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Australian primary science · Year 3 · Lesson 2 of 3
Solid or liquid?
Inquiry question: How can we tell if something is a solid or a liquid?
Check practical materials
Classifying
What students learn
Solids keep their own shape. Liquids flow and take the shape of their container. Some solids, like sand, can be poured because they are made of lots of tiny solid pieces.
Success criteria
- I can test whether something keeps its own shape.
- I can test whether something flows.
- I can sort tricky things like sand and honey and give a reason.
Preparation and materials
Before this lesson: Students know the words solid and liquid (lesson 1).
- Water — 1 small cup per pair
- Ice cubes — 13 (in an esky until needed)
- Pebbles from outside — 13
- Sand from the sandpit — 2 spoons per pair
- Honey, shampoo or dishwashing liquid — 2 spoons per pair
- Salt or sugar — 2 spoons per pair
- Plastic cups — 13 sets of 6 (one per item), or reuse and rinse
- Paper plates — 13
- Spoons — 13
- Paper towel — 13 sheets
- Magnifying glasses, if you have them — Optional
Teacher setup
- Put a small amount of each item in a labelled cup for each pair (a tray per pair helps).
- Keep ice in an esky until needed.
- Print one investigation record per pair.
Safety and adaptations
- Don’t taste anything: science samples are not food.
- Check allergies before using honey.
- Shampoo and dishwashing liquid sting eyes: keep hands away from faces.
- Wash hands after the lesson and wipe up spills so no one slips.
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 item: tip or move it from its cup onto the plate.
- Ask: did its shape change to fit? Can we pick it up? Does it flow?
- Look closely at a few grains of sand or salt on paper towel (a magnifier helps).
- Record the results and decide: solid or liquid?
- Choose one tricky item and explain your choice to another pair.
Teacher modelling prompt
Pour water from a tall cup onto a plate: “It spread out to fit the plate, so it is a liquid.” Move a pebble from the cup to the plate: “Same shape. It is a solid.” Then pour sand onto the plate: “Hmm, it pours! But look: it makes a heap. Let’s look closely at one grain.”
Record and explain evidence
Recording question: How can we tell if something is a solid or a liquid?
| Thing | Keeps its own shape? | Flows or pours? | Solid or liquid? | Why we think so |
|---|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
Whose reason is stronger? Use your test results.
Check understanding
What should pupils know? Name one property of a solid and one property of a liquid.
Explain with evidence: Is salt a solid or a liquid? Give a reason.
Apply the idea: Milk is poured from a carton into a bowl. What happens to its shape? What stays the same?
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.