Oil & Water

• Fill the glass jar 1/3 full with oil

• Add an equal amount of water to the jar of oil (beforehand, make predictions!)... observe what happens when the water is added to the oil.

• Once the liquids settle, again make predictions before adding a few drops of food coloring on top of the oil, and then observe what happens. (Does it mix with the oil? Does it stay on top? Does the oil change colors? Note: If the food coloring cannot make its way through the oil, you can use the toothpick/stir stick to poke a hole in oil so the color can sink).

• Once the food coloring sinks into the water layer, observe what happens.  Can food coloring mix with water?  You can give the mixture a stir and again observe what happens.

• This can be repeated experimentally with different color mixtures, different shaped containers, different proportions of oil & water, etc!

• Glass jar/container(s)

• Food coloring

• Vegetable oil (any variety)

• Water

• Stirring stick

This is a simple experiment that demonstrates the different density of liquids.  Water is more dense than oil.  This experiment can be repeated and extended in various ways to explore these concepts for different ages and focuses.

The oil will separate and rise in a layer on top of the water because water is more dense (thus sinking to a layer underneath).  When the water-based food coloring is added, it is also more dense and can sink through the oil layer into the water beneath.  The food coloring will not mix with the oil, but will mix when it enters the water layer.