What you will need:
- Saucer or plate
- Food coloring (liquid) – several different colors
- Liquid dish soap
- Milk (whole)
- Cotton swabs (optional)
- Adult supervision
- Pour a small amount of milk into your saucer so that it is about 1/4” deep
- Add several drops of food coloring to your milk using various colors. Be careful not to disturb or stir the milk.
- Add a very small amount of dish soap to the center of your milk either in small drops or by dipping your cotton swabs into the dish soap and placing the (soap soaked) cotton tip into your milk.
What is going on?
As soon as you add the dish soap you will see an amazing display of color changing milk. I know that your parents have always told you NOT to play with your food but that is because they probably have never tried this experiment! So how does this work? Milk contains fats and proteins along with all of the water, vitamins and minerals. The tiny droplets of fat are actually suspended in the milk. The dish soap weakens the chemical bond that hold the proteins and fat in the milk. The dish soap molecule is bipolar. Its’ polar (hydrophilic) end dissolves in the water and its nonpolar (hydrophobic) end attaches to the fat in the milk. When you place drops of dish soap in the milk, the molecules of fat twist and roll around as they join up with the soap molecules. The food coloring gets pushed all over the place during the process and is a cool way to help us to see the action that is going on between the fat and soap molecules.
Try using different milks such as whole milk, 1% milk, 2% milk and heavy whipping cream. What difference do you see if any in the various milks that you have used? What about almond milk? Or, Lactaid? Does the brand of dish soap you use make a difference? Have fun but make sure to clean up your mess when you are done….