All lessons › Solids, liquids and gases › Lesson 2
Australian primary science · Year 5 · Lesson 2 of 3
Shape, pour and squash
Inquiry question: How can we tell if something is a solid, a liquid or a gas?
Check practical materials
Classifying
What students learn
Solids keep their shape. Liquids flow and take the shape of their container but keep the same amount. Gases spread to fill their container and can be squashed. The particle model explains each one.
Success criteria
- I can test a sample for shape, flow and squashing.
- I can sort samples into solid, liquid and gas using my results.
- I can explain a result using particles.
Preparation and materials
Before this lesson: Students can describe the particle model for solids, liquids and gases (lesson 1).
- Small solid objects: an eraser or wooden block — 13
- Cups of water — 13
- Containers of different shapes: a tall cup, a bowl and a zip-lock bag — 13 sets
- Dry rice (or sand), about half a cup — 13
- Empty plastic drink bottles with lids (about 600 mL) — 26 (2 per pair)
- Zip-lock bags (to fill with air) — 13
- Trays or old towels for spills — 13
Teacher setup
- For each pair, fill one bottle to the very top with water and screw on the lid. Leave the other bottle empty (full of air) and screw on the lid.
- Put a tray under each pair’s set of containers.
Safety and adaptations
- Wipe up spills straight away so nobody slips.
- Don’t put rice or sand in mouths, noses or ears.
- Don’t squeeze bottles towards anyone’s face.
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.
- Pairs test each sample: eraser, water, rice and air (in the zip-lock bag and the empty bottle).
- Put or pour each into two different containers. Does its shape change?
- Does it pour or flow?
- Squeeze the water bottle and the air bottle. Which squashes more?
- Record the results and decide solid, liquid or gas.
Teacher modelling prompt
Model one sample: “I pour the water from the cup into the bowl. It changes shape to fit the bowl, but there is still the same amount. So it flows and takes the container’s shape. Now I squeeze the full water bottle: it hardly squashes. The particles are already close together.”
Record and explain evidence
Recording question: How can we tell if something is a solid, a liquid or a gas?
| Sample | Keeps its own shape? | Pours or flows? | Can we squash it smaller? | Solid, liquid or gas? |
|---|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
Use your table to decide whose claim has better evidence.
Check understanding
What should pupils know? Name one property each of a solid, a liquid and a gas.
Explain with evidence: Use particles to explain why the air bottle squashed more than the water bottle.
Apply the idea: Why do bike tyres use air and not water inside them?
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.