Crystallisation

Crystallization is like making candy! When you mix sugar with water and heat it up, you can create a liquid that is super sweet. But if you let it cool down, the sugar molecules will start sticking together and form crystals. These crystals will continue to grow until they take up all the space in the container.

The same thing happens with other substances too, like salt or rocks. When you dissolve salt in water and then let the water evaporate, the salt crystals will start to form. This is because the salt molecules really like to stick together, and as the water goes away, they find each other more easily.

People use crystallization to make all kinds of things. They can purify substances by dissolving them in a liquid and then letting them crystallize out. They can also use it to separate different compounds from each other, because different substances will form different types of crystals.

Overall, crystallization is just a fancy term for when molecules stick together and form a solid shape. It's like making your own little candy or rock formations!