The Hydrophobic Head and the Hydrophilic Tail

The reason why just rinsing your hands off doesn't work as well is that all the dirt and all that stuff that builds up on your body has oil in it. When you, when you wet your hands with water, you get it nice and primed. Then when you add soap and you lather the soap up, what you're doing is you're introducing those soap molecules to a single little particle of cake frosting. And they essentially surround it. It surrounds and basically traps the dirt in the oil in what are called my cells - M-I-C-E-L-L-E-S.