Cauldron Bubbles

What you will need:


Clear glasses
water
oil
salt
sugar
sand

You can make different objects fall and rise in water. You can do this with bubbles of oil too!
Directions:

Fill a glass half full of water.
Add about a half-inch of oil. The oil will float on top because it is less dense than the water.
Pour in some salt. What do you see?
When you pour in the salt, it brings a bubble of oil down with it. The salt and the oil together are more dense than the water, so they sink. When the salt dissolves in the water, the oil floats back to the top because now it is less dense than the water.
See if you can make cauldron bubbles with different materials. Try sugar and sand.

Make predictions about what you think will happen with each different material.