 So, this is how your spectrophotometer is going to look, the one that you probably will be using in the lab. So I'm going to show you some important features of this spectrophotometer, and there are certain knobs here that you need to be familiar with, for example. This is the home screen where it will bring you to this interface where you have a series of suggestions that you can select. So we're going to use the spec 200 modern interface option. So our enter button is actually this circular button in the center of the arrow buttons. So we press that, and if you notice it gives us this display, and we are going to be measuring in the live display mode. And we can either measure in absorbance or in percentage transmittance. So if you notice in your lab write-up, there is a calculation to calculate the percentage transmittance and the absorbance, but you won't have to use a calculator to do that in this case. You actually will get a reading of your absorbance. If you want to change the measurement from absorbance to transmittance, all you need to do is to press the right arrow, and if you notice the sign percent T comes up, so whatever you measure will be the percentage transmittance. And next you see here the measurement. So right now it's telling you that you're going to be measuring your absorbance at 675 nanometers, which is your wavelength. So your wavelength is depicted in nanometers. Now if you want to change the wavelength at which you're reading your absorbance, you can use this dial here. If you notice lambda is written on the dial. So you can, first you have to go to the measurement mode. Now you can do one of two things to change the wavelength. If you want to change it by one, by increments of one nanometer, you can go either left. So if you notice it's now 676, 677. If you want to bring it down, you could go to the left arrow, which gets you to 676, back to 675. If you want to change it in increments of 10, you can use this dial over here to the left, mark lambda. So it will go up to from 6, what was it, 675, it can go, if you turn the dial clockwise to 685, if you want it down anticlockwise, it will go to 665. You can also use this dial to do fine adjustment, if you press down on the knob and you turn it, it will go in increments of one nanometers, either up or down. So that's how you would adjust your wavelength. Now if you want to actually do your measurement, you have to press your down arrow until it gets the go letters. And if you notice whenever your words are highlighted in green, it means that that's the highlighted thing that will happen if you press enter. So if you press enter, it will go and then start measurement. So nothing is in our sample holder yet. So I'm just showing you where you're going to actually put your samples. Now if you notice here inside of the spectrophotometer, there's a light source which is right here. So this light source is actually sending light from the monochromometer and this is going to hit your sample, which can either be in the place where a cuvette is or it could be in the place where you put your test tube. So I have here a cuvette. I can put the cuvette in here if my sample, let's say this was my sample, I could put it in and you'll notice it fits very snugly into the cuvette holder. And then I could press enter, no, I can actually then determine the absorbance. So it's telling me right now that the absorbance is, sorry, it's actually telling me the percentage transmittance, it's in 83.3%.