The heat which is going into ice but not increasing its temperature, is the energy required to change the state of ice from solid to liquid (water). This is known as the latent heat of fusion of ice (or latent heat of melting of ice). The latent heat of fusion of ice is 3.34 × 105 J/ kg (or 3.34 × 105 j/kg). Hence 3.34 x 10 5 J of heat has to be supplied to change 1 Kg of ice (at its melting point, 0 C) into water at the same temperature of 0C.