Rainbows in Milk

Creating rainbows in milk is a fun science activity that uses ingredients from the kitchen.

Rainbows in Milk

You’ll need the following materials:

  • shallow pie pan (or other shallow dish)
  • milk, enough to cover the bottom of your pan (whole milk tends to work better, but use what you have)
  • food coloring, a few drops (any and all colors)
  • soap, a few drops (I used dish washing liquid and hand soap – both worked fine)

Let your children help with as many steps as they are capable.  This one is fun to just watch if they are too young to add the materials.

  1. Add enough milk to cover the bottom of your pie pan.

    Whole milk on the left; 2% on the right.
  2. Add a drop (or two) of each color of food coloring.
    See how the food coloring behaves differently in the 2% milk? {more water, less fat}

    Here’s how I set it up the 2nd time around. {using whole milk}
  3. Add a drop of soap on or right next to your food coloring.
  4. Watch the kaleidoscope occur!
    End result using whole milk with food coloring spaced out.

    End result after using 2% milk.

Rainbows in Milk Videos

To appreciate the coolness of this, you really must see it in action.  {I do apologize for the videography. It was difficult to hold the camera and add the soap!}




Depending on where you put the food coloring and soap and what kind of milk you use, you will end up with different results.  Let your kids experiment and have fun.

*Fun tip:  the more food coloring you add in the beginning the longer it takes to disperse when you add the soap!

The Science Behind It 

The soap reacts with the protein and fat in the milk.  The movement of the protein and fat causes the food coloring to move around.

Let me know how it works out for you!

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