Chemistry is found everywhere, including in your kitchen!
Milk has multiple chemical properties that are perfect for a quick chemical reaction. Milk is mostly water but it also contains vitamins, minerals, proteins and tiny droplets of fats. Fats and proteins are sensitive to changes to their surrounding. Adding a little soap is enough to mix up their surroundings! It changes the weak chemical bonds and the food coloring molecules are bumping and moving around in the liquid!
At the same time, soap molecules combine to form a micelle, or cluster of soap molecules. These micelles are attracting the fats in the milk. This rapidly mixing fat and soap causes swirling and churning, making your milk “dance”! When the micelles and fat droplets have dispersed throughout the milk, the motion stops.