Give reasons for the following.

Thermometer reading remains constant for a while during melting of a solid even though we continue to heat the solid.

When we supply heat to a solid, with the increase in temperature, the kinetic energy of particles in a solid also increases. The particles start vibrating at high speed about their fixed position. At a certain temperature, a moment arises when the energy supplied by heat overcomes the intermolecular force of attraction between the particles. The particles then break free and leave their fixed position and start moving freely. At this stage, the solid start melting and gets converted into a liquid. Though we continue supplying heat, the temperature doesn’t rise, and the thermometer reading remains constant. Because the heat supplied gets used up as latent heat to convert the solid into a liquid.