Weird Science: Making your own rainbow

(HawaiiNewsNow) - This morning, Dr. V is helping us make our own rainbows.

Things you need:

  • Tall clear glass or plastic cup
  • ¼ cup corn syrup or honey
  • ¼ cup dishwashing liquid
  • ¼ cup water
  • ¼ cup vegetable oil
  • ¼ cup rubbing alcohol
  • Food coloring
  • Spoon to mix with

The Experiment:

Add different colors of food coloring to the corn syrup, dishwashing liquid (if clear), water and rubbing alcohol. Then pour them in the order as shown above, from top to bottom, into your cup. You will need to pour them slowly into the cup to get clean layers. You could try touching the tip of a spoon to the glass just above the last layer you poured and then slowly pour the next liquid down the spoon. This may take some practice but it will help you build a nice rainbow in your glass.

So that's how it works…

The same volume of two different liquids will have two different weights, because they have different densities. The liquids with lower densities (weigh less per volume) will float on top of liquids with higher densities (weigh more per volume). You can test this out by weighing the ¼ cup measurements of each of your liquids to see what each one weighs. The oil and water are close in density, oil is slightly lighter than water, but they don't mix together because the types of molecules they're made of are very different. Molecules that are similar will mix together more easily, like water and juice. The oil stays on top of the water because the oil is less dense, or lighter than water, so it floats on top of the water. See if you can add more layers to your density rainbow with different liquids, like baby oil, honey, or glycerin.