All lessons › Air: the invisible stuff › Lesson 2
Australian primary science · Year 5 · Lesson 2 of 3
Seeing the jiggle
Inquiry question: How did scientists prove that matter is made of tiny moving particles?
Marked no materials needed
Using a model
What students learn
The particle model was not discovered by one person. It grew over more than 2000 years, as each scientist observed, explained and tested the work of others, until the evidence was strong enough to convince nearly everyone.
Success criteria
- I can describe what Brown, Einstein and Perrin each did.
- I can explain how each built on the work of others.
- I can use a model to explain why tiny grains jiggle in water.
Preparation and materials
Before this lesson: Students can describe air as a gas made of particles (lesson 1).
- One screen or projector to show this lesson’s student view (the particle timeline) (or print one student view per pair) — 1
- Workbooks or scrap paper, and pencils — 26
Teacher setup
- Open this lesson’s student view (the particle timeline) on your screen, or print the student view if the internet is unreliable.
- No other preparation is needed.
Safety and adaptations
Follow school science and equipment risk assessment procedures for the materials used.
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 read the particle timeline in the student view.
- For each person, write what they observed or did, and whose work they built on.
- Watch (or take part in) the jiggle model. Write what each part of the model stands for.
- Draw a pollen grain with arrows from water particles hitting it unevenly.
- Write one limitation of our model (how it is not like the real thing).
Teacher modelling prompt
Run the model with the class: one student in the middle is the “pollen grain” (standing still, arms folded); six students are “water particles” walking slowly in random directions around them, gently tapping the grain’s shoulder only when they bump it. Think aloud: “More taps from the left this second, so the grain shuffles right. Now more from the front. The grain zig-zags, even though no one can see the water particles.”
Record and explain evidence
Recording question: How did scientists prove that matter is made of tiny moving particles?
| Who and when | What they observed or did | Whose work they built on | How it helped the particle idea |
|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
What does the timeline show?
Check understanding
What should pupils know? What made the tiny grains in Brown’s water jiggle?
Explain with evidence: Why was it important that Brown published exactly what he saw, even though he couldn’t explain it?
Apply the idea: Our jiggle model is not exactly like real particles. Give one way it is different. Stretch (older students): explain why scientists needed both an explanation (Einstein) and measurements (Perrin) before they were convinced.
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.