[PASCO Wireless Sensors]
[Acid-Base Titration]
Tom: Hi. I'm Tom Loschiavo, Education Manager here at PASCO scientific.
Ronn: I'm Ronn Fieldhouse, Training Specialist here at PASCO.
T: We're here today to talk about the Wireless pH Sensor and the AirLink,
and we're going to use them to do an acid-base titration.
Ronn is going to tell us about the setup.
R: This is our standard Drop Counter.
It comes with a syringe.
In this case, I've placed sodium hydroxide inside of it.
It has a double stopcock.
The top stopcock I'm going to use to turn off and on,
and the bottom is set for flow rate.
I've pre-adjusted that before the lab.
Our Drop Counter itself is a plate.
It has a hole in it with a photosensor,
And I can easily place my pH right inside one of the holes.
T: Now to do the experiment,
we're going to have to connect these sensors wirelessly to our computer.
R: First, I'm going to turn on the pH--
--that's simply hold down the button for a few moments,
and I can see the red light start to flash.
Our AirLink allows any of our standard sensors to become wireless.
I'm going to plug that in,
and I'm going to turn that on.
I can see once again the red light is flashing.
T: Now they're both on.
I'm going to connect them to the software.
In this case, I'm using SPARKvue software.
I'm going to touch the Bluetooth icon.
No need to go into the system settings.
It pairs right in the application.
Then I see my wireless devices.
If you're in a classroom setting,
there might be multiple pH Sensors and AirLinks around,
so you want to make sure your ID number
matches the ID number of your device in the software.
Since they match, I'm going to click on pH.
Now that's connected.
I'm going to click on my AirLink,
and that's connected.
Once they're both connected, I'm going to hit Done.
Now that they're connected to the software,
the measurements of both those sensors will appear on the Home screen.
Here's my Drop Counter measurements: Drop Sample, Drop Count, and Fluid Volume.
And my pH measurements.
Specifically, I'm looking at the pH in this case.
To do a titration experiment,
we actually have a structured SPARKlab available for you.
If you want to do that you can go into SPARKlabs,
and there's a SPARKlab called Titration Curves.
We're not actually going to use this titration curve experiment in the SPARKlab.
We're just going to build our own.
I'll show you how easy it is to get started.
Now I'm back at the Home screen.
I'm going to hit pH.
That automatically makes a graph of pH versus Time.
I don't want time.
I'm going to change that to Fluid Volume.
Now I have an appropriate graph for a titration curve.
Before I start though, if I wanted to calibrate,
if I wanted very accurate measurements,
very quantitative and accurate measurements of the pH and/or Drop Counter,
I could calibrate them.
There are videos in our video library that will show you how to do that.
For this particular experiment, the factory calibrations are appropriate,
so I'm just going to start data collection.
I'm going to start data collection here, and then Ronn...
R: Since this isn't running against time, it's running against volume,
I can take my time.
It's not going to start to record until drops start going through the Drop Counter.
I'm going to turn the top one on.
Sodium hydroxide is now dripping through the Drop Counter.
I can see the green light flashing meaning that it is lighting up,
and it's going down into the hydrochloric acid.
There's also phenolphthalein in there,
so after a little bit, you're going to start seeing it turning pink.
R: There we go.
It's going up through the equivalence point,
and it's plateauing out.
I can see that we've reached the top of the plateau,
or the top of the titration curve, and it's starting to plateau.
I can also tell its gone past the equivalence point
by the bright pink of the phenolphthalein.
I'm going to go ahead and turn it off,
turn it off by that top stopcock again.
And we'll let Tom analyze that data a little bit.
T: Minutes after starting this titration,
we have a nice titration curve.
I'm going to stop data collection.
I'm going to autofit this graph,
and there we see this beautiful titration curve.
From here now we can analyze the equivalence point.
Depending on the acid-base titration we're doing,
we could explore strengths of acids, concentration of acids,
even polyprotic acids and bases.
This is a great tool and set up for acid-base titrations.
If you want to learn more about this
and any other wireless sensors, go to pasco.com/wireless.
Thank you.
R: Thank you very much.