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Active Time
30-45 minutes
Total Project Time
30-45 minutes
Key Concepts
Liquids, density


Did you know that not only can solid objects sink or float, but liquids can, too? It is actually possible to stack different liquids on top of each other in layers. The key is that all the different layers must have different densities. You can stack them by either picking several liquids with a range of densities, or by varying the density of one liquid by adding chemicals like sugar or salt to it. If you choose colored liquids, or add food coloring to each layer, you can even create a whole rainbow of colors in one single glass! Want to see for yourself? In this science activity, you will stack several liquids, one by one, and create a colorful density column.


Svenja Lohner, PhD, Science Buddies

Styrofoam® is a registered trademark of The Dow Chemical Company.

This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Glass or cup
  • Tap water
  • Food coloring
  • Scissors
  • Ruler
  • Rubber band (wide)
  • Small piece of wax
  • Craft stick
  • Small, clear jars or transparent mini cups (2-oz) with lids (at least 2)
  • Permanent marker
  • Masking tape
  • Small piece of Styrofoam®
  • Tablespoons (3)
  • Dark corn syrup
  • Vegetable oil
  • Penny
  • Paper towels
  • Optional: Rubbing alcohol, dish-washing soap, and other liquids
  • Optional: Sugar or salt
  • Optional: Digital scale

materials needed for stacking liquid density science activity


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Active Time
30-45 minutes
Total Project Time
30-45 minutes
Key Concepts
Liquids, density
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