KENTUCKY — The definition of density is the amount of mass per unit of volume.  In simpler terms, density refers to how much of something is in a given space.  In the case of this Project Weather School experiment, the amount of water in each cup is constant and the only thing that varies is the amount of sugar per cup.  Therefore, the cup with the most sugar makes the water most Dense or “heavier” keeping it at the bottom of the glass.  Meanwhile, the cup with less sugar makes the water less dense (lighter) and it floats on top. That’s why the colors stack on top of each other to make a rainbow in a jar or glass or in whatever containers you want to  use.

So how does this work for weather?  Simply put, colder air is more dense than warm air.  Meaning, warmer air easily can be forced up , such as when a cold front moves into an area. Rising air can lead to cloud development and eventually rain.

Rainbow in a Glass

What You Will Need:
  • 4 Clear Plastic Cups
  • 1 Glass
  • 1 cup of warm water
  • Turkey Baster
  • Food Coloring (4 colors)
  • Something to stir with
  • 1 Spoon
  • 1 Sharpie
  • Sugar

How To Do It:

  1. Label each cup with a number. 1, 2, 3, 4
  2. In the cup labeled #1, put in 1 tablespoon of sugar… In #2, put in 2 tablespoons of sugar… #3, 3 tablespoons of Sugar…#4, 4 tablespoons of Sugar
  3. Use your turkey baster and put it in the cup of warm water and get a half an ounce . Do the same for each of the four cups.
  4. Stir the water until the sugar in each cup dissolves
  5. Match a food coloring with each cup, then put one drop of that color the cup and stir. Be sure to wipe your spoon after each time you stir a new color.
  6. Grab your glass, then pour contents of cup #4,the one with the most sugar,  into the glass or jar.
  7. Next, pour the contents of cup #3 into the glass, but do it SLOWLY.  If the colors start mixing, you’re pouring too fast.
  8. Next, pour the contents of cup #2 into the glass, slowly. 
  9. Finally, pour the contents of cup #1 into the glass, slowly.

Admire your rainbow in a glass, or jar. The most “dense” water is at the bottom & the "least dense” at the top.