Ocean in a Bottle

Waves of color.....

Here's What You Need:

*clear plastic bottle with cap

*water

*food coloring

*vegetable oil or baby oil

*masking tape

Here's What you Do:

Fill the bottle about 1/3 full with tap water.  Add some food coloring--blue to make "ocean waves."

Fill the rest of the bottle up with oil.  Screw the cap on securely and tape with masking tape.

Swirl the bottle and notice the results!  Give it a good shaking and the substances will seem to combine for awhile.

Why?

Water mixes with many things, but not oil!  When you put them together in the same container they remain separate.  This makes them insoluble.  If you shake the bottle they seem to combine for awhile, because the oil breaks up into tiny oil globs and is suspended in the water temporarily--in this state it is called an emulsion. As the bottle sits, the two substances completely separate again.  

Take it Further:

If you remove the masking tape and add a bit of sand to the bottle, it will sink to the bottom--because it has more density than the water or oil.  You can experiment by adding different material to the bottle and asking your child what they think will happen.  What happens if you add a styrofoam peanut? Will is sink or float--which is more dense? What about a rock?