Latent Heat
Latent heat is the energy absorbed or released during a change of state without any change in temperature.
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Latent heat is the energy absorbed or released during a change of state without any change in temperature.
- Energy breaks or forms bonds between particles
- Specific latent heat is energy per kilogram
- Sweating cools you through evaporation
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Latent Heat?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Latent Heat. 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 Latent Heat in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Latent Heat explains how the physical world behaves, from sport and transport to electricity and medicine.
Latent Heat in detail
Latent heat is the energy absorbed or released when a substance changes state at constant temperature. Specific latent heat is the energy needed to change the state of 1 kg: E = mL. There are two types: latent heat of fusion for melting and latent heat of vaporisation for boiling.
The energy goes into overcoming the forces between particles rather than raising temperature. The latent heat of vaporisation of water, about 2.26 million J/kg, is much larger than that of fusion because particles must be fully separated. This explains why steam burns badly and why sweating cools the body.
How the interactive helps you understand Latent Heat
Watch the gas particle model in the interactive. Use any sliders or buttons it offers to change the values and see how the gas particle model 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 Latent Heat.
Real-life uses and examples
- Explain everyday devices, such as brakes, lifts or chargers, using Latent Heat.
- Use Latent Heat to make sense of a practical and its results.
- Answer “explain” questions by linking Latent Heat to a clear cause and effect.
Common mistakes to avoid
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Mixing up Latent Heat with a related quantity that has different units.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Latent Heat
What is Latent Heat?
Latent heat is the energy absorbed or released during a change of state without any change in temperature.
What are the most important points about Latent Heat?
The main points are: Energy breaks or forms bonds between particles; Specific latent heat is energy per kilogram; Sweating cools you through evaporation.
Why is Latent Heat useful?
Understanding Latent Heat explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Latent Heat?
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 Latent Heat?
Related topics in Physics include Thermal Radiation, Waves: Basic Properties, Reflection of Waves.