In this video, we're going to talk about diffusion. Diffusion is the net movement of a substance from an area of high concentration down to an area of low concentration, and molecules have a natural tendency to diffuse with or down their concentration gradients from an area of high concentration to an area of low concentration. Let's take a look at this example image down below at the diffusion of dye and water. Notice that in this image, the blue circles represent water molecules, whereas the red circles represent dye molecules. Over here on the far far left, notice that this person is adding a drop of dye to this beaker of water.
Initially, when the person first adds the drop of dye, there's quite a high dye concentration in this one initial area, but in other areas of the beaker like here and over here and right here, you can see that there's quite a low dye concentration. There's really no dye at all. What starts to happen is diffusion is going to start to occur and the dye is going to start to diffuse to areas of low concentration, as we see here, from an area of high concentration down to an area of low concentration. That's what's starting to happen over here in this beaker. It's starting to diffuse and it's going to continue to diffuse from areas of high to areas of low concentration until equilibrium has been reached.
Equilibrium is just when the entire beaker has equal concentrations of the dye and the dye is evenly distributed throughout the beaker. This is the idea of diffusion. This concludes our introduction to diffusion and we'll be able to get some practice applying these concepts as we move forward throughout our course. So I'll see you all in our next video.