You will learn
- Describe the three states.
- Compare shape and volume.
- Explain compressibility.
- Link changes of state to heat.
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
Words to know
keeps its own shape and volume
has its own volume but takes the shape of its container
spreads to fill any container
to squeeze into less space
1. Discover: The three bottles
Naana has a bottle of stones, a bottle of juice and an empty-looking bottle with a lid. She pours the juice into a glass: it takes the glass shape. She presses a syringe full of air: it squeezes. “The stones, juice and air are a solid, liquid and gas,” she says.
Think: Which can be squeezed?
2. Understand: States
Idea 1: Solid
A solid has a fixed shape and volume. Its particles are close and vibrate in place.
Idea 2: Liquid and gas
A liquid has a fixed volume but flows into the container shape. A gas has no fixed shape or volume and fills its container.
Idea 3: Changing state
Heating can melt solids and boil liquids. Cooling can condense gases and freeze liquids. A gas can be compressed but solids and liquids hardly can.
3. Worked examples
Example 1 (I show you): Sort
Stone.
- Solid.
- Fixed.
- Shape.
Answer: Solid.
Example 2 (We do it together): Sort
Juice.
- Liquid.
- Flows.
- Container.
Answer: Liquid.
Example 3 (You try): Sort
Air.
Show the steps and answer
- Gas.
- Fills.
- Squeezes.
Answer: Gas.
Did you know?
Plasma, the stuff of lightning and stars, is sometimes called the fourth state of matter.
Why this matters
Knowing states explains cooking, weather and machines.
4. Explore: State sort
Use syringes with air and water and solid objects to test shape, volume and compression.
- Fill a syringe with air.
- Press the plunger.
- Fill with water.
- Press and compare.
Think about it: what did you notice?
What did you notice? Air compressed; water barely did.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- A ___ keeps its shape.
- A ___ takes the shape of its container.
- A ___ fills all the space.
- To ___ is to squeeze into less space.
Guided practice
Question 1. What is a solid?
Fixed shape.
Question 2. What is a liquid?
Flows.
Question 3. What is a gas?
Fills.
Independent practice
Level 1: Start
- What is a solid?
- What is a liquid?
- What is a gas?
- Can gases compress?
- Can liquids compress?
Level 2: Grow
- Why gases fill?
- Why liquids flow?
- Why solids keep shape?
Level 3: Stretch
- Run the syringe test.
- Sort objects.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Compare water and air in a syringe.
Show a sample answer
Use compression.
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: They do.
Fix: Container shape.
8. Lesson summary and revision card
- I can describe the three states.
- I can compare shape and volume.
- I can explain compressibility.
- I can link changes of state to heat.
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
- Solids keep shape.
- Liquids flow and take the container shape.
- Gases fill all the space and can be compressed.
- Heat can change the state.
11. Next lesson
Next lesson: Particle model introduction. 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 solid, liquid and gas. [3 marks]
- Compare compression of air and water. [3 marks]
- Link change of state to heat. [2 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Air compresses [1]; water barely [1]; reason [1]
- Heat [1]; state change [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 a solid?
- What is a liquid?
- What is a gas?
- Can gases compress?
- Can liquids compress?
- Why gases fill?
- Why liquids flow?
- Why solids keep shape?
- Run the syringe test.
- Sort objects.
Homework
List three solids, liquids and gases at home.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is a solid? | Fixed shape. | 1 |
| 2. What is a liquid? | Flows. | 1 |
| 3. What is a gas? | Fills. | 1 |
| 4. Can gases compress? | Yes. | 1 |
| 5. Can liquids compress? | Hardly. | 1 |
| 6. Why gases fill? | Free particles. | 1 |
| 7. Why liquids flow? | Slide. | 1 |
| 8. Why solids keep shape? | Fixed positions. | 1 |
| 9. Run the syringe test. | Table. | 1 |
| 10. Sort objects. | Table. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Fixed shape.; 2 Flows.; 3 Fills.; 4 Yes.; 5 Hardly.. Level 2: 1 Free particles.; 2 Slide.; 3 Fixed positions.. Level 3: 1 Table.; 2 Table.; 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 Describe the three states | 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 Compare shape and volume | 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 compressibility | 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 Link changes of state to heat | 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: “Gases have no mass.” They do.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Compare states of matter.
- 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 compares states of matter. You do not need to be an expert to help.
- Sort kitchen items.
- Ask “Solid, liquid or gas?”
- 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: describe the three states; compare shape and volume; explain compressibility; link changes of state to heat.
Prerequisite knowledge. Grade 4 ideas: properties of materials, states of matter, melting, freezing, evaporation, dissolving and reversible changes.
Materials. Syringes, water, objects. 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 syringes.
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). Squeeze a sealed bag of air and ask, “Why can we squeeze it?”
Explanation (10 min). Teach states.
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. Shape? Volume? Squeeze?
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. “Gases have no mass.” They do.
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. Compare states of matter. 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 5 Unit 4, topic 3; Next Generation Science Standards, structure and properties of matter; Cambridge Primary Science Stage 5, chemistry: states of matter and materials; IB Primary Years Programme, how the world works. These sources informed the lesson.