In this video, TalkingScience’s own kitchen chemists demonstrate the effects of density by making their own lava lamp.

Materials:
A glass
½ cup water
1/3 oil
Food coloring
Table salt

Do it yourself:
1. Pour ½ cup of water into a glass
2. Add 1/3 cup of oil to the glass
3. Add a couple drops of food coloring
4. Shake salt on top of the oil while you count slowly to 10
5. Watch science in action!

What’s happening:
Because salt is more dense than water, when you add it to your mixture, it sinks. Blobs of oil attach to the sinking salt grains and are dragged down to the bottom of the glass. When the salt dissolves, the oil drops rise again to the surface of your mixture, because oil is lighter, or less dense, than water.

Check out another Kitchen Chemist video:
Magic Milk