We will use balls of modeling clay to simulate the difference between mixtures and compounds.

1.  Make 10 small balls of blue modeling clay and 10 small balls of yellow modeling clay.

2.  Place 5 blue and 5 yellow balls into a glass container.

This represents a mixture.

3.  Now take 5 blue and 5 yellow balls, mix them together and place them in a glass container.

This represents a compound.