You will learn
- Describe gases.
- Say they fill containers.
- Show that air can be squeezed.
- Name examples of gases.
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
- Gases spread to fill any container.
- They have no fixed shape or volume.
- They can be compressed.
- Air is a mixture of gases.
Words to know
matter with no fixed shape or volume
to squeeze into a smaller space
to spread out
the mix of gases around us
1. Discover: The syringe of air
Fiifi holds a sealed plastic syringe full of air and pushes the plunger. It moves only part of the way. “The air is being squeezed,” says the teacher. “Gases can be compressed. Liquids cannot.”
Think: Why does the air spring back?
2. Understand: Gases
Idea 1: Gas properties
A gas has no fixed shape or volume. It spreads to fill the whole container, such as air in a balloon.
Idea 2: Compressing
Gases can be compressed into a smaller space and can expand again. This is why a bicycle pump works.
Idea 3: Air
Air is a mixture of gases, mainly nitrogen and oxygen. Other gases include carbon dioxide and water vapour.
3. Worked examples
Example 1 (I show you): Fill
Balloon.
- Air fills it.
- Spreads.
- Gas.
Answer: Gases fill their container.
Example 2 (We do it together): Squeeze
Syringe.
- Air compresses.
- Spring back.
- Gas.
Answer: Gases can be compressed.
Example 3 (You try): Name
What is air?
Show the steps and answer
- Mixture.
- Nitrogen, oxygen.
- Gases.
Answer: Air is a mixture of gases.
Did you know?
Air is about 78 percent nitrogen and about 21 percent oxygen.
Why this matters
Gases such as oxygen and carbon dioxide are essential to breathing and plant growth.
4. Explore: Squeeze the syringe
Show that air can be compressed.
- Fill a syringe with air.
- Seal the tip with a finger.
- Push the plunger.
- Compare with a syringe of water.
Think about it: what did you notice?
What did you notice? Air squeezed, water did not.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- Gases fill the ___.
- Gases can be ___.
- Air is a ___ of gases.
- Gases have no fixed ___.
Guided practice
Question 1. What is a gas?
No fixed shape.
Question 2. Can gases be squeezed?
Yes.
Question 3. What is air?
Mixture of gases.
Independent practice
Level 1: Start
- What is a gas?
- Can gases be squeezed?
- What is air?
- Name a gas.
- What does a gas fill?
Level 2: Grow
- Why does a pump work?
- Why does air spring back?
- Why can liquids not compress?
Level 3: Stretch
- Do the syringe test.
- Draw a balloon.
- Explain compression.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Name three gases.
Show a sample answer
Oxygen, carbon dioxide, nitrogen.
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 are matter.
Fix: They can.
8. Lesson summary and revision card
- I can describe gases.
- I can say they fill containers.
- I can show that air can be squeezed.
- I can name examples of gases.
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
- Gases spread to fill any container.
- They have no fixed shape or volume.
- They can be compressed.
- Air is a mixture of gases.
11. Next lesson
Next lesson: Comparing states of matter. 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.
- What is a gas? [2 marks]
- Describe the syringe test. [3 marks]
- What is air? [2 marks]
- Name two gases. [2 marks]
- Safety rule? [1 mark]
Total: 10 marks.
Marking guide and model answers
- No fixed shape [1]; no fixed volume [1]
- Push air [1]; compresses [1]; spring back [1]
- Mixture [1]; of gases [1]
- 1 each
- 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 a gas?
- Can gases be squeezed?
- What is air?
- Name a gas.
- What does a gas fill?
- Why does a pump work?
- Why does air spring back?
- Why can liquids not compress?
- Do the syringe test.
- Draw a balloon.
Homework
Find three gases at home (like air in a tyre) and describe them.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is a gas? | No fixed shape. | 1 |
| 2. Can gases be squeezed? | Yes. | 1 |
| 3. What is air? | Mixture of gases. | 1 |
| 4. Name a gas. | Oxygen. | 1 |
| 5. What does a gas fill? | Its container. | 1 |
| 6. Why does a pump work? | Compresses air. | 1 |
| 7. Why does air spring back? | It expands. | 1 |
| 8. Why can liquids not compress? | Particles close. | 1 |
| 9. Do the syringe test. | Observation. | 1 |
| 10. Draw a balloon. | Diagram. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 No fixed shape.; 2 Yes.; 3 Mixture of gases.; 4 Oxygen.; 5 Its container.. Level 2: 1 Compresses air.; 2 It expands.; 3 Particles close.. Level 3: 1 Observation.; 2 Diagram.; 3 Paragraph..
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 gases | 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 Say they fill containers | 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 Show that air can be squeezed | 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 Name examples of gases | 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 are nothing.” They are matter.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Describe gas properties.
- 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 learns about gases. You do not need to be an expert to help.
- Use a bicycle pump.
- Ask, “What is inside?”
- Keep syringes away from faces.
- 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 gases; say they fill containers; show that air can be squeezed; name examples of gases.
Prerequisite knowledge. Grade 2 matter ideas: solids and liquids, air and water, and the properties of everyday materials.
Materials. Syringes without needles, balloons, 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. Check syringes are needle-free.
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 balloon and ask, “What is pushing back?”
Explanation (10 min). Teach gases.
Guided activity (10 min). Learners test syringes.
Independent activity (10 min). Learners compare.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. Can it be squeezed? Does it fill the container?
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 are nothing.” They are matter.
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. Describe gas properties. 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 4; 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.