Milk Surface Tension

Make amazing patterns using milk and surface tension.

Time: about 2 minutes.


  • A plate
  • milk
  • food coloring – any color(s)
  • dish-soap
  • paper clip (bend a portion straight for dipping into the soap)


  • pour a thin layer of milk onto a flat plate
  • carefully add a drop of food coloring in the middle of the milk
  • dip a bent paper clip into dish soap
  • now, touch the milk with the paper clip

Observation and Results:

  • What did you observe?
  • What do you think is happening?


Liquids such as water and milk have a property called surface tension. Surface tension is like a tighter skin on the edge of the liquid than inside the liquid. Another way of imagining this is that the water (or milk) molecules really like each other. In fact, they want to be surrounded on all sides by other water molecules. This makes them happy. The water molecules on the edge are not surrounded by other water molecules so they are trying to get back into the middle and surrounded. This ‘desire’ to be surrounded is what causes the surface tension. Soap has a property that gets in between water molecules thus counter-acting the surface tension.

Surface Tension Experiment Pictures

milk surface tension


Related Experiments

  • water drops on a penny (before and after soap)
  • scatter pepper on a plate of water


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Coco Science

Coco is interested in STEAM with a particular interest in the A. She has a hamster named Marshmallow and likes to read, craft, cook and dance.

One thought on “Milk Surface Tension

  • January 3, 2016 at 6:49 pm

    If I write a comment, it will go here…

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