Question

What happens when we mix cornstarch and iron fillings??

Answer 1

When we make changes to materials by dissolving them in water or another liquid we can sometimes reverse the change. For example, adding salt to water can be reversed by evaporation. Some materials react with a certain liquid (chemical reaction) to make a new material. For example, a new material (concrete) is made by mixing cement with water. You cannot get the cement back once it has been mixed with the water. Other solids may react with a liquid to produce a gas which escapes as bubbles.

If we can change the material back it is called a reversible change, if we cannot change the material back it is called an irreversible change