So this process is known as symptoms diffusion. Now, we weren't actually wrong to think that because the membrane is, in fact permeable to water, and because of the small size of these water molecules, because of the fact that water molecules don't actually have a full charge, and because we have so many of these water molecules colliding with the membrane, these water molecules will, in fact, cross that membrane via the process of simple diffusion. Now, in 1992, things actually changed because in 1992 we basically discovered accidentally a special type of channel phantom membranes known as aquaporeans. And we realized that these aquaporeans are channels that selectively funnel allow the movement of these water molecules across the membrane. And the rates at which the water molecules moves through these aquaporeans are much higher than the rates at which the water molecules actually diffuse through that phospholipid bilayer membrane. And we'll see why that's important in just a moment.