Swirling Milk Color Art

Shared by STEM Girl Day Partner: BASF Corporation

Recommended Grades: K, 1st, 2nd, 3rd

The Experiment: Discover how the molecules in milk and soap work with each other in this easy, colorful, swirling experiment. 

Share a video of your swirling milk experiment creation on Flipgrid.

Supplies:

  • Milk
  • Plate
  • Dish soap
  • Food coloring

Procedure:

  1. Pour milk on a plate.
  2. Add some drops of food coloring. You can mix and match colors.
  3. Add some dish soap.
  4. Be amazed at the swirls of color.

Learn more about what happened and why on the American Chemical Society website. 

Why did the colors move in cool ways? (from American Chemical Society)

To answer this question, we have to use chemistry. Think about the atoms and molecules that the milk and detergent are made of and why they would act in this crazy way when they are mixed…

The milk is made mostly of water molecules, but it also has fat molecules and protein molecules which are bigger than water molecules.

The detergent is made up of detergent molecules.

The cool thing about the different molecules is that they have positive and negative charges in different areas. Some molecules or parts of molecules have no charges.

When you first put the detergent on the milk, the negative end of the detergent molecules line up with the positive end of the water molecules. This causes the detergent molecules to zoom out in every direction over the surface of the milk and push the food coloring out toward the edge of the plate.

And when you dip the detergent down into the milk or bring it to the food coloring at the edge of the plate, there is usually some more swirling and movement of color.

The negative charge on the detergent molecules are attracted to the positive parts of the protein molecules. And the uncharged part of the detergent molecules lines up with the uncharged fat molecules.

There is a lot of moving as the detergent and other molecules twist and turn and switch around and different parts of the molecules come together. The food coloring molecules interact and ride along with all the other molecules, and that’s what makes the colors move!

Activity Video

Discover how the molecules in milk and soap work with each other in this easy experiment. All you need is milk, a Q-tip, food dye and dish soap! Tag us on your page so we see your milk art designs. #STEAMatBASF