Hello and welcome. Today we're going to take a look at calibrating the pH probe using SPARKvue.
Either on the computer or on the SPARK Science Learning System, the procedure is the same.
Whether you are using a pH Sensor, a pH/ORP/ISE Sensor, a Water Quality Sensor, or the Chemistry Sensor,
you're going to be using the same procedure to calibrate for pH.
I'm going to go ahead and use the Chemistry Sensor and I'm going to connect that to my SPARKlink.
Then I'm going to take my probe and connect that to the end of the sensor.
You'll see on my screen that I have a variety of measurements that are now showing up.
I'm going to take the pH probe and I'm going to remove the soaker bottle that comes with it, carefully,
and I'll set that aside.
I'm going to take the o-ring that holds the cap and I'm going to move it back so it's
out of the way so I can still take measurements even though the cap is still there.
The first thing I'm going to do is rinse off that probe to make sure that it is good and
clean and doesn't have any of that fluid still on it.
I can blot that dry if I want to keep it from diluting the solutions I use.
Now I'm ready to set up for calibration. So the first thing I want to do is create a SPARKlab,
because that is where that calibration is going to be saved.
So I can use either one of my paths. I could Open a file. I could go to Show. I'm going to use Build.
I'm going to select pH and create a couple of displays that are commonly used with pH.
Once I have those in place, I'll say OK. And now I have a SPARKlab created and that is,
again, where my calibration is going to be saved.
I'm going to go down to the tools in the lower right hand corner here, and that is where
I'll find the Calibrate option. So let's select that.
You'll see it shows that I have the Chemistry Sensor connected, and the measurement that
comes up by default is Temperature.
We want pH, so I'm going to touch on that to select for pH.
You'll see it's already set up for a two point calibration. That's what we want to use with
the pH sensor. So I will say Next.
You'll see it automatically comes up with the two points shown.
I'm using a pH 4 buffer and a pH 10 buffer. You'll see it set up with 4 and 7 by default,
but we can change that.
So I'm going to start off with my 4. I'm going to take the probe and stick it into the 4 buffer
and I'm going to hit Read from Sensor.
That's going to take a value from the sensor and it's going to associate that with pH 4.
Then I want to take that out and rinse it off thoroughly so I'm not mixing my buffers.
I'll set that aside and blot once more.
I'm going to put that in the pH 10.
So what I need to do on the screen here is change 7 to 10. Say OK.
I'm ready to read from that second point. I'm going to scroll down one and hit the
Read from Sensor button.
Now it's going to associate that value with a pH of 10.
Now that I've finished the calibration, I can rinse that off.
Once I say OK here, it's going to save that calibration in the file.
Say OK again and now I'm ready to measure. So let's go ahead and do that.
I'm going to start collecting data.
And I'm going to stick that in an unknown.
This is a fruit juice, so I'm anticipating it will be an acid.
Sure enough, looks like an acid to me.
I only have to do this once at the beginning of an experiment, typically.
So I can now go on and do several measurements and as long as I'm still using this file,
I should be OK.
We hope you enjoy using this sensor with your students and don't forget to practice safe science.
Thank you.