Color Changing Milk Science Experiment

Science experiments help us grow. Through experimenting and exploring we are able to ask questions, make assumptions, and then seek solutions. We are able to learn more about the world around us.

This Color Changing Milk Science Experiment is a fun activity to do with kids of all ages.

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Color Changing Milk Science Experiment

Color Changing Milk Science Experiment

What you need for this experiment:

  • Shallow pan or bowl
  • Milk
  • Liquid food coloring
  • Q-tips
  • Liquid dish soap

Color Changing Milk-2

Pour milk  a pie pan or glass bowl until it covers the bottom. Add drops of liquid food coloring to create a colorful pattern.

Dip a Q-tip in dish soap and place it in the center of the dish. Watch as the food coloring moves away!


Our Question:   What do we think will happen when we add dish soap (a surfactant – i.e. it cuts grease and fats) to the milk?   How can we watch the surface tension “break”?

Scientific background:   Surface tension is an interesting concept, like molecules like to stick together.  Milk has surface tension, just like water, but unlike water, it is high in fat and is solid colored. As the dye is less dense, it does not mix into the milk unless stirred. It remains separate.   Dish soap breaks down the fat of the milk and decreases the surface tension in milk.

Tips:  If you have gel dyes add a few drops of water onto them to help them be absorbed more quickly.

What kinds of questions can we ask?

  • What did the milk look like when you added  the dye? Why do you think that is?
  • What happens when you add the soap?   Why did the “dyed milk” disappear?   Where do you think it went?
  • Why did the colors return after the experiment has been running for a while?

color changing milk experiment

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