You will learn
- Link temperature to particle speed.
- Explain diffusion.
- Describe Brownian motion.
- Compare states.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- Hotter means faster particles.
- Diffusion is faster when warmer.
- Gases diffuse fastest.
- Brownian motion supports the model.
Words to know
how hot or cold something is
energy of movement
spreading of particles
random jiggling of tiny visible bits caused by particle hits
1. Discover: The pollen dance
In 1827 botanist Robert Brown saw pollen grains in water jiggling randomly under a microscope. Years later Albert Einstein explained: invisible water particles were bumping the grains. “The jiggling is evidence for moving particles,” says Ms Quaye.
Think: Why would the jiggling be faster in warm water?
2. Understand: Movement
Idea 1: Speed
Particles have kinetic energy. At higher temperature they move faster on average. Even in a solid they vibrate more.
Idea 2: Diffusion
Diffusion is fastest in gases, slower in liquids and very slow in solids, because particles move freely in gases and are held in solids.
Idea 3: Brownian motion
Brownian motion is the random jiggling of tiny visible bits caused by unseen, fast-moving particles hitting them.
3. Worked examples
Example 1 (I show you): Predict
Warm vs cold.
- Faster.
- Spreads quickly.
- Compare.
Answer: Warm is faster.
Example 2 (We do it together): Rank
Diffusion.
- Gas.
- Liquid.
- Solid.
Answer: Gas fastest.
Example 3 (You try): Explain
Brownian.
Show the steps and answer
- Hits.
- Jiggle.
- Evidence.
Answer: Support for particles.
Did you know?
Einstein’s 1905 explanation of Brownian motion helped convince scientists that atoms are real.
Why this matters
Particle movement explains smells, cooling, drying and mixing.
4. Explore: Warm vs cold diffusion
Add a drop of food colouring to cold, room-temperature and warm (not hot) water in clear cups and time how long until the colour reaches the edge.
- Fill three cups.
- Add one drop to each.
- Time spreading.
- Compare.
Think about it: what did you notice?
What did you notice? Warm water spread fastest.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- ___ is how hot or cold something is.
- ___ energy is energy of movement.
- ___ is the spreading of particles.
- ___ motion is random jiggling.
Guided practice
Question 1. What is temperature?
Hot or cold.
Question 2. What is kinetic energy?
Movement energy.
Question 3. What is diffusion?
Spreading.
Independent practice
Level 1: Start
- What is temperature?
- What is kinetic energy?
- What is diffusion?
- Who saw jiggling?
- Hotter means?
Level 2: Grow
- Why warm faster?
- Why gases fastest?
- Why Brownian?
Level 3: Stretch
- Run the test.
- Graph.
- Explain.
Answers are in the answer key below. Try first, then check.
6. Apply: Science in everyday life
Explain why dye spreads faster in warm water.
Show a sample answer
Use particles.
Another one. Tell a family member one thing from this lesson. Use the words you learned.
Show a sample answer
A clear sentence that uses at least one word from Words to know.
7. Common mistakes
Fix: They still move.
Fix: Much slower.
8. Lesson summary and revision card
- I can link temperature to particle speed.
- I can explain diffusion.
- I can describe Brownian motion.
- I can compare states.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- Hotter means faster particles.
- Diffusion is faster when warmer.
- Gases diffuse fastest.
- Brownian motion supports the model.
11. Next lesson
Next lesson: Changes of state. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Define temperature and diffusion. [2 marks]
- Explain Brownian motion. [3 marks]
- Compare diffusion in three states. [3 marks]
- Safety rule. [2 marks]
Total: 10 marks.
Marking guide and model answers
- 1 each
- Pollen jiggles [1]; hit by particles [1]; evidence [1]
- Gas [1]; liquid [1]; solid [1]
- Any [1]; reason [1]
Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- What is temperature?
- What is kinetic energy?
- What is diffusion?
- Who saw jiggling?
- Hotter means?
- Why warm faster?
- Why gases fastest?
- Why Brownian?
- Run the test.
- Graph.
Homework
Describe how a smell from the kitchen reaches another room.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 1. What is temperature? | Hot or cold. | 1 |
| 2. What is kinetic energy? | Movement energy. | 1 |
| 3. What is diffusion? | Spreading. | 1 |
| 4. Who saw jiggling? | Brown. | 1 |
| 5. Hotter means? | Faster. | 1 |
| 6. Why warm faster? | More energy. | 1 |
| 7. Why gases fastest? | Free. | 1 |
| 8. Why Brownian? | Hits. | 1 |
| 9. Run the test. | Table. | 1 |
| 10. Graph. | Chart. | 1 |
| Total | 10 |
Independent practice answers. Level 1: 1 Hot or cold.; 2 Movement energy.; 3 Spreading.; 4 Brown.; 5 Faster.. Level 2: 1 More energy.; 2 Free.; 3 Hits.. Level 3: 1 Table.; 2 Chart.; 3 Sentence..
Quiz answers: 1 B, 2 C, 3 A, 4 B, 5 C, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 B, Challenge 2 C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Link temperature to particle speed | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Explain diffusion | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Describe Brownian motion | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Compare states | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: “Cold particles stop moving.” They still move.
- Explain another way: use real objects, pictures or actions first, then words.
- Show a simpler example: Explain particle movement.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child studies particle movement. You do not need to be an expert to help.
- Watch tea dye spread.
- Ask “Why faster in warm?”
- Mind spills.
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: link temperature to particle speed; explain diffusion; describe Brownian motion; compare states.
Prerequisite knowledge. Grade 5 ideas: states of matter, changes of state, mixtures and dissolving.
Materials. Clear cups, water, food colouring, timer. Low-resource options: use chalk or charcoal on a board or wall, drawings in the sand, and objects from the classroom instead of printed materials.
Preparation. Warm water.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Open a scent and ask, “How does it get across the room?”
Explanation (10 min). Teach particle movement.
Guided activity (10 min). Learners test.
Independent activity (10 min). Learners explain.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. What changes with temperature? Why?
Teacher explanation notes. Start with real objects and safe, hands-on observation. Then talk about what was seen, then draw and write. Always say “how do you know?”. Keep to the safety notes, and use local, safe materials.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and pictures, short sentences and a partner. Let learners point, show or draw instead of writing. Extension. Ask learners to find a new example at home and explain how they know.
Formative assessment. Listen to learners read and explain, ask “how do you know?”, and check the independent work.
Misconceptions. “Cold particles stop moving.” They still move.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz, the 10-mark exam practice and the worksheet on this page. All answers and marking guides are in the answer sections above. Re-check every answer before use.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Explain particle movement. Enrichment. Look for one new example near your home or school, draw it and explain it to someone. Homework. See above.
Teacher reflection. After teaching, record: which ideas learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points: Next Generation Science Standards, Cambridge Primary Science and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Research used to shape this lesson. Courseversity Science curriculum, Grade 6 Unit 5, topic 6; Next Generation Science Standards, structure and properties of matter; Cambridge Lower Secondary Science, chemistry; IB Primary Years Programme, how the world works. These sources informed the lesson.