By the end of this activity you will be able to: Identify the effects of mixing materials with water.

When we make changes to materials by dissolving them in water we can sometimes reverse the change. For example, adding salt to water can be reversed by evaporation. Some materials react with water (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 the water 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.

What will happen to each of these materials when you mix them with water?