Pour slowly so that not too much mixing occurs. 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.
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.