All lessons › Kitchen science: squish, bubble and freeze › Lesson 1
Australian primary science · Years 3–4 · Lesson 1 of 4
Oobleck: solid or liquid?
Inquiry question: Is oobleck a solid or a liquid?
Check practical materials
Observing and testing
What students learn
Solids keep their shape and liquids flow; some mixtures, like oobleck, can behave like both depending on how we push them.
Success criteria
- I can describe how solids and liquids behave.
- I can do the same tests carefully and record what happens.
- I can use my observations to decide whether oobleck acts like a solid, a liquid or both.
Preparation and materials
Before this lesson: Students can name some solids and liquids.
- Cornflour — 2 boxes (about 1 kg)
- Water — 1 jug per table
- Bowls or plastic containers — 13
- Measuring cups (1/2 and 1/4 cup) — 13 sets
- Spoons — 13
- Trays or newspaper — 13
- Paper towel — 1 roll
- Food colouring (optional) — 1 bottle
Teacher setup
- Put 1/2 cup of cornflour in each bowl before the lesson.
- Cover tables with trays or newspaper.
Safety and adaptations
- Don’t pour oobleck down the sink.
- Keep your hands away from your eyes and mouth.
- Wipe spills straight away 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.
- Add 1/4 cup of water to the cornflour slowly. Stir until it is thick like custard.
- Slow poke: push one finger in slowly. Record what happens.
- Fast tap: tap the surface hard and fast. Record what happens.
- Squeeze a handful into a ball, then open your hand. Record what happens.
- Pour some from a spoon. Record what happens.
- Decide: for each test, did it act like a solid or a liquid?
Teacher modelling prompt
Hold up a cup of water. Push a finger in slowly, then tap the surface quickly. Say: “I’m doing exactly the same two tests you will do. I’m not telling you what oobleck will do.” Show how to record the test and the result in two columns.
Record and explain evidence
Recording question: Is oobleck a solid or a liquid?
| Test | What happened | Acted like a solid or a liquid? |
|---|---|---|
| ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
Which claim fits all of our evidence, and which test decides it?
Check understanding
What should pupils know? Write one property of a solid and one property of a liquid.
Explain with evidence: Mia says oobleck is just a liquid. Which observation could you show her?
Apply the idea: Is toothpaste a solid or a liquid? Give a reason.
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.