In this video, TalkingScience's own kitchen chemists demonstrate the emulsifying properties of dish soap.
What you need:
The food coloring allows us to see the separation of fat from liquid. Dish soap has both polar and non-polar properties, meaning it can separate the polar water from the non-polar fat in milk. Whole milk has the highest fat content out of the various milks, so it works best for this demonstration. The soap acts as an emulsifier, essentially chasing the fat in the milk away from the water in the milk, making magic milk!