All lessons › Air: the invisible stuff › Lesson 1
Australian primary science · Year 5 · Lesson 1 of 3
Is air really something?
Inquiry question: Can an “empty” cup keep a piece of paper dry underwater?
Check practical materials
Testing an idea
What students learn
Air is matter: it is a gas made of particles that are far apart and moving fast in all directions. Air particles take up space and push on things, so air can keep water out, and they can be squashed a little closer together.
Success criteria
- I can make a reasoned prediction before each test.
- I can describe what happened to the paper and the water.
- I can explain my observations using a particle model of air.
Preparation and materials
Before this lesson: Students know that solids, liquids and gases are three states of matter, and that air is a gas.
- Clear plastic cups (any cups work, but clear ones are easier to watch) — 13
- Paper towel or tissue — 13 sheets
- Large tub, bucket or deep sink of water (one per group, or one for a demonstration) — 3–6
- Plastic shopping or bread bags — 13
- Empty plastic drink bottles with lids — 13
- Old towels or newspaper for spills — A few
Teacher setup
- Fill tubs or buckets with water deep enough to push a cup under completely.
- Put the tubs on towels or outside on a table.
- Print one investigation record per pair.
Safety and adaptations
- Wipe up spills immediately so no one slips.
- Plastic bags: never put a bag over your head or face; the teacher collects them afterwards.
- If working outside, wear hats.
Review your school policies and curriculum requirements before teaching.
How to investigate
The lesson sequence should leave pupils with evidence to interpret, not only an activity to finish.
- Test 1: scrunch dry paper towel tightly into the bottom of the cup. Predict, then push the cup straight down into the water upside down, hold for 5 seconds, and lift straight up. Is the paper dry?
- Test 2: do it again, but tilt the cup while it is underwater. What comes out? What happens to the paper?
- Test 3: push the open bottle (no lid) down into the water, mouth first. Then squeeze it underwater. What do you see?
- Test 4: scoop air into a plastic bag, twist the top shut, and squeeze gently. Does it squash? Does it push back?
- For each test, draw what you think the air particles are doing.
Teacher modelling prompt
Hold up a cup. Think aloud: “I predict the paper will stay dry, because the cup isn’t really empty: it’s full of air particles. If they take up space, the water can’t get in.” Push it straight down, lift it straight up, and pull out the dry paper. Ask: what would happen if I tilted it?
Record and explain evidence
Recording question: Can an “empty” cup keep a piece of paper dry underwater?
| Test | Prediction and reason | What we observed | What the air particles were doing (draw it) |
|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
Which test gives evidence for Raj’s idea?
Check understanding
What should pupils know? Is an “empty” cup really empty? Explain.
Explain with evidence: Explain why water rushed into the cup when you tilted it underwater.
Apply the idea: Why can you squash a bag of air a little, but not a bag of water? Stretch (older students): draw particle diagrams of the bag of air and the bag of water to explain.
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.