Exploring Surface Tension with Milk, Food Coloring, and Soap

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multi colored swirls

Grade Level: First Grade

Book: Physical Science Unit: Matter Module: States of Matter


In this experiment, students will be introduced to surface tension and density through a colorful presentation.

Research Question:

What properties does surface tension itself affect? Surface Tension allows liquids to resist an external force. This property allows some objects that are denser than water to actually float. Surface tension results from the greater attraction of water molecules to each other than to air.


  • Food coloring in colors of your choice
  • Milk
  • Dishwashing liquid
  • A large dish with raised sides

Experimental Procedure:

  • In a pretty deep dish, add about ½ – 1 inch of milk.
  • Put a few drops of food coloring on the surface of the milk. The colors, amount, and arrangement can be however you like.
  • Put 2 drops of dishwashing liquid in the dish. 
  • Observe what happens to the surface of the milk.

Related Lesson:

States of Matter – Sillybulls
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