Conservation of Energy
Energy cannot be created or destroyed, only transferred from one form to another, so the total stays constant.
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Energy cannot be created or destroyed, only transferred from one form to another, so the total stays constant.
- Energy is transferred in a system
- Some always dissipates as heat
- Sankey diagrams show the flow
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Conservation of Energy?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Conservation of Energy. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Conservation of Energy in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Conservation of Energy explains how the physical world behaves, from sport and transport to electricity and medicine.
Conservation of Energy in detail
The principle of conservation of energy states that energy cannot be created or destroyed, only transferred from one store to another or dissipated to the surroundings. The total energy before an event equals the total after, even if some ends up as less useful thermal energy.
Sankey diagrams show how energy splits among useful output and waste. Using conservation of energy, you can solve problems without knowing the details of the forces, such as the speed of a pendulum at its lowest point. It is one of the most fundamental laws in all of science.
How the interactive helps you understand Conservation of Energy
Watch the energy stores in the interactive. Use any sliders or buttons it offers to change the values and see how the energy stores responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Conservation of Energy.
Real-life uses and examples
- Use Conservation of Energy to make sense of a practical and its results.
- Answer “explain” questions by linking Conservation of Energy to a clear cause and effect.
- Predict what a ball, car or circuit will do with Conservation of Energy before you do the calculation.
Common mistakes to avoid
- Mixing up Conservation of Energy with a related quantity that has different units.
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Conservation of Energy
What is Conservation of Energy?
Energy cannot be created or destroyed, only transferred from one form to another, so the total stays constant.
What are the most important points about Conservation of Energy?
The main points are: Energy is transferred in a system; Some always dissipates as heat; Sankey diagrams show the flow.
Why is Conservation of Energy useful?
Understanding Conservation of Energy explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Conservation of Energy?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Conservation of Energy?
Related topics in Physics include Energy Resources, Conservation of Momentum, Gravitation.