The particles of the particle model are atoms. Atoms come in different types, one type for each element, and atom type decides what element a substance is.
Water, oxygen and carbon dioxide are all made of particles. So why is one a drink, one keeps you alive, and one puts out fires?
In Year 7 every particle was just "a particle". This lesson gives them an identity.
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: are all particles the same?
Decide before you look.
ExploreTry it on the board and compare what happens with your prediction.
Explore: zoom into air
Click a particle (or press Inspect next particle) to see what it is made of. Find every kind. Notice the coloured balls: each colour is one type of atom.
Try it yourselfNothing is saved: start again as often as you like.
Inspect every kind of particle in the air.
Use the board. This ticks when you get there.
ExplainUse the particle model to explain what you saw.
Explain: atoms and elements
In your book, finish this sentence in two or three lines: "The particles in the particle model are… Different elements are different because…"
True or false?
All the atoms in a sample of pure oxygen are the same type
An element is made of only one type of atom
There are about 118 types of atom
An oxygen atom in water is a different type from an oxygen atom in airAn oxygen atom is an oxygen atom, wherever it is.
Atoms are coloured like the balls on the boardAtoms have no colour. The colours are a code.
Atoms are the smallest piece of an element that is still that element
Elaborate TypicalUse the same idea in a new context.
Elaborate: which gases are elements?
Try it yourselfNothing is saved: start again as often as you like.
Inspect all four gases.
Use the board. This ticks when you get there.
How is each element's particle made?
Helium
Neon
Oxygen
Nitrogen
Elaborate WiderUse the same idea in a new context.
Elaborate: how the idea of atoms grew
Put the ideas about matter in the order they were proposed, earliest first.
Pieces (click to add)
Your program
EvaluateLook back at your first ideas and what changed.
Evaluate: look back
What did you think air was made of? Write one sentence: "At first I thought… Now I think… because…"
Revision summary
The particles in the particle model are atoms (or atoms joined together).
There are about 118 types of atom, one for each element.
All atoms of one element are the same type. Atom type decides the element.
An element can be single atoms (helium) or atoms of one type joined (oxygen, O₂).
For teachers
Students extend the particle model so that particles are atoms with a type, and explain that atom type decides the element (AC9S8U06, node 1, a hinge node). About 20 minutes.
I can explain that the particles in the particle model are atoms.
I can explain that different elements are made of different types of atom.
I can explain that atom type decides what element a substance is.
Before class
A concept tutorial for introducing or revising the idea; it does not replace models, kits or class discussion. Set the width with ?width=minimum, typical (default) or wider.
Frame it as an upgrade, not a replacement: "you know particles exist; now we add that particles have a type". The hinge risk is students carrying identical particles into compounds (node 3) and chemical change.
Running the lesson
Engage: count how many chose identical particles. That is the Year 7 picture the board upgrades.
Explore: students should find all five kinds in air (nitrogen, oxygen, argon, carbon dioxide, water). Ask which colours appear in more than one kind of particle.
Explain: the two questions carry the checkpoint. The sort catches 'atoms have colours' and 'oxygen in water is different'.
In your own words: collect the sentence; it is the node's checkpoint in the student's words.
The hard part (on purpose)
Seeing particles as built from atoms, and atom type as what makes an element. When a student calls O₂ a compound, ask how many types of atom are in it.
When students get stuck
A student says the atoms are red and white. Ask: Is water red and white? Is air? Fix: The colours are a code, like a map key. Real atoms have no colour.
A student says O₂ is a compound because it has two atoms. Ask: How many types of atom are in it? Fix: One type, so it is an element. A compound needs different types joined.
A student thinks the particles of air float in air. Ask: What is between the particles on the board? Fix: Nothing at all. The particles are the air.
Stretch and support
Stretch: Carbon dioxide and carbon monoxide are both made of carbon and oxygen atoms, yet one is in your breath and the other is deadly. What could be different about them?
Support: Before Explore, give a key card: one coloured dot for each element on the board, with its name, to tick as students find it.
Where it leads
Next: node 3, compounds (different atom types chemically joined), with the formula notation that goes with them.
In class: ball-and-stick or modelling-clay atoms in different colours; build O₂, N₂, H₂O and CO₂ and sort them into elements and compounds.
What each step is for
Engage: are all particles the same?: Students carrying the Year 7 picture of identical particles will say yes; the board shows particles built from different atoms.
Explore: zoom into air: Inspecting each kind of particle in air makes 'particles have type' visible before it is named.
Explain: atoms and elements: Naming the upgrade explicitly (the particles you know are atoms, and atoms have type) is the hinge: elements and compounds both depend on it.
Elaborate: which gases are elements?: Single atoms and two-atom molecules can both be elements: the test is one atom type, not one atom.
Elaborate: how the idea of atoms grew: Ordering the models shows the atom as a model refined by evidence, which prepares Year 9 (atoms have parts inside).
Now you can
Explain that the particles in the particle model are atoms.
Explain that different elements are made of different types of atom.
Explain that atom type decides what element a substance is.