Conduction passes energy from particle to particle by collisions, with the particles staying in place. Convection carries energy as the heated fluid itself moves. The particle model explains both, and why metals conduct and trapped air insulates.
Leave a metal spoon in hot soup and the handle soon burns your fingers. Heat a pot of water from the bottom and the top gets hot too. Two different journeys for the energy.
In Year 7 you used the particle model to explain solids, liquids and gases. This lesson uses it to explain how energy moves.
Engage: Commit to a prediction before you test anything. A wrong guess is fine: it shows you what to look for.
Explore: Try it on the board and compare what happens with your prediction.
Explain: Use the particle model to explain what you saw.
Elaborate: Use the same idea in a new context.
Evaluate: Look back at your first ideas and what changed.
WidthMore contexts, same idea.
Make your prediction first. Help opens once you've locked it in.
EngageCommit to a prediction before you test anything. A wrong guess is fine: it shows you what to look for.
Engage: the spoon
ExploreTry it on the board and compare what happens with your prediction.
Explore: a heated bar, then heated water
Blue is cool, red is hot. Watch one particle: does it go anywhere?
Follow the ringed particle (or click another).
Try it yourselfNothing is saved: start again as often as you like.
Heat the bar until the far end warms up.
Use the board. This ticks when you get there.
Follow a particle round one loop in the heated water.
Use the board. This ticks when you get there.
ExplainUse the particle model to explain what you saw.
Explain: two ways to travel
In your book: explain the difference between conduction and convection. For each, say what the particles do.
Conduction or convection?
A saucepan handle getting hot
Warm air from a heater spreading round a room
Your hand warming up on a hot mug
Water in a kettle heating all the way through
A sea breeze on a hot afternoonAir over the warm land rises; cooler air from over the sea moves in.
Ice cream melting on a metal spoon faster than on a plastic one
Elaborate TypicalUse the same idea in a new context.
Elaborate: turn the heat off
Try it yourselfNothing is saved: start again as often as you like.
Elaborate WiderUse the same idea in a new context.
Elaborate: conductors and insulators
Elaborate TypicalUse the same idea in a new context.
Elaborate: a question to test
Scientists turn an idea from a model into something they can test. Here the idea is the trapped air from the last step: how would you test it with a cup of hot water, a thermometer and some wool?
EvaluateLook back at your first ideas and what changed.
Evaluate: look back
Write one sentence: "At first I thought… Now I think… because…"
Revision summary
Conduction: particles vibrate harder and pass energy to their neighbours by collisions. The particles stay in place. Mostly in solids; metals conduct well.
Convection: heated fluid becomes less dense and rises, cooler fluid sinks: a convection current. The particles move, carrying the energy. Only in liquids and gases.
Insulators (wood, plastic, trapped air) pass energy on poorly. Trapped air blocks convection too.
It is the hot fluid that rises, not "heat".
For teachers
Students explain conduction (energy passed by particle collisions, particles staying in place) and convection (the heated fluid itself moving, driven by density differences), and apply them to conductors and insulators (AC9S9U04, node 1). About 26 minutes.
I can explain conduction as energy passed between particles by collisions.
I can explain convection as the movement of heated fluid, driven by density differences.
I can explain why a named material is a good conductor or a good insulator.
Before class
A concept tutorial for introducing or revising the idea; it does not replace practical work. Set the width with ?width=minimum, typical (default) or wider.
The key contrast: in conduction, energy moves and particles don't; in convection, the particles carry the energy. Keep asking "what did one particle do?".
Assumed: density from Year 7 (Properties: fewer particles in each cm³, less dense). The "Why it rises" question links it to convection and names the model's shortcut.
Model note: in the simulation hot particles are pushed up directly; real hot fluid rises because its particles spread out (less dense). The wider step mentions possum-skin cloaks of south-eastern Australia; for richer context, use local resources and community guidance about First Nations clothing and bedding in your region.
Running the lesson
Engage: ask who chose 'hot particles travel up the handle'. The bar answers it.
Explore: on the bar, point to one particle for a few seconds. On the beaker, follow the ring the whole way round.
Explain: the first two questions are the core; the sort applies them; 'why not in a solid' links back to Year 7 particle theory.
In your own words: the comparison paragraph is the evidence for the node.
The hard part (on purpose)
Seeing energy move while the particles stay put. When a student says particles travel along the bar, ask them to watch one particle in the middle for ten seconds.
When students get stuck
A student says heat rises. Ask: On the board, what moved up? Fix: Hot water, because it is less dense. Heat itself spreads in every direction (the bar conducted sideways).
A student says particles move along the bar. Ask: Watch one particle in the middle for ten seconds. Where does it go? Fix: Nowhere: it vibrates in place. Only the energy travels.
A student says a metal bench is colder than a wooden one. Ask: If both have been in the same room all day, what temperature are they? Fix: The same. Metal feels colder because it conducts energy away from your hand faster.
Stretch and support
Stretch: Why is a heater usually placed low in a room and an air-conditioner high up?
Support: Give a two-column table (conduction, convection) with rows: what moves, which states, an example.
Where it leads
Next: the wave model of energy transfer: sound (node 2), then light and radiation (node 4).
In class: wax-stuck pins along metal and wooden rods heated at one end; a convection tube or a beaker with potassium permanganate crystals heated at one side.
What each step is for
Engage: the spoon: Students who picture particles travelling up the spoon will choose that option; the bar shows energy moving while the particles stay put.
Explore: a heated bar, then heated water: The same particle colours in a solid and a liquid make the contrast clear: in the bar energy moves and particles don't; in the water both do.
Explain: two ways to travel: Naming the mechanism in each case (collisions passing energy; the fluid itself moving) is what makes the terms explanations, not labels.
Elaborate: turn the heat off: Removing the heat source shows the current depends on a temperature difference: it slows and stops as the water evens out.
Elaborate: conductors and insulators: Explaining insulators with both mechanisms (poor conduction, trapped air that can't convect) applies the model to real materials.
Elaborate: a question to test: Turning the trapped-air idea into an investigable question and a reasoned hypothesis uses the model to plan a test, not just explain one.
Now you can
Explain conduction as energy passed between particles by collisions.
Explain convection as the movement of heated fluid, driven by density differences.
Explain why a named material is a good conductor or a good insulator.