Soap molecules not only form spherical micelles in water, they also form spherical vesicles, which you can picture as thick-walled hollow spheres. Here is a cross section of such a vesicle, with the blue regions representing water:

Unlike a micelle, a vesicle traps water in its interior. What gives a vesicle this ability? (If you are having trouble with the difference between micelles and vesicles, think of a baseball and a hollow rubber ball. The baseball, with no empty space inside, is analogous to the micelle, and the hollow ball is analogous to the vesicle.)