March 2015

rainbow density towerRainbow Density Tower (3/4/15)


  • Honey
  • Light Karo syrup
  • Dawn dish soap
  • Water
  • Vegetable oil
  • Rubbing alcohol
  • Lamp oil
  • Food coloring
  • Tall, narrow glass or jar
  • Small cups for mixing colors


  1. Begin by pouring some honey into the bottom of the glass. Make sure the honey does not touch the sides of the container, or it could affect your tower.
  2. This part is completely optional, but highly recommended! You can mix some food coloring in with each liquid to make a rainbow tower! The only liquids you may have trouble coloring are the honey and vegetable oil.
  3. Next, slowly add each liquid one at a time, making sure they do not touch the sides of the container. The liquids should be poured in this order: honey, light Karo syrup, Dawn dish soap, water, vegetable oil, rubbing alcohol, and lamp oil. Don’t worry if the liquids mix a little bit when pouring them; they will eventually separate themselves because of their different densities!
  4. Do you notice what is happening? As you pour, the liquids are layering on top of one another! How crazy is that?!


The reason that these liquids are able to float on top of each other is actually pretty simple. The liquids that have a lower density will float on top of liquids that have a higher density. Density is how much “stuff” or molecules you can fit into a particular area. So the exact same amount of two different liquids (or anything!) can have different weights.


  • Try adding different liquids to your density tower!
  • What do you think would happen if you tried dropping small objects in your density tower? Can you find an object that will float on each layer?