in this video, we're gonna do a quick refresher on Oz Moses. So you guys know that as Moses is simply a type of diffusion, and diffusion is the movement of a substance from high concentration down toe, lower concentrations of the same substance and, as Moses again is a specific type of diffusion. And so, as Moses is the diffusion of a solvent across a semi permeable membrane, or remembering that allows some substances to cross but prevents other substances from crossing. And so the solvent is usually going to be water, especially in biological systems, and osmotic pressure is the pressure that's required to prevent the flow of the solvent. And so really, osmotic pressure is a measure of the strength of osmosis. So the higher the osmotic pressure, the greater the strength of osmosis. Now, in our next video, we're going to talk about the direction of osmosis. But before we get there, it's important to note that as Moses direction depends on the tennis ity of the solution and so recall that the tennis ity refers to the relative concentrations of salutes, not solvents, that air dissolved in the solutions. And so really there are three different terms that refer to the tennis ity of a solution. And those three terms are isotonic hype, a tonic and hyper tonic. So isotonic refers to a solution that has the same solute concentration as another solution. And again, salute here is incredibly important because tennis City refers to the solute concentration, not the solvent concentration. So the next term is going to be Hypo Tonic. And so Hypo Tonic kind of sounds like Low Hypo Low. So hype Atomics Solutions have lower solute concentrations than another solution and the opposite of hype. A tonic is going to be hyper tonic. And when I think of hyper, I think of a kid that's had way too much sugar and they're just running around all over the place. And so because they've had too much sugar hyper, this is a solution that has a higher, uh, saw you concentration than another solution. And so what's really important to note is that these three terms here are words of comparison, so you could Onley use them when you're comparing one solution to another solution. So in our example below, we're going to compare the outside solution of the cell to the inside solution of the cell, which is separated by a plasma membrane. And so we're going toe label the tennis ity of the outside solution. So in our first scenario of our example, the outside solution, which is in light blue, is separated by a semi permeable membrane, and the inside solution is in the yellowish like oranges. Brownish type color here, mustard color on. We have these green salutes that air dissolved and so notice that the outside solution has a lower solute concentration than the inside solution. Because there's less green dots in, ah, certain area. And so because Thea outside solution has a lower solid concentration, it's going to be hypo tonic in comparison to the inside solution. Now, over here in the next scenario, noticed that the concentration of salutes these green dots here is exactly the same on the outside and the inside solution. So that means that the outside solution is isotonic with respect to the inside solution and then, in our final scenario over here, notice that the outside solution has a much greater solute concentration than the inside. And so because the outside has a higher solute concentration, it's going to be hyper tonic. And so again, the tennis city here is going to control the direction of osmosis. And we'll talk about the direction of osmosis in our next video, so I'll see you guys in.