Operation: Lava Lamp

Lava Lamp

What I did:

I used vegetable oil and salt and food coloring and water. First I put water in an empty 2L bottle and then I put food coloring in it. Then I put in oil and then I put in salt. It made a big bubble that went up and down.

What I learned:

Water and oil don't mix - oil goes on top (it's lighter than water).
Salt is heavier than water and makes the oil sink.
The salt dissolved and the oil went back up (floats).

It is fun watching the salt pile onto the oil and then sink.

It is fun watching the bubbles. "Oooh! Aaah!"