Color Changing Milk Experiment

Color Changing Milk Experiment

Do your kids finish all the milk in their bowl of cereal? If not, you can put that milk to good use and teach your kids some science.  

What you need

  • milk
  • food coloring in different shades
  • liquid dish soap
  • Q-tip (optional)

What to do

  • Pour milk on a dinner plate. (I get my kids to transfer it out with a spoon. Good practice for pouring and coordination). 


  • Add food coloring – one drop of each. Option #1: right in the center of the plate and keep the drops close together. Option #2: one drop of each color on each side of the plate. 


  • Touch the tip of a Q-tip in the middle of the color blob in the middle of the milk. If don’t have a Q-tip, use a finger. Don’t stir the mix!!  

Did anything happen?  

Not yet!

  • Now soak a fresh Q-tip in liquid dish soap. (If you don’t have a Q-tip, dig a finger into the soup). Place the soapy end of a Q-tip (or your finger) in the middle of your plate of milk and hold it there 10-15 seconds. Don’t stir! 

What is happening?  

Is milk started moving around!? 

Soak another Q-tip in liquid dish soap and place it in a different place in the milk. Do you see a beautiful burst of color? And how exciting is it that milk continues to move even after Q-tip is removed.  

Color Changing Milk experiment is a fun way to use that milk in the bottom of your cereal bowl.


The Science Behind Color Explosion

The composition of milk varies depending on an individual animal, but on average milk is 87% water, 4% fat, 3.4% protein, 4.8% lactose, and 0.8% minerals (such as calcium).  
Dish soap alters the relationship between the parts that make up the milk. When the tip of your Q-tip (or finger) introduces the dish soap into the mix, that dish soap weakens the chemical bond that holds the proteins and fats in solution.  
Some soap molecules start racing around trying to join up with the fat molecules in the milk. In response, the molecules of fat bend, roll, twist, and contort in all directions.
During all this movement the food coloring molecules are bumped and shoved out of the way, allowing us to see all the invisible activity between dish soap and milk.  
Why does the movement stop?  Because milk and soap become evenly mixed. We haven’t tried this experiment with 1% or fat-free milk, but that’s what we are doing next.


What is your favorite color experiment?




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