Latent Heat

What is Latent Heat?

The energy absorbed or released when a substance changes phase — melting, freezing, boiling or condensing — without any change in temperature. It's why boiling water stubbornly stays at 100°C no matter how hard it's heated: every joule going in converts liquid to vapour instead of raising the temperature further.

The five clues

Engineerdle #14 described Latent Heat with five clues, revealed one at a time from hardest to most direct. Each clue points at a different property of the concept.

1. 01Heat that goes in without raising the temperature at all.
2. 02It's absorbed or released during a change of phase, not a change of state within one phase.
3. 03It's why a pot of boiling water stays at 100°C no matter how high you turn the flame.
4. 04Melting and vaporising each require a different amount of it.
5. 05The energy absorbed or released during a phase change at constant temperature.

More Thermodynamics concepts

• Triple PointPuzzle #52
• Isentropic ProcessPuzzle #44
• EntropyPuzzle #39
• Adiabatic ProcessPuzzle #34
• Specific Heat CapacityPuzzle #9
• First Law of ThermodynamicsPuzzle #4