 I'm Kevin Slayer, I'm doing Dr. Research at the University of Quebec in Montreal. And I'm going to show you guys how to do soil pH. So we're going to be following the soil sampling and methods analysis of carbon and red rich. And basically we're going to be looking at organic samples. So we have here two grams measured out already. These have been dried by room temperature. And we didn't want to mix this with 20 milliliters of distilled water. So we just basically run that in, make sure you don't miss any bits. We'll set that down. Right here we're going to show different samples. So right now you could see that it's not mixing very well. So we're going to have to centrifuge it using this machine to mix the water. And then the material together will do this for about 20 to 30 minutes. Once that's completed and we have our solution ready for pH, we're going to be using the calibration machine. So we're going to be checking out pH meter. It's a VWR Symphony SBAPI. So I'm going to show you guys how to use this. So first we turn the machine on and first we have to calibrate it. So here's the pH probe for as you remove the cap. And if you can see there's a little probe in here. Now when you have prolonged use of this machine, the solution inside which is silver chloride, you have to replace that. So there's a little reading tube right here. If we slide this down, there's a little hole there. In order to make your measurement accurate, we have to make sure that this hole is open. So this is placed like such. And I'll just make sure that it's clean and ready to go. And then we can start calibrating. So the first buffer solution we're going to use is pH of 7.0 to calibrate the machine. So this is simply done by sticking the probe inside the solution. We press calibrate on the machine. Now this is ready for calibration. So when we slide the probe inside the solution, now the measurements reading 7.3 about still adjusting. Okay, 7.1. If we hold calibrate down, now we're given the opportunity to adjust it. So we'll adjust this to 7.00. That's this button right here to adjust the decimal position. So now that's set at 7, we press calibrate, we remove the probe from the solution. This machine needs to be calibrated twice once at 7.0 and the second solution at 4. So we clean the probe with distilled water. We work that down. And now we're ready for the second calibration. Make sure it's in there. So this buffer solution's been set at 4.01. And we can see that the machine's bringing it right down to 4.01 or close. If it's not correctly calibrated, we actually calibrated this a few moments before the video. So it should be pretty close to 4.01. Okay, I'll cheat time a little bit and set this. That's calibrated, and there we go. So now we're in the machine's calibrated. We'll just clean this off before we do a free soil sample. Make sure that's good and clean so it doesn't affect our results. Again, it's important to make sure that the hole is open on the top here to correctly measure it. So now again, we mix these with the centrifuge for about 30 minutes and then let it sit for an additional 15. So this is ready for pH. So we make sure that the probe is actually in the solution and we wait for the pH meter to be... So we're roughly getting a pH of about 4.5. And we'll stop it about there. 4.45, 4.46. So I'm comfortable with saying the pH of this soil sample is 4.46. So before we were to do another soil sample, we make sure that we clean off the probe again. And when we're done using the whole soil, you remove it. Make sure you cover the hole again so you don't have your solution, your sulfur chloride solution evaporating through the tube. And place the button on top, actually in the holder first, then place the button on top. Check your machine off. And that basically concludes how you do soil pH. Thanks a lot.