Question

Describe an experiment to show that there is an absorption of heat energy when the ice melts.

Answer 1

First of all ice is taken, at temperature $0^{o}C$. Heat the ice at constant rate and temperature is measured. The temperature will remain $0^{o}C$ until all the ice melts. Melting of ice takes all the heat energy input and temperature remains constant. The temperature starts to rise again if all the ice has melted. This is called latent heat of fusion.

Get some ice from fridge and heat it gently in the flask. Wait for the ice to start melting. At that stage ice and water will be in equilibrium at a zero degree celcius. Put a thermometer in water and continue heating. There will not be any rise in temperature until all the ice has melted. After all ice has melted there is rise in temperature. This shows that ice absorbs heat when it melts.