And so they're much more polar than water. So because water does not actually have a full charge, it can pass across the cell membrane with ease. On top of that, we have many, many water molecules on the outside and inside of that bilayer membrane. And all these water molecules are continually colliding with the cell membrane. And because we have such a high number of water molecules, some of them are likely to actually pass across when they collide. So we see that water is the great exception to the rule above.