 Hello and welcome to this video about volumetric pipettes. Volumetric pipettes are used to pipette small amounts of aqueous solution and it's going to be used to make dilutions and it's also very commonly used in biochemistry. Volumetric pipettes come in different volumes and the one I'm going to show you now has on the top, you can see what the volume is. So this pipette has a range between 20 and 200 microliters. To set the volume that you're going to use you can look at the side and there is this wheel that you can turn and you can see the volume that is actually pipetting. In this case we're going to dilute 100 microliters of copper sulfate into a 10 volt so we need 100 microliters on this pipette and the other pipette that we're going to use is set to 900 microliters for a total of 1 ml. So you have to make sure that the number is aligned with this tiny arrow on the bottom so this is now set to 100 microliters. But before we can use the pipette we have to make sure that we're actually pipetting into a pipette tip because if we use it like this we're pipetting directly into the mechanism and it will slowly break the pipette. So pipette tips come in to do different colors. We have yellow and blue. The yellow pipette tips meant for this specific pipette are calibrated between 2 and 200 microliters and you can attach them to the bottom of your pipette or by putting the pipette into the box where they're in. And we have the blue ones which are calibrated from 200 to 1000 microliters and they fit on the larger pipettes. To use a pipette you push the top part of the pipette down and you feel that it will have some resistance. This is the part where it actually pipettes the amount that you set. You can also push harder which will require more force but then it will blow out everything that's left into your pipette tip. There's also a bottom in the back which you can use to eject the pipette tip and that's used to get rid of the pipette tip without you actually touching the pipette tip with your hands and possibly contaminating your hands. Always dispose of the pipette tips into either a small beaker or directly into the solid waste or at the end of the day dispose everything in your beaker into the solid waste. Also what you should never do is when there's any liquid involved to hold the pipette sideways or upside down because then the liquid will go into the mechanism and it will slowly destroy the pipette. So always keep your pipette upright and when you're done, hang it back into the stand. So now we're going to use the pipette to make a 10x dilution of our copper sulfate into... So we have a copper sulfate solution, we have pure demi-water and we have the file that we want to make our dilution in and we want to dilute it 10 times. So first we take our yellow pipette which is set to 100 microliters and we attach a yellow tip to it and then we carefully press the pipette to the first stop and we submerge the pipette into the copper sulfate solution and slowly release it to suck up the 100 microliters of copper sulfate. Now you have to be careful not to touch any sides of the glassware because it will slightly drain a bit of the solution from the tip and also do not dry off the tip with a piece of tissue paper because that's all in the calibration of this pipette. Then you put it into the receiving file and against the glass side of the file and then slowly press down to pipette out all the solution and then when most of it is... when everything is gone and you wait a few seconds you press down completely to make sure that any residual liquid is being added to your flask. After that you dispose of your pipette tip and you hang your pipette back on the rack. Now we need to add the remaining 900 microliters and for that we use a bigger pipette which is calibrated between 100 and 1000 microliters and this requires the blue pipette tip. This one is set to 900 microliters and then carefully press down to the first stop submerge it in water slowly release it to suck up all the water wait a few seconds remove it from the flask put it into the new file slowly press down to release all the water and then end with the vigorous press on the top to make sure that everything is out of there and dispose of the pipette tip and hang back the pipette back on the rack. Now you can close your vial and carefully mix everything to make a perfect dilution and this is how you use volumetric pipettes.