Explain the process of change in the state of matter by heating or cooling it.

(N/A) To understand the change in the state of matter,consider the heating curve of water.
$1$. Take some ice cubes in a beaker and note the initial temperature,which is $0^{\circ} C$.
$2$. Place the beaker on a constant heat source and start heating it slowly.
$3$. Continuously stir the mixture of ice and water to ensure uniform temperature distribution.
$4$. Note the temperature of the mixture at regular intervals (e.g.,every minute) and plot a graph of temperature versus time.
$5$. You will observe that the temperature remains constant at $0^{\circ} C$ as long as there is ice present in the beaker,even though heat is being continuously supplied.
$6$. This constant temperature phase occurs because the heat supplied is being utilized as latent heat of fusion to overcome the intermolecular forces of attraction,changing the state from solid (ice) to liquid (water).
$7$. Once all the ice has melted,the temperature of the water will begin to rise until it reaches the boiling point $(100^{\circ} C)$,where another phase change (liquid to gas) occurs at a constant temperature.