You will learn
- Name changes of state.
- Explain them with particles.
- Explain melting and boiling points.
- Observe melting ice.
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
- Changes of state are physical, reversible changes.
- Heating gives particles more energy.
- Melting and boiling points are fixed for pure substances.
- Mass stays the same.
Words to know
solid to liquid
liquid to gas at the surface
gas to liquid
solid directly to gas
1. Discover: The mist on the glass
Kofi takes a cold glass of water outside on a humid day. Droplets appear on the outside. “Water vapour in the air hit the cold glass and condensed,” says his teacher. “The water did not leak through the glass.”
Think: Where did the droplets come from?
2. Understand: States change
Idea 1: Changes
Melting (solid to liquid), freezing (liquid to solid), evaporation and boiling (liquid to gas), condensation (gas to liquid) and sublimation (solid to gas, like dry ice).
Idea 2: Particles
Heating gives particles more energy so they move more and break free of each other. Cooling slows them and lets them clump together again.
Idea 3: Points
Pure water melts at 0°C and boils at 100°C at sea level. These fixed temperatures help identify substances. The total mass stays the same during a change of state.
3. Worked examples
Example 1 (I show you): Name
Changes.
- Melting.
- Freezing.
- Condensation.
Answer: Six changes.
Example 2 (We do it together): Explain
Melting.
- More energy.
- Move more.
- Break free.
Answer: Particles loosen.
Example 3 (You try): State
Points.
Show the steps and answer
- 0°C.
- 100°C.
- Fixed.
Answer: Water values.
Did you know?
Dry ice (solid carbon dioxide) turns straight to gas at about −78°C without becoming liquid, but it is dangerous to touch.
Why this matters
Changes of state explain weather, cooking and manufacturing.
4. Explore: Melting ice
Place ice cubes in warm water and cold water in two clear cups, time how long each takes to melt and record temperatures with a thermometer.
- Fill two cups.
- Add equal ice.
- Time melting.
- Record temperature.
Think about it: what did you notice?
What did you notice? Ice melted faster in warm water.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- ___ is solid to liquid.
- ___ is liquid to gas at the surface.
- ___ is gas to liquid.
- ___ is solid directly to gas.
Guided practice
Question 1. What is melting?
Solid to liquid.
Question 2. What is freezing?
Liquid to solid.
Question 3. What is evaporation?
Liquid to gas.
Independent practice
Level 1: Start
- What is melting?
- What is freezing?
- What is evaporation?
- What is condensation?
- Water boils at?
Level 2: Grow
- Why energy?
- Why fixed point?
- Why droplets?
Level 3: Stretch
- Run the test.
- Draw particles.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain what happens to particles when ice melts.
Show a sample answer
Use energy.
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: From the air.
Fix: Same.
8. Lesson summary and revision card
- I can name changes of state.
- I can explain them with particles.
- I can explain melting and boiling points.
- I can observe melting ice.
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
- Changes of state are physical, reversible changes.
- Heating gives particles more energy.
- Melting and boiling points are fixed for pure substances.
- Mass stays the same.
11. Next lesson
Next lesson: Mixtures. 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 melting and condensation. [2 marks]
- Name four changes of state. [2 marks]
- Explain melting with particles. [4 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Any four [2]
- Energy in [1]; more movement [1]; break from pattern [1]; liquid [1]
- 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 melting?
- What is freezing?
- What is evaporation?
- What is condensation?
- Water boils at?
- Why energy?
- Why fixed point?
- Why droplets?
- Run the test.
- Draw particles.
Homework
Find three changes of state around your home.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is melting? | Solid to liquid. | 1 |
| 2. What is freezing? | Liquid to solid. | 1 |
| 3. What is evaporation? | Liquid to gas. | 1 |
| 4. What is condensation? | Gas to liquid. | 1 |
| 5. Water boils at? | 100°C. | 1 |
| 6. Why energy? | Move more. | 1 |
| 7. Why fixed point? | Pure substance. | 1 |
| 8. Why droplets? | Condensation. | 1 |
| 9. Run the test. | Table. | 1 |
| 10. Draw particles. | Diagram. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Solid to liquid.; 2 Liquid to solid.; 3 Liquid to gas.; 4 Gas to liquid.; 5 100°C.. Level 2: 1 Move more.; 2 Pure substance.; 3 Condensation.. Level 3: 1 Table.; 2 Diagram.; 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 Name changes of state | 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 Explain them with particles | 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 Explain melting and boiling points | 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 Observe melting ice | 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: “The droplets come through the glass.” From the air.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain changes of state.
- 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 studies changes of state. You do not need to be an expert to help.
- Watch ice melt.
- Ask “What is happening?”
- Mind spills.
- 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: name changes of state; explain them with particles; explain melting and boiling points; observe melting ice.
Prerequisite knowledge. Grade 5 ideas: states of matter, changes of state, mixtures and dissolving.
Materials. Ice, cups, thermometers, warm water. 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. Prepare ice.
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). Show a cold glass sweating and ask, “Where did that water come from?”
Explanation (10 min). Teach changes of state.
Guided activity (10 min). Learners test.
Independent activity (10 min). Learners explain.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Which change? What energy change?
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. “The droplets come through the glass.” From the air.
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. Explain changes of state. 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 7; 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.