You need to have JavaScript enabled to view this video clip.


An explanation of latent heat energy. When substances change state, they either give out or take in heat energy. For a pure substance, the temperature of boiling or melting takes place at a constant temperature.
This clip is from:
First broadcast:
20 March 2008

Classroom Ideas

The clip can form part of lessons on energy transfer. Explain the concept of latent heat to the class and discuss why water boils at a constant temperature and why this in turn ensures that the eggs cook at the same rate. After watching the clip, students should recognise that a change of state does not involve a change of temperature and that energy is gained or lost by a substance when its state is changed.

This clip also features in: