You will learn
- Compare the three states.
- Use a table.
- Draw particles in each state.
- Sort materials.
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
solid, liquid or gas
a tiny piece of matter
to find similarities and differences
not changing
1. Discover: The three jars
Esi has three jars: one with stones, one with water and one with only air. “Stones keep their shape,” she says. “Water fills the jar from the bottom. Air fills the whole jar.” Her teacher draws dots in each jar. “These show the particles.”
Think: Why are the dots different?
2. Understand: States
Idea 1: The table
A solid has fixed shape and volume. A liquid has fixed volume but takes the container’s shape. A gas has neither and fills the whole container.
Idea 2: Particles
Particles in a solid are close and stay in place. In a liquid they are close but slide. In a gas they are far apart and move freely.
Idea 3: Sorting
To sort a material, ask: Does it keep its shape? Does it fill its container? Can it be squeezed?
3. Worked examples
Example 1 (I show you): Sort
Stone.
- Keeps shape.
- Solid.
- Fixed.
Answer: A stone is a solid.
Example 2 (We do it together): Sort
Milk.
- Flows.
- Container shape.
- Liquid.
Answer: Milk is a liquid.
Example 3 (You try): Sort
Steam.
Show the steps and answer
- Fills space.
- Compressible.
- Gas.
Answer: Steam is a gas.
Did you know?
There is a fourth state of matter called plasma, found in lightning and stars.
Why this matters
Knowing states helps us explain freezing, melting and many everyday changes.
4. Explore: Three-state sort
Sort materials into solid, liquid or gas.
- Collect samples or pictures.
- Test each for shape and flow.
- Sort into three columns.
- Draw particles for each.
Think about it: what did you notice?
What did you notice? Particle drawings matched how each state behaved.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- ___ have a fixed shape.
- ___ flow but have a fixed volume.
- ___ fill their container.
- Particles in gases are ___ apart.
Guided practice
Question 1. Name the three states.
Solid, liquid, gas.
Question 2. Which keeps shape?
Solid.
Question 3. Which fills a container?
Gas.
Independent practice
Level 1: Start
- Name the three states.
- Which keeps shape?
- Which fills a container?
- Which flows but has fixed volume?
- What are particles?
Level 2: Grow
- Why do gases compress?
- Why do solids keep shape?
- Why do liquids flow?
Level 3: Stretch
- Fill in a comparison table.
- Draw particles.
- Sort ten materials.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Name one solid, liquid and gas at home.
Show a sample answer
Table, water, air.
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: Weight varies.
Fix: They are matter.
8. Lesson summary and revision card
- I can compare the three states.
- I can use a table.
- I can draw particles in each state.
- I can sort materials.
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 have a fixed shape and volume.
- Liquids have a fixed volume but no fixed shape.
- Gases have neither.
- Particles are close in solids, further in liquids, far in gases.
11. Next lesson
Next lesson: Material properties. 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.
- Compare solid, liquid and gas. [3 marks]
- Draw particles in each state. [3 marks]
- Sort two materials. [2 marks]
- Name the fourth state. [1 mark]
- Safety rule? [1 mark]
Total: 10 marks.
Marking guide and model answers
- Solid fixed shape [1]; liquid fixed volume [1]; gas fills container [1]
- Solid close [1]; liquid sliding [1]; gas far [1]
- Two correct [1 each]
- Plasma [1]
- Any sensible rule [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
- Name the three states.
- Which keeps shape?
- Which fills a container?
- Which flows but has fixed volume?
- What are particles?
- Why do gases compress?
- Why do solids keep shape?
- Why do liquids flow?
- Fill in a comparison table.
- Draw particles.
Homework
Find six materials at home and sort them as solid, liquid or gas.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. Name the three states. | Solid, liquid, gas. | 1 |
| 2. Which keeps shape? | Solid. | 1 |
| 3. Which fills a container? | Gas. | 1 |
| 4. Which flows but has fixed volume? | Liquid. | 1 |
| 5. What are particles? | Tiny pieces. | 1 |
| 6. Why do gases compress? | Space between particles. | 1 |
| 7. Why do solids keep shape? | Particles fixed. | 1 |
| 8. Why do liquids flow? | Particles slide. | 1 |
| 9. Fill in a comparison table. | Table. | 1 |
| 10. Draw particles. | Diagram. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Solid, liquid, gas.; 2 Solid.; 3 Gas.; 4 Liquid.; 5 Tiny pieces.. Level 2: 1 Space between particles.; 2 Particles fixed.; 3 Particles slide.. Level 3: 1 Table.; 2 Diagram.; 3 Table..
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 Compare 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 Use a table | 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 Draw particles in each 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 |
| O4 Sort 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 |
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: “All liquids are heavy.” Weight varies.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Compare the three 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 solids, liquids and gases. You do not need to be an expert to help.
- Sort kitchen items.
- Ask, “Solid, liquid or gas?”
- Wipe 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: compare the three states; use a table; draw particles in each state; sort materials.
Prerequisite knowledge. Grade 2 matter ideas: solids and liquids, air and water, and the properties of everyday materials.
Materials. Samples, pictures, tables. 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 sorting cards.
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 three jars and ask, “What is the difference?”
Explanation (10 min). Teach states.
Guided activity (10 min). Learners sort.
Independent activity (10 min). Learners draw particles.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Which state? How do you know?
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. “All liquids are heavy.” Weight varies.
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 the three 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 3 Unit 5, topic 5; Next Generation Science Standards, structure and properties of matter; Cambridge Primary Science Stage 3, materials; IB Primary Years Programme, how the world works. These sources informed the lesson.