When a solid melts, its temperature remains constant because the heat energy added to the solid is used to change the state of the substance from solid to liquid, rather than increase the temperature of the solid. This phenomenon is known as latent heat.


There are two types of latent heat:

• Latent Heat of Fusion: This is the amount of heat energy required to change a solid into a liquid at its melting point.


• Latent Heat of Vaporization: This is the amount of heat energy required to change a liquid into a gas at its boiling point.

When a solid is heated, the heat energy is absorbed by the particles of the solid. As the temperature reaches the melting point, the heat energy is used to overcome the intermolecular forces between the particles of the solid, enabling them to move apart from each other. As the solid melts, the temperature remains constant as the heat energy is being used to break these intermolecular forces. Once all the particles have separated, the temperature of the liquid begins to rise again.


Examples of latent heat of fusion in everyday life include:

• Ice melting into water at 0°C


• Wax melting when heated


• Butter melting when heated

In conclusion, when a solid melts, the temperature remains constant as the heat energy is being used to break the intermolecular forces between the particles of the solid. This phenomenon is known as latent heat, and it is essential to understanding the behavior of matter in different states.

the heat energy is absorbed by the particles of matter to change their state.