Milk is mostly water, but also contains fat, proteins, minerals, and milk sugar. Find out what happens when we add a surfactant to milk in this experiment bursting with bright colors!

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‍Materials:

- Bowl or Plate

- Milk

- Food Coloring

- Dish Soap

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‍Procedure:

1. Pour milk into the bowl or plate. You want just enough to cover the bottom.

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‍2. Add a few drops of food coloring to the milk. Use different colors for a more exciting effect. Do not mix it together!

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‍3. Using a spoon, stir stick, or your finger, add a single drop of dish soap to the middle of the milk in the bowl or plate. What happens?

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What's Happening?

Milk is mostly water, but also contains fat, proteins, minerals, and milk sugar (or lactose).

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When soap is added, it interacts with all three parts of the milk in different ways. The hydrophilic end attracts to the water in the milk and the hydrophobic end repels the water and attracts the fat molecules.

As the soap interacts with the milk, it carries the fat molecules through the water. It’s pretty hard to see – that’s why we added colors to it! The color allows us to watch the soap molecules search and attach to fat molecules. Once all of the fat molecules have been found by the soap, the food coloring will stop swirling!

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