Cambridge IGCSE Chemistry · Syllabus 0620 · States of Matter
Heating curve
What is Heating curve?
A graph of temperature against time for a substance that is being heated at a steady rate. For a pure substance at constant pressure it consists of sloping sections, where the temperature rises because the average kinetic energy of the particles is increasing, separated by horizontal sections called plateaus, where the temperature stays constant while a change of state takes place because the energy transferred is used to overcome the attractive forces between particles instead of increasing their average kinetic energy. The temperature of the first plateau is the melting point and the temperature of the second is the boiling point. A cooling curve is the same graph for a substance losing energy, with plateaus at the freezing point and the condensing temperature.
This definition is part of the States of Matter chapter in Cambridge IGCSE Chemistry.