Scroll through the slideshow above for a visual of each step.
- Pour milk into the baking dish to cover the entire bottom surface of the container.
- Add drops of food coloring to the milk.
- Pour a small amount of dish soap into a bowl or cup, and touch the tip of a cotton swab into the soap.
- Gently touch the surface of the milk with the soap-covered swab.
- Watch as the colors move and swirl, as if by magic – but it’s actually science!
Questions to Ask Your Kids:
- What did you notice?
- What happened when you put the cotton swab in the milk?
- Why do you think that happened?
- Why do you think it stopped moving around after a period of time?
The Science Behind Magic Milk
Milk is made up of molecules: minerals, proteins, and fats. When the cotton swab enters the milk, it breaks the surface tension, allowing the molecules to start moving. The dish soap on the cotton swab reacts with the fat in the milk. The soap molecules move around and try to attach to the fat molecules in the milk. Normally, you would not be able to see this happening, but the food coloring allows you to see all the movement taking place!
- Try pressing another dish-soap-covered cotton swab into the milk to see if there are any more fat molecules that haven’t been found. If you still see movement, there were still some fat molecules on the loose!
- Try this experiment with 2%, 1%, or nonfat milk. Do you notice a difference from what happened with the full fat milk?
- Try this experiment with water. Do you think the colors will still move around like they did in the milk? Why or why not?
Support the Museum
The Virginia Discovery Museum is a vital nonprofit community resource, but we will be closed through at least May 31 due to the COVID-19 pandemic. Please consider a donation to support us during this uncertain time. Donate Now