Visualization of Mercury vapors in UV light

Toxic mercury vapors are invisible under the daylight but you can clearly see them in the UV.
First part of video recorded under normal light and second part taken under illumination by Mercury resonance line (253.7 nm). Background is a luminescent screen.

[theCodyReeder]

How did you film it? I want to do this experiment.

[davidkennedydds]

This is a really well made video demonstrating the visualization of mercury vapor. Your camera really picked up the smoke well.

[endimion]

The tubes that glow behind the LCD matrix do contain mercury in its elemental form which is the safest form. Also, the amount is ridiculously small. It's vapour under very low pressure and the tube is tiny. And it doesn't come out. Don't worry, they're perfectly safe.

[olivergorrie]

this is the coolest thing ive seen today

[goingclear]

Yikes!!! I remember playing with mercury globs when I was young, when a thermometer happened to break. That was probably safer than having it stuck in my teeth for 35 years.

[endimion]

As with any liquid in a closed container at constant temperature, a dynamic balance is established when the amount evaporating equalizes with the amount coming back into the liquid.
If bottles of water don't explode (and water evaporates MUCH faster), nor any other containers in stable conditions, thermometers won't either.
It has nothing to do with the container thickness.
The only danger from bursting would be if the liquid had no space to expand, as liquids aren't easy to compress.

[mollya.]

Scary... to think how uncautiously we tend to handle liquid mercury...

[skeptical_thinkers]

This scared the shit out of me. I am never messing with mercury again.

[fifty]

@squidwardDK I believe there is a draft in the room or a fan that's moving the vapour. at the beginning it moves downward but then gets stirred up.

[catchable]

@Polopalapop We are seeing the UV shadow of the mercury vapor on a luminescent screen.

[RichFeldman]

Some commenters say "why doesn't the mercury vapor move downward"? The UV shadow shows vapor in air, at a concentration that's only a few parts per million even if saturated. The maximum density increase from Hg is much less than the density decrease from a 1 degree temperature rise.

[jaarex]

Opary rtęci są szkodliwe. Przeprowadziłem w świetle UV ten eksperyment patrząc gołym okiem nic nie widać, ale gdy filmujemy kamerą opary stają się widoczne, ten eksperyment trzeba przeprowadzać w pomieszczeniu wentylowanym, gdyż rtęć wchłania się również przez drogi oddechowe w postaci par. Z płuc dostaje się do krwi, gdzie wnika do erytrocytów, w których jest utleniana, wnikają też do mózgu i przenikają przez barierę łożyskową do krwi. Uszkadza nerki, trzustkę i płuca ma działanie rakotwórcze.

[harrytuttle]

When I was in school kids used to carry bottles of mercury into class for show and tell. Today this would get the kid arrested and the school evacuated. It is amazing how we all survived.

[mipesco]

@squidwardDK
My guess is the video is in a fumehood ( a cupboard that sucks in air). So the flow of air is drawing the Hg vapours up

[LNMagic]

@squidwardDK Some fluids mix freely, even if their densities are different. It's similar to the way many solids that are heavier than water (sugar and salt) can dissolve in water without undergoing a chemical reaction. Also, gases tend to mix. The vapor was clearly flowing towards the right, so that means that there is some airflow in that direction. Any flow with gases is likely to overcome the relative differences when the temperatures are the same - dissimilar temps don't mix as well.

[awitzke]

Mercury vapor is heavier than air so should be going straight down rather than rising or going sideways. nice visualization of water vapor though. you can even see it coming out of the second breaker before he pours it

[endimion]

Gases (this is a very, very dilute Hg vapour so it behaves like a true gas) mix. Gravity doesn't affect this. It's simple diffusion and convection.

[squidwardDK]

@iasedu 1 dl of Hg is a lot, but say 15 ml (one tablespoon) would release 4 microgram per second. Playing with mercury for 10 minutes, that is 2400 microgram. In an office-size room of 25 cubic metres, this is almost 100 micrograms per m3. This concentration of 0.1 mg/m3 is actually the US maximum level ('never exceed' level) for work health. In a medium-sized classroom (100 m3) you can play with this amount for 40 minutes before reaching the limit.

[davidkennedydds]

Can I use get a high quality copy of your excellent video to use in one or more of my public access movies about mercury poisoned dental personnel?

[squidwardDK]

@squidwardDK Thanks for replies. Yes, there is clearly an air flow and it must be under a fume hood, would be stupid otherwise. Also, gases are volatile to any air flow (I guess this is what @LNMagic explains?)

@WakeUpSleepIsDeath Yes, only very little of ingested metallic mercury is absorbed in by the body, while 80 percent of inhaled mercury vapour is absorbed. Mouth and gut bacteria and fungi can both methylate and demethylate mercury. Thus a cycle of excretion and reabsorption can go on.