Mixtures are very important to our lives. We use mixtures for many things. A mixture is one of the ways we combine materials.

Making a mixture is a physical change. No chemical reaction takes place between the materials in a mixture.

• Mixtures such as gravel are called heterogeneous^* mixtures.
• They are not the same throughout.
• They are not dissolved.

One special type of mixture is the solution. Solutions can be used to grow crystals. Mixtures behave differently in space because of a lack of sedimentation in orbit.