 So this is how we're going to make our dilution series. Remember, we're making a 1 in 10, a 1 in 50, and a 1 in 100 dilution solutions. So the first thing we're going to do is to add water to our test tube. So we're using three test tubes here to make our three different solutions. So the first one requires nine mils of water. So we're going to measure that, put it into our test tube. And for those who need to know how to use a pipette, see the previous video that was done on this. So the first test tube has nine mils of water. The second test tube is going to have 9.8 mils of water. So our serological pipette has increments that will allow you to measure 9.8 mils. So we add that to our next test tube. And then to the last test tube, we're going to add 9.9 mils of water. We add this to our test tube. So we have added the water to the test tubes. Now we need to add the varying volumes of our stock dye. This is our stock dye here. So we move the water since we're going to work with our dye. And we want to add one mil. So actually, we're using a different pipette pump that's specific to a one mil pipette, serological pipette. So we're going to add one mil of stock dye to the first test tube. And when we add this one mil, we're going to mix the dye in the water by pipetting up and down, as you see me doing here, doing it gently and not forcing the liquid out of the pipette tip so that you don't lose your solution. And this will also allow your solution to be accurate. So when I've pipetted about five or six times, then I have made my one in 10 solution. So I can put that to the back of my test tube rack. And then since I made a lower concentration of my blue dye, I can put the same pipette into my stock solution because it has a less concentration than my one in 10 dilution. Now if I was using the pipette or in this particular solution, I would not add it back to this one because it would change the concentration. It would actually make my one in 10 more concentrated. So you can move your pipette from less concentrated to more concentrated solutions, not from more concentrated to less concentrated solutions. So here I'm now going to make the one in 50 dilution. So I do this by adding 0.2. So I'm going to add 0.2 mils so you adjust your pipette so that you can see the 0.2. So I'm going to add this 0.2 mils of stock dye to my water in my second test tube. And I pipette up and down like before. So I have made my one in 50 solution. And then because I have some liquid already in this pipette, I'm just going to change it. And then I'm going to add 0.1 mil of stock dye to my 9.9 mils of water in my third test tube. And I pipette up and down carefully again. And then I've successfully made my one in 100 solution. So if you were to look at them side by side, this is my one in 10 solution, my one in 50, and my one in 100 solution. And if you notice, it gets less concentrated from one in 10 to one in 100. So that is how you would make a dilution series.