--- title: "Moving or stored?" subtitle: "Year 8 Physics · Energy transfer and transformation · Lesson 1" --- # Moving or stored? **Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}} > **Key question:** A roller coaster has no engine after the first climb. Yet it races down, swoops up the next hill and keeps going for a minute or more. Where does its energy come from? :::teacher-note **In one sentence:** Students classify energy as kinetic (activity: movement, heat, sound, light, electrical) or potential (stored: chemical, gravitational, elastic), with examples, and see the two change into each other (AC9S8U05, nodes 1 and 2). **Students should be able to say:** I can sort energy into kinetic and potential. I can give examples of chemical, gravitational and elastic potential energy. I can say what decides how much energy is stored. **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 :::keep-together **A heavy book sits still on a high shelf. Does it have any energy?** ☐ Yes: stored energy, because it is high up and could fall ☐ No: energy is only in living things ☐ Only if someone pushes it ☐ No: it isn't moving My prediction, and why: {{lines-3}} ::: :::teacher-note **What happens:** Yes. It has gravitational potential energy, stored because it is high up. Knock it off and that stored energy becomes kinetic energy as it falls. ::: ## Explore Try it on the board in the tutorial. Was your prediction right? What was different? {{lines-2}} ## Explain: two families :::keep-together ### Sort them **Kinetic (active) or potential (stored)?** Groups: Kinetic, Potential - A rolling ball: {{field-15}} - The heat from a heater: {{field-15}} - Music from a speaker: {{field-15}} - Light from a torch: {{field-15}} - Food in your lunchbox: {{field-15}} - A stretched rubber band: {{field-15}} - A charged battery: {{field-15}} - A diver on a high board: {{field-15}} ::: :::teacher-note **Answer:** A rolling ball → Kinetic; The heat from a heater → Kinetic; Music from a speaker → Kinetic; Light from a torch → Kinetic; Food in your lunchbox → Potential; A stretched rubber band → Potential; A charged battery → Potential; A diver on a high board → Potential ::: :::keep-together ### Fastest point **On the coaster, where is the kinetic energy greatest?** ☐ At the bottom of the deepest dip, where the car is fastest ☐ It stays the same everywhere ☐ At the top of the first hill ::: :::teacher-note **Answer:** At the bottom of the deepest dip, where the car is fastest Lowest point, least potential energy, so the most kinetic energy: the car is fastest there. ::: :::keep-together ### How much is stored **What decides how much gravitational potential energy something has?** ☐ How fast it is moving ☐ How heavy it is and how high it is ☐ What colour it is ::: :::teacher-note **Answer:** How heavy it is and how high it is Heavier and higher means more stored. Likewise, stretching a spring further stores more elastic energy, and different foods store different amounts of chemical energy. ::: :::keep-together ### Active or stored **What do all kinds of kinetic energy have in common, and how is potential energy different?** ☐ Kinetic energy is active now (something moving, vibrating or flowing); potential energy is stored, ready to be released ☐ Kinetic energy is useful; potential energy is wasted ☐ Potential energy is energy that might exist one day but doesn't yet ☐ Kinetic energy is only in moving objects; heat, light and sound aren't kinetic ::: :::teacher-note **Answer:** Kinetic energy is active now (something moving, vibrating or flowing); potential energy is stored, ready to be released Ask 'is it active now, or stored?' Active (moving, vibrating, flowing) is kinetic; stored and ready to be released is potential. ::: :::typical ## Elaborate: a higher hill :::keep-together ### What changed **Compared with the 30 m start, what is different?** ☐ The same total energy ☐ More total energy, so the car goes faster at the bottom ☐ Less kinetic energy at the bottom ::: :::teacher-note **Answer:** More total energy, so the car goes faster at the bottom More height, more gravitational potential energy, more kinetic energy when it comes down. ::: ::: :::wider ## Elaborate: trampolines and bows :::keep-together **On a trampoline you land, sink down, and spring back up. Which energy is stored at the lowest point?** ☐ Elastic potential energy, in the stretched trampoline ☐ Kinetic energy, because you're moving fast ☐ No energy: you've stopped for an instant ::: :::teacher-note **Answer:** Elastic potential energy, in the stretched trampoline Kinetic → elastic potential as the mat stretches, then back to kinetic and up to gravitational potential as you rise. ::: ::: ## Evaluate: look back Write one sentence: "At first I thought… Now I think… because…" **Revision summary** - **Kinetic energy** is energy of activity: movement, heat (thermal), sound, light, electrical. - **Potential energy** is stored: chemical (food, fuel, batteries), gravitational (height), elastic (stretched or squashed). - How much is stored depends on height and mass, how far something is stretched, or what a substance is made of. - Energy changes between kinetic and potential, as on a roller coaster. The total stays the same. ## Exit ticket :::keep-together **Name one example each of chemical, gravitational and elastic potential energy.** {{lines-3}} ::: :::teacher-note **Answer:** For example: a battery or food (chemical), a ball held up high (gravitational), a stretched slingshot (elastic). :::