in a reaction
1. Discover: The fizzing cup
Hawa adds baking soda to vinegar and it fizzes. Gas bubbles rise. “A new gas has formed,” says her teacher. “That is a chemical change. Melting ice is not: it is still water.”
Think: How could you tell the gas is new?
2. Understand: Types of change
Idea 1: Physical
A physical change does not make a new substance. Melting, freezing, dissolving, tearing and crushing are physical. Many can be reversed.
Idea 2: Chemical
A chemical change makes new substances (products) from starting substances (reactants). Burning, rusting, cooking an egg and baking soda with vinegar are chemical changes. Most cannot easily be reversed.
Idea 3: Signs
Signs of a chemical change: gas bubbles, a colour change, heat or light, a new smell or a solid forming. The total mass stays the same because no atoms are lost.
3. Worked examples
Example 1 (I show you): Classify
Changes.
- Melting.
- Rusting.
- Dissolving.
Answer: Physical or chemical.
Example 2 (We do it together): List
Signs.
- Gas.
- Colour.
- Heat.
Answer: Four signs.
Example 3 (You try): Explain
Reversible.
Show the steps and answer
- Ice to water.
- Back to ice.
- Egg stays cooked.
Answer: Physical vs chemical.
Did you know?
Every iron nail that rusts becomes a new substance, iron oxide, and can gain mass as it combines with oxygen.
Why this matters
Chemical changes power cooking, batteries, digestion and manufacturing.
4. Explore: Fizz test
In a tray, add a spoon of baking soda to a cup, then pour in a little vinegar and observe; compare with dissolving sugar in water and melting an ice cube.
- Set up a tray.
- Add baking soda.
- Pour vinegar.
- Compare with other changes.
Think about it: what did you notice?
What did you notice? New gas appeared only in the fizzing mix.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- A ___ change does not make a new substance.
- A ___ change makes new substances.
- A ___ is a substance that reacts.
- A ___ is a new substance made in a reaction.
Guided practice
Question 1. What is a physical change?
No new substance.
Question 2. What is a chemical change?
New substance.
Question 3. Name a sign.
Bubbles.
Independent practice
Level 1: Start
- What is a physical change?
- What is a chemical change?
- Name a sign.
- What is a product?
- Is melting chemical?
Level 2: Grow
- Why gas sign?
- Why not reverse?
- Why mass same?
Level 3: Stretch
- Test changes.
- Classify.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain how to tell a chemical change from a physical change.
Show a sample answer
Use signs.
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: Physical.
Fix: Conserved.
8. Lesson summary and revision card
- I can define physical and chemical changes.
- I can list signs of chemical change.
- I can classify changes.
- I can explain reversibility.
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
- Physical changes are usually reversible.
- Chemical changes make new substances.
- Signs include bubbles, colour change, heat or light and a new smell.
- Mass is conserved.
11. Next lesson
Next lesson: Forces. 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 physical and chemical change. [2 marks]
- List three signs of chemical change. [3 marks]
- Classify melting, rusting, cooking and dissolving. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- 1 each
- Four correct [3 marks]
- Any [1]; reason [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 a physical change?
- What is a chemical change?
- Name a sign.
- What is a product?
- Is melting chemical?
- Why gas sign?
- Why not reverse?
- Why mass same?
- Test changes.
- Classify.
Homework
List three physical and three chemical changes at home.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is a physical change? | No new substance. | 1 |
| 2. What is a chemical change? | New substance. | 1 |
| 3. Name a sign. | Bubbles. | 1 |
| 4. What is a product? | New substance. | 1 |
| 5. Is melting chemical? | No. | 1 |
| 6. Why gas sign? | New substance. | 1 |
| 7. Why not reverse? | Substances changed. | 1 |
| 8. Why mass same? | Atoms kept. | 1 |
| 9. Test changes. | Table. | 1 |
| 10. Classify. | Chart. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 No new substance.; 2 New substance.; 3 Bubbles.; 4 New substance.; 5 No.. Level 2: 1 New substance.; 2 Substances changed.; 3 Atoms kept.. Level 3: 1 Table.; 2 Chart.; 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 physical and chemical changes | 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 List signs of chemical change | 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 Classify changes | 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 Explain reversibility | 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: “Dissolving is a chemical change.” Physical.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Classify changes.
- 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 physical and chemical changes. You do not need to be an expert to help.
- Watch fruit brown.
- Ask “Is it new?”
- Wear eye protection.
- 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 physical and chemical changes; list signs of chemical change; classify changes; explain reversibility.
Prerequisite knowledge. Grade 5 ideas: states of matter, changes of state, mixtures and dissolving.
Materials. Baking soda, vinegar, cups, trays, goggles. 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. Set out trays.
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). Cut a banana and let it brown and ask, “Is this the same as cutting?”
Explanation (10 min). Teach changes.
Guided activity (10 min). Learners test.
Independent activity (10 min). Learners classify.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. New substance? What signs?
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. “Dissolving is a chemical change.” Physical.
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. Classify changes. 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 6 Unit 5, topic 10; Next Generation Science Standards, structure and properties of matter; Cambridge Lower Secondary Science, chemistry; IB Primary Years Programme, how the world works. These sources informed the lesson.