A number of labs are going to use a drop counter.
Before I start talking about that,
always, always, always we have on our nitrile gloves
and our safety glasses and wearing the appropriate attire
for lab-- close-toed shoes and no big, bulky, flowing clothing
items.
So the drop counter is really useful
because it's going to basically measure the volume for us,
which is really convenient.
And there's a little IR sensor in the path, sort
of rectangular path cut away in the middle of this black brek.
I have to stop cocks on my plastic syringe.
I'm going to adjust the flow rate.
So how many drips per second with the top, and then
the bottom is just going to be on or off.
So off meaning that horizontal bar both are off.
I'm going to open the bottom, meaning vertical bar.
And then I'm going to start slowly opening the top one.
Every time there's a drip, you'll see a green light flash.
And this is a good rate, about two or three drips per second.
If you have a green light constantly on,
that means there's a splash or something blocking
and it's not going to work.
All right, so this is a pretty good rate,
but I'm not going to touch that top stopcock.
I'm going to close just the bottom,
and there's a stubborn drip on there.
Get out of there.
All right.
And I know I didn't just leave some paper towel residue
or splash because I don't have a green light on.
All right.
So now when I've set the drip rate,
now I need to measure the volume and then
I'll have to calibrate.
I'll have to tell the computer what that volume was.
So I'm going to go up to my set up, drop counter.
I want to make sure that these boxes have
X's, that it's going to zero automatically when I start.
It's going to have a drop count.
It will count the number of drops.
And I'm going to tell it the fluid volume.
So I'm going to click calibrate.
I'm going to open.
I'm going to make sure that it's going
into my graduated cylinder, which
is how I'm going to measure the amount of liquid.
Oh.
But some of my drips are going outside.
So that means I have to stop.
Because if some of my drips are going outside,
that means that I'm not collecting all of the volume.
So I'm going to start all over.
I always calibrate my drop counter
with just the d-I water from that plastic faucet.
I'm going to try that again.
My drip rate is still good.
So I'm going to click calibrate.
And then I'm going to turn it on using my bottom stopcock only,
make sure that those drips are being caught
in the graduated cylinder.
And in the book, it has to go to 10.
You can do five.
You just want to make sure that you're
going to measure accurately.
I think I'll go to four.
All right.
So then I'm going to tell it 4 mils.
Click OK.
And then it's going to be able to divide the number of drops
by the total volume.
So it's actually calculated what the volume
is for each drop, which is really convenient.
So it's not something you have to record.
The instrument does it for you.
So that's how to use a drop counter.