Kitchen Chemistry Experiment 18
Red, White and Blue II

This colorful demonstration shows the rule "likes dissolve likes" by combining three immiscible (insoluble) liquids to create a density column.

Materials	Subsitutions
blue lamp oil	red lamp oil
whole milk
high sucrose syrup-clear	light corn syrup
red food coloring	blue food coloring
tall form 400 mL beaker	tall plastic or glass jar

Procedure

 

1. Wrap the outside of the glass loosely with aluminum foil so that you can pour your liquids into the glass and can uncover the glass easily by lifting the foil off.
2. Add several drops of red food coloring to the Karo Syrup and invert several times to mix.
3. Pour the three liquids -red colored syrup, milk, blue lamp oil- into the glass in any order. Pour slowly so that not too much mixing occurs.
4. Ask the students what color will result from mixing red, white, and blue. Then lift the aluminum foil mask to reveal three layers, with the red syrup on the bottom, white milk over the syrup, and blue lamp oil on top.

 

Teacher's Notes

Because the milk is not exposed to air, it will not spoil in the density column. Therefore, you can keep this demo for weeks. All substances can go down the drain with copious amounts of water for disposal.

Most dollar (dime) stores (like Walmart or K-Mart) will carry lamp oil. The colors available often depend on the season. You can color your syrup differently to adjust for the color of the lamp oil that is available.

Immiscible liquids don't mix because of differing densities, molecular polarities, or both. The lamp oil has a density < 1 g/mL and is a nonpolar molecule. The milk has polar and nonpolar characteristics but since 80% of milk is water, it is mostly polar. The syrup has very little water in it and has a density of 1.37 g/mL.