Wow
Right off the bat that's pretty impressive. Hey, what's up guys welcome back to lab today?
I am here with cody from Cody's lab. You know this guy you love this guy
I got him here today because we're playing with Mercury
Now the inspiration for today's video comes out the comments from Brown thunder who says do a video explaining
What the inches of mercury mean so I have cody here from cody's lab to help me explain?
Exactly why we measure in inches of Mercury so this vacuum Gauge here,
which is a very common type you'd see here in the us you see these outer numbers here. They're actually
referencing inches of Mercury. See Mercury used to be used as a way to,
uh, Measure differential pressure, cause a heavy liquid and it takes a lot to pull it up the Tube and it takes, ya know
If you measure the distance you're pulling of the tube you can know how much of a vacuum you have. This gauge
just does it without Mercury now back in December
I tried a project where actually built this vacuum chamber
Just using simple materials from the story in this case a glass cookie jar
And I have this liquid filled gauge on the top and as we suck the air out of the jar
We measure things in inches of mercury. I got three pounds of liquid Mercury right here, the purest stuff
I've had and what I find is really impressed about these these are very very tiny bottles be like an ounce of water
But when you pick these things up, they are impressively heavy it don't drop
I mean
This is about 1 pound of Mercury if you can imagine that so it's actually it's a little bit of a mind blow to feel
That it feels about same weight as brass or copper
Maybe a little bit heavier, so these bottles are actually full of dental mercury
This is what dentists used to use to make fillings. You know mix this with powdered silver push it into a cavity and it
Harden up and be chemically resistant and quick fix your tooth which is kind of mind-blowing if you think about putting mercury in your mouth
Now what would actually happen if we got mercury in our mouth would that be concerned as metallic mercury. It's actually fairly
Okay, spit it out. You'll be fine. Okay
It's only when it's dissolved into a solution that can be absorbed another body. It's really a problem. So this is a branded
Argenteum now that's actually the word for silver
And I'm pretty sure this is just referencing that this is quicksilver. Which is another name for Mercury
Yeah, I always thought quicksilver had to do with surfing so like the shirts I used to wear quicksilver
But actually quicksilver in a second term is mercury
I think it's called quicksilver because it's silvery in color and if you drop it
It moves quickly a couple it moves very quickly, and we don't want to drop that today
So mercury is an extremely heavy liquid
It's very dense 13 times heavier than water and so if you try to pull it up a tube, you'll reach a point
Where you cannot pull it up any more because you know you're not really sucking a liquid of the tube just the atmospheric pressure
pushing it up into the vacuum
You're creating at sea level you get about fourteen point seven pounds per square inch pushing down and so you should be able to lift
The equivalent of 14 pounds of Mercury so we have a long glass Tube here
it's very narrow and cody just challenged me to see if we could put one end into a bottle of mercury and
Suck the other end like a straw and see we could suck a hard enough to get the mercury in our mouth so that is
A risk I'm willing to take for you can we suck Mercury vertically through a Tube?
You know a distance of four and a half feet
So drop down to the comment to take a second to tell us who you think sucks more?
You really?
Alright guys a quick update these rods are a little bit too long, so kota
Just used his cool little glass cutting tool when we trimmed them down to about 36 inches or about three feet
so I have one job and my only job right now is to make sure the bottom of this measuring stick stays level with the
Top of the Mercury when cody starts sucking we're going to be able to measure in real inches of Mercury
How much vacuum he's able to pull all right cody you ready for this all right? Let's see what you got
Wow, right off the bat that's pretty impressive. He's already up to 20, so you got 19 inches of Mercury
And go any harder than that
Maybe if I tried really hard all right, let's try it again all right 19. Inches is good. It's not that impressive
You start freezing nitrogen around 22? Oh?
There's 22
But all we can do what do you see there 22 and 3/4 okay here? It comes LfO bounces on the way up
boom okay, so at 21 22
It's kind of bouncing there so stuart settles out for about 21 and 3/4 how's your mouth stealing cody ah?
It takes a lot of work
So I'm just like kind of pumping the air with my tongue trying to evacuate as much of the air out of Tube as I
Can especially as hard as I possibly can and I was unable to pull the mercury all the way up to
The vacuum pump that I'm using says it can pull 25 inches of Mercury
And I filled with a lot of the reactions
I do it's right around 22 inches of mercury that I see balloons expanding I see water boiling xSede liquid nitrogen
Freezing cody got up to 21
It's like almost 20 to 21 and 3/4 which actually wasn't too bad
So theoretically if you could suck hard enough for long enough you might be able to freeze liquid nitrogen like yourself
That's cool. All right. I'm going to jump in and see what I can do
We'll do that 4.4
the best licks more
Shall we get to the point where saliva boiling?
Ya
Mean want to pull out, but yet
Hey, oh yeah. See there's none of that oh
Whoo that was interesting though it felt like as I was moving the tube up the mercury is actually dropping back down the Tube
Like it was jiggling even though I was moving yeah as you move the rod up. You know a mercury actually went back down
Yeah, Mercury is always going to stay at the same height above the surface of the Merc which is interesting right?
it's not like you can just plug it and move this thing around it's like as I moved it up the Mercury went down as
I moved it down the Mercury went back up
This time I'm going to try and pull it out, and I'm going to set it back down beside the disks there, okay here
we go
oh
Yeah, career fect oh that's amazing. Let's take a second to just talk about what happened there
So what we saw?
Here is actually pulled a vacuum above the mercury the air pressure pushed some retreat up the Tube
And we weren't able to get a perfect vacuum, but we were able to actually get a pretty decent vacuum. We pulled the mercury of
23 something check out my tongue I
Was trying to hold the vacuum with my tongue. It's like sucking my tongue down inside. I think it's an interesting point
It's not necessarily that I was sucking the liquid up
It's just I was reducing the pressure and the outside air pressure
Was pushing the mercury back ups all right and since mercury is so heavy the distance that air pressure can push it up is
Just a couple of pieces yeah once you get up around there 24 25
It gets very very difficult to go any higher like what would you consider a perfect vacuum in inches of Mercury so at this altitude?
We're not at sea level right now
25 inches of Mercury would be about a certain vacuum if you're at sea level would be about 29
That's really interesting because when you think about it the closer you get to sea level the more
Atmosphere you have pressing down and so when you reduce the atmosphere inside the Tube
There's actually more pressure to push it up so at sea level
29 inches of Mercury might be close to perfect vacuum and our altitude here
It's closer to 25, so that's very interesting that by sucking it by mouth
We can actually approach very very closely to those numbers however that last inch of mercury is kind of where all the magic happens
Now we're going to hook the vacuum pump up and see how high the vacuum pump can pull the mercury
When I bought this vacuum pump here it claims to be able to do 25 inches of Mercury
Which we read on our gauge all the time
So we're put that to the test with real mercury and real inches and observe the difference exactly
Cody's over here trying to rig everything together with glass and torches and do everything professional
I think I'm just going to shove this down the tube use a little electrical tape and see if we can Jimmy rig it that
way
All right, what do you think that can do it? Yeah? We'll get a
Glass Tube connected to the poly vacuum Tube. We're going to draw with the machine power and see how machine compares all right here
We go man versus machine let's kick on the pump
Well, that's back
So it's like to turn men women can go ahead
Yeah, a little bit of momentum there probably turn it on now
top of the Mercury
25-ish be a high-pressure day
There's a little over 25 yeah 3 almost on a twenty six
Twenty five and three quarters and the bottom of the ruler is matching the top of the mercury it is
1325 and three quarters. Yeah, is it creeping its way up a little bit more
Not really. It's just kind of hold. I know you always knew you're right, but now I know why you're right
right on right on
So cool. Let's talk about this for a second kody sucked the mercury up almost 22 inches of Mercury
I got almost to 24, and I think this elevation a full vacuum would be somewhere around 25 little more than 25
We've got this way up to 26 - is that really accurate
Both the air pressure is high you know it's this nice day then the pressure will be higher and the Mercury will go a lot
More fact that's how barometers work and to go over to my channel. That was a little ordinary building next
So very cool experiment man versus machine
I think what we saw is the machine actually sucks about an inch or two of Mercury more than we do
But what's interesting is that inch or two makes all the difference in watching the actual reactions inside of a space?
Another thing is just making sense to me now is the reason that they probably use Mercury's in the old
Thermometers is because it's such a dense metal
So it takes a lot to move it and that way you can compact it into a small space. It's one reason
I mean if you used like a really light metal like aluminum your thermometer would have to be like ten times bigger
Yeah, like the old alcohol thermometers actually had a spiral because out and so mark no kidding. That's cool
So on the periodic table of elements Mercury is actually listed. HG correct great. That's why if you look at the gauge
You're actually going to see a little in Hg. It's actually measured in inches of Mercury now
you know
If you guys like these mercury experiments and the things that we're doing to glass tubes check out what we're doing on
Cody's Lab's channel. We're building barometers to actually measure the differential and pressure around us. Like on a good day
So the pressure is higher than on a rainy day, and a barometer can be used to predict that very old technology
But still very relevant today, and we use it all the time you just don't know about it because now it's on Google weather
so hopefully this helps answer the question of why gauges are measured in inches of Mercury that puts a little visual with it and of
Course a big thanks to our friend brown thunder for requesting this in the comments below you can go ahead and check your YouTube inbox
Brown thunder or sending 25 bucks. Thanks for joining us for this experiment today
We'll be looking for you the next one talk to you there
It comes a little bit numb from stretching so hard
Don't put Mercury in your mouth guys