So my understanding of water flow is as follows:
Basically, water moves about randomly because it has thermal energy. It will occasionally hit other water molecules and "bounce" back. As such, in areas of high pressure, water bumps into other water molecules a lot. However, if a high pressure water tank were connected to a low pressure empty tank, some water would be hit in the direction of the empty tank, but it wouldn't get hit back. Over time, more and more water is hit over until the water pressure equalizes. A vacuum doesn't suck so much as not push back, if that makes sense. So my trouble with hypotonic/hypertonic solutions is as follows. In a hypotonic situation, the solute concentration outside the cell is lower than inside the cell. A hypertonic solution is the reverse. So a hypotonic solution has fewer water molecules, so you would expect water to flow out of the cell because it's not getting hit back as much. But it flows in. The reverse is true for hypertonic solutions. Why is this? Thanks!