Ice and water

On a bright summer afternoon, Aavi and Thirav are enjoying shikanji (lemonade). Looking at the ice in it, Thirav wonders about ice and water, and Aavi has a different view. Are ice and water different substances? Ice is hard and you can hold it in your hand; you cannot hold water like that.

Try it: put an ice cube in a cup, leave it on the table and watch. The ice turns into water.

So ice and water are two forms of the same substance. These forms are called states. ('State' here does not mean a state like Kerala; it means the form something is in.)

The states of water behave differently. Water flows; ice does not. Water splashes; ice does not.