Density Rainbow



Let’s explore density by creating a rainbow in a glass! Density is the number of particles that make up an object. Weight is a measurement of the gravitational pull on an object. For example, think about swimming in a pool. You float right? What about a rock? A rock is denser than you are because it sinks but you probably weigh more!


  • Water
  • Food Coloring
  • 3 Clear Drinking Glasses (Mason Jars work too!)
  • Sugar
  • Measuring Cup
  • 1 tbsp for measuring the sugar
  • 1 spoon for mixing
  • Optional: Pipette or turkey baster

Project Steps

Step 1

In one of the glasses, combine:

  • 1/4 cup water
  • A few drops of food coloring (the color is your choice!)

Step 2

In your second glass, combine:

  • 1/4 cup water
  • 2 tbsp of sugar
  • A few drops of food coloring (a different color from the first glass)

Step 3

In your third glass, combine:

  • 1/4 cup water
  • 4 tbsp sugar
  • A few drops of food coloring (any color you haven’t already used!)

Step 4

Take your second and third glasses.

Slowly pour the contents of the second glass onto your third (or use your turkey baster!). When pouring, tilt the glasses so the liquid runs down the inside of the glass and doesn’t “splash” in.

If you pour too fast, the liquids will combine and not lay on top of each other.

Step 5

Now, slowly pour the first glass (water & food coloring mixture) on top of your layered colors!
You should have three distinct layers!

Step 6

How does this work? Try to use density in your explanation!

  • By adding sugar to the water, the water is becoming denser. Less dense objects can rest on top of more dense objects. Our glass with 4tbs of sugar and water was denser than the glass of 2tbs of sugar and the same amount of water. Water with only food color is the least dense.

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Here is a downloadable version of the activity. Please feel free to download and print this PDF!

Daily Prompts - Density Rainbow