Energy Stores and Conservation of Energy

Overview

This lesson gives you the language for the rest of the topic. Keep the difference between an energy store and an energy transfer pathway clear, because that distinction is what makes later work on work, power, and efficiency much easier.

What You Need to Know

• Introduce the main stores: kinetic, gravitational potential, chemical, elastic, nuclear, electrostatic, and internal.
• Compare transfer pathways such as mechanical work, electrical work, heating, and waves.
• Revisit conservation of energy as a system-level principle: energy is not lost, but it may become less useful because it is transferred to stores like the surroundings’ internal energy.
• Use simple flow diagrams first, then extend to multi-stage examples and Sankey diagrams.
• Keep the descriptions tied to real systems such as falling objects, stretched springs, or powered devices.

How to Work Through It

1. Start with a short prompt asking where the energy is stored in a familiar system such as a toy car, battery, or falling object.
2. Work through the store-and-transfer language using a small set of repeated examples.
3. Practise conservation questions with flow diagrams and then with simple Sankey diagrams.
4. Finish with short explanations where you must track energy through two or more stages.

Check Your Understanding

• Check whether you can identify whether a named item is an energy store or a transfer pathway.
• Use a hinge question where you choose the correct energy-store change in a given event.
• Try one simple Sankey or flow diagram and check whether you can explain where the energy ends up.

Common Mistakes

• Saying energy is “used up”. Keep conservation central and ask where the energy was transferred instead.
• Some mix up transfer pathways with stores, especially heating and internal energy. Keep both terms side by side in examples.
• Sankey diagrams can be read as just pictures unless you explain the meaning of each arrow.

Next Steps

• Set short store-and-transfer explanation tasks so the language becomes secure.
• Carry the idea of transferred energy into work and power.