--- title: "What is everything made of?" subtitle: "Year 7 Chemistry · Particle theory · Lesson 1" --- # What is everything made of? **Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}} > **Key question:** Water looks smooth and continuous. Zoom in about a billion times and the picture changes completely: that picture is the particle model, and the rest of chemistry is built on it. :::teacher-note **In one sentence:** Students build the particle model's four key ideas (particles, space, motion, attraction) and match particle diagrams to solids, liquids and gases (AC9S7U05, node 1, a hinge node). **Students should be able to say:** I can state the four key ideas of particle theory. I can match a particle diagram to a solid, a liquid or a gas. I can describe how arrangement and motion differ between the three states. **Width:** the unmarked parts are the floor every student does (Engage, Explore, Explain, Evaluate). Typical and Wider sections add contexts, not difficulty. Students work in the online tutorial alongside this sheet. ::: ## Engage Decide before you look. There is no penalty for being wrong: the point is to find out what you think now. :::keep-together **Zoom into a drop of water a billion times. What would you see?** ☐ Tiny particles with empty space between them ☐ Smooth water, all the way down ☐ Tiny particles floating in water ☐ Lots of tiny drops of water My prediction, and why: {{lines-3}} ::: :::teacher-note **What happens:** Tiny particles with empty space between them, always moving. There is nothing between them, not even air. ::: ## Explore Try it on the board in the tutorial. Was your prediction right? What was different? {{lines-2}} ## Explain: what the model says :::keep-together ### Between the particles **What is between the particles?** ☐ Air ☐ Water ☐ Nothing: empty space ::: :::teacher-note **Answer:** Nothing: empty space There is nothing between particles, not even air. ::: :::keep-together ### Ice **Do the particles in ice ever stop moving?** ☐ Yes, ice is frozen still ☐ No, they vibrate in place ::: :::teacher-note **Answer:** No, they vibrate in place Even in a solid, particles vibrate. They never stop. ::: :::keep-together ### Same particles? **Ice, liquid water and steam: are their particles the same?** ☐ No: steam particles are smaller ☐ No: ice particles are bigger ☐ Yes: only the arrangement and motion change ::: :::teacher-note **Answer:** Yes: only the arrangement and motion change All three are made of the same water particles. ::: :::keep-together ### The four key ideas **Which statements are part of particle theory?** Groups: Part of particle theory, Not true - All matter is made of tiny particles.: {{field-15}} - There is empty space between particles.: {{field-15}} - Particles are always moving.: {{field-15}} - Particles attract each other.: {{field-15}} - Particles expand when they are heated.: {{field-15}} - There is air between the particles.: {{field-15}} - Particles in a solid do not move.: {{field-15}} ::: :::teacher-note **Answer:** All matter is made of tiny particles. → Part of particle theory; There is empty space between particles. → Part of particle theory; Particles are always moving. → Part of particle theory; Particles attract each other. → Part of particle theory; Particles expand when they are heated. → Not true; There is air between the particles. → Not true; Particles in a solid do not move. → Not true Remember the four key ideas as: particles, space, motion, attraction. ::: :::keep-together ### Across the states **Match each state to its particles: arrangement, motion and attraction.** A. Far apart, moving fast in all directions, very weak attraction B. Close together in a fixed pattern, vibrating in place, strong attraction C. Close together with no pattern, sliding past each other, weaker attraction {{columns 60% 40%}} {{rows 1}} | Part | Letter | |---|---| | `Solid` | | | `Liquid` | | | `Gas` | | ::: :::teacher-note **Answer:** Solid → B. Close together in a fixed pattern, vibrating in place, strong attraction; Liquid → C. Close together with no pattern, sliding past each other, weaker attraction; Gas → A. Far apart, moving fast in all directions, very weak attraction The three states differ in the same three ways: arrangement, motion and attraction. ::: ## name that state Each round shows a new substance through the zoom lens. Is it a solid, a liquid or a gas? :::typical ## Elaborate: explain three things about ice On paper: draw a particle diagram of ice and label it with these three explanations. :::keep-together **For each property of ice, choose the particle explanation.** Groups: Its particles are held in fixed positions by strong attraction, Its particles are packed closely, with very little space between them, Its particles vibrate more as they warm, until they break free of their positions, Its particles are far apart and move freely, Its particles get bigger when warmed - Ice keeps its shape on a plate.: {{field-15}} - You can't squash an ice cube.: {{field-15}} - An ice cube held in your hand starts to melt.: {{field-15}} ::: :::teacher-note **Answer:** Ice keeps its shape on a plate. → Its particles are held in fixed positions by strong attraction; You can't squash an ice cube. → Its particles are packed closely, with very little space between them; An ice cube held in your hand starts to melt. → Its particles vibrate more as they warm, until they break free of their positions Each property comes from one particle feature: arrangement, motion or attraction. ::: ::: :::wider ## Elaborate: build a state Choose how close the particles are and how they move. Try the combinations that don't make a real state too, and read what the board says. ::: :::wider ## Elaborate: how good is the model? :::keep-together ### What it explains **Does the particle model explain it?** Groups: Explained by the model, Not explained - Why a gas spreads to fill its container: {{field-15}} - Why you can smell perfume from across a room: {{field-15}} - Why copper is orange-brown: {{field-15}} - Why solids keep their shape: {{field-15}} - What particles themselves are made of: {{field-15}} - Why some substances are poisonous: {{field-15}} ::: :::teacher-note **Answer:** Why a gas spreads to fill its container → Explained by the model; Why you can smell perfume from across a room → Explained by the model; Why copper is orange-brown → Not explained; Why solids keep their shape → Explained by the model; What particles themselves are made of → Not explained; Why some substances are poisonous → Not explained The model explains how substances behave, not everything about them. ::: :::keep-together ### The evidence **In 1827 the botanist Robert Brown saw tiny grains from pollen jiggling in water under a microscope, in random directions, with nothing stirring the water. In 1905 Albert Einstein explained it with particles. What causes the jiggling?** ☐ The grains are alive and swimming ☐ The water is flowing slowly ☐ Water particles are always moving and keep bumping into the grains ::: :::teacher-note **Answer:** Water particles are always moving and keep bumping into the grains This is Brownian motion: millions of tiny bumps from moving water particles. It was early strong evidence that particles are real and always moving. ::: ::: :::wider ## Elaborate: designing with materials :::keep-together **Match each design choice to the particle reason.** Groups: A gas can be squashed, so it cushions bumps, A liquid hardly squashes, so a push at one end moves the other end straight away, Solid particles are held in fixed positions, so the shape stays under a load, Its particles are lighter - Bike tyres are filled with air, not water.: {{field-15}} - Car brakes use a liquid in the pipes to push the brake pads.: {{field-15}} - Bridge beams are made of solid steel.: {{field-15}} ::: :::teacher-note **Answer:** Bike tyres are filled with air, not water. → A gas can be squashed, so it cushions bumps; Car brakes use a liquid in the pipes to push the brake pads. → A liquid hardly squashes, so a push at one end moves the other end straight away; Bridge beams are made of solid steel. → Solid particles are held in fixed positions, so the shape stays under a load ::: ::: ## Evaluate: look back Go back to your prediction in Engage. Was matter smooth, drops, particles in water, or particles with empty space? Write one sentence: "At first I thought… Now I think… because…" **Revision summary** - All matter is made of tiny particles; there is empty space between them; they are always moving; they attract each other. - **Solid:** close together in a fixed pattern, vibrating in place. - **Liquid:** close together with no pattern, sliding past each other. - **Gas:** far apart, moving fast in all directions. - There is nothing between particles: not air, not water. ## Exit ticket :::keep-together **Name the four key ideas of particle theory.** {{lines-3}} ::: :::teacher-note **Answer:** All matter is made of particles; there is empty space between them; they are always moving; they attract each other. :::