Measure. Analyze. Learn.
This is the Vernier Flow Rate Sensor.
It's used to measure the flow rate of a stream.
And, the way it works is that you're going to put
this impeller into the water.
And, as the water flows past it, it turns this,
and there's a magnet in here,
and it basically counts the number of revolutions.
And, it comes pre-calibrated so that it knows however fast
it's going, it can determine what the stream velocity is.
Now, when you use this is a stream, you want to make sure
that you point this end upstream, and that you keep this part
off the bottom of the steam so that you don't run it into a rock.
You don't want to damage this.
Now, the device comes taken apart.
And so, to put it together, it's very easy to do.
And so, all I have to do is put the pieces together.
And, this gives me a handle, where I can put it down into the
stream without having to bend over and be able to do that.
So, all I have to do is put that together.
There we go.
And so, now we've got the device together there.
Now, the flow rate sensor comes with a five meter cord.
And, the reason for that is, it allows you to maybe collect data
without having to go into the stream.
At least your collection device.
You may have your collection device on shore if you wanted to.
Maybe one student goes out into the stream with the
flow rate meter, while the other student is on shore.
And so, that's why we have that.
The device can be wet up to this point.
So, this is the electronics.
This part needs to stay dry, out of the water.
Now there's a couple other pieces.
There are actually three other pieces that come with it.
And these are extensions on here, designed to allow you to
be able to place it down at different depths of the water.
And, I just put them in my pocket.
So, this allows you to control the depth
that you place the impeller in the water.
So, that's just basically a stand off
from the bottom of the streambed.
So, it just comes with that.
I'm going to use the LabQuest 2 for data collection today.
So, I need to plug the flow rate sensor into the device.
It's an analog sensor so it plugs into an analog port.
I've plugged the flow rate sensor into channel 1.
And, we have a little reading there.
I might want to zero the sensor, since it's not in the water.
And, like taring a balance your just basically,
you're just saying, I want it to read zero now.
Now, I'm going to do something else,
which is change the screen contrast.
I'll be outside, so it will be easier to see.
And to do this, I will go to the little house,
I go to "Preferences"; go to "Light & Power";
and then, down in the lower left hand corner,
there's a "High Contrast" mode.
And, when I close that out,
it will change the screen into a black and white.
Makes it easier to see outdoors.
Now, if we take a look at this part of the screen;
we see our default collection parameters.
It's "Time Based", so it look at flow rate as a function of time.
1 sample per second, for 3 minutes, or 180 seconds.
Well, that's fine for some experiments,
but I want to use a mode we call selected events.
And, what selected events will let me do,
is go to specific points in the stream,
and have it measure the velocity at that point in the stream.
So, I'm really interested in a specific site, on the stream there.
So, to change this, I just go to where it says "Mode:"
And I'm going to go up the top;
and, I'll use the pull down there;
and, I'm going to go down to "Selected Events".
And, it comes up here, and it says event "Name:".
So, you don't have to change that.
Sometimes you might change it to 'site', in this case, because
I might be interested in different sites along the stream.
So, to change that, I just tap where it says "event";
the keyboard pops up;
I'll type in the word "site".
And, say "Done".
And so, I've got it here where it's naming "site".
And, it won't have any units, because it's just a location there.
And, I'm actually going to do this.
I'm going to check the box next to where it says,
"Average over 10 seconds."
And, what will happen there, is that when I have it collect;
it's going to collect for 10 seconds, but display an average
value for the collection there.
So, I'm fine with that, so I'll hit "OK".
And so, now I'm ready to collect some data.
Now, what I'd like to do is show you how this would work.
It’s going to be difficult to actually film
in the river doing the data collection.
And so, what we'll do is, I'm going to hit the collect button.
And then, I'll start spinning the impeller.
And, I'm just going to start spinning it there.
And, I'm going to hit "Keep".
And, just keep spinning the impeller for the entire time.
And so, what it's doing right now, it's making measurements,
and it's going to do that for 10 seconds, and then when
10 seconds is done, it will actually display the value there.
And so then, we end up with that point of data.
And so, that's how I'll be doing
the data collection out in the stream.
Now, let's go collect some data.
So, now that I've set up the device for data collection,
I'm ready to begin.
So, I need to press the collect button.
And, when we do that, we end up with
the "Keep" button right next to it.
And, what will happen is;
that when I press that "Keep" button,
it's going to measure for 10 seconds,
because I set up that average over 10 seconds.
And it will display an average velocity at this site,
which is what I called it.
And, display that as a single point of data.
And so, at this point I'm ready to actually do the collection.
So, I'll stick it into the water.
Hit "Keep".
And, I'll just wait until it's finished.
And, there we go.
So, now I can move to a different location.
So, I've moved to a slower part of the stream.
So, I might want to make a measurement here.
So, I put it down into the stream.
Hit the "Keep" button.
And then, hold it there until the 10 seconds has elapsed.
So, I've moved to another site, even closer to the shore.
And, I suspect maybe that the stream velocity is slower there.
Let's make a measurement.
So, I put it in the water.
Press "Keep".
And, It's going to collect the data for the 10 seconds.
Now I've moved to a part of the stream where the waters
really seem to be flowing pretty strongly here.
So, I will hit the "Keep" button.
And, I'll just wait until it's finished.
And now, we've finished collecting data,
and we'd like to take a look at it.
So, I'm, look at the graph here.
And, we’ve got the four points where I collected the data.
And, probably for this, you'd just be interested in the
values at the various points here.
So, If I wanted to know the value at the very first point:
If I tap on that point, it actually tells me what the velocity is
for the stream at that point.
So, 0.639 meters per second at that point.
If I go to this point, then it tells me what it is there in the meter.
So, It's a different value.
And, I could just, in turn, tap on the different points,
and be able to look at those values in the meter.
So, we've seen the use of the flow rate sensor.
Measuring stream velocities.
So, you know, you could use this with students who are maybe
monitoring stream flows different seasons of the year.
So, it's part of an environmental science study.
So, if you wanted to do something like that,
then this would be the sensor you would need to use.