Mercury 'surface tension' vs. density

[Danger]

This probably belongs in one of the physics or engineering forums, but I don't know which one... so I post here with a request that it be moved if appropriate.
Back in the early 70's, I desired to build a diorama of the Enterprise and a D7 Klingon cruiser. It would, of course, have to be fully lighted, but I wanted more.
My idea for a photon torpedo strike, at that time, was to drop a blob of mercury (about half of what you find in a tilt switch) down a glass tube, with spotlights on it. I didn't like it, but it was the best that I could come up with at the time.
Given my current state of unemployment and borderline boredom, I might actually be able to build the thing. Now, of course, I have to choose between a couple of dozen versions of Enterprise, but that's beside the point.
My current thought is to drop a bead of mercury down a strand of 'invisible thread', which illusionists use for close-up magic tricks. You can't see the stuff from more than a few inches away. There will be a red laser aimed down along the thread from the firing ship, and another aimed upward from the target. That should result in a nice shimmering red object traveling from one ship to the other, and then splattering when it hits. A recycling system will then collect the mercury and return it to the torpedo reservoirs.
What I need to know from any physicists, chemists, or engineers is whether or not mercury will actually follow a thread. My personal suspicion is that it will simply fall straight downward due to its weight, rather than follow the thread. Due to the toxic nature of the substance, I prefer to not experiment with it to find the answer on my own.
Any help?

 

[Blenton]

You could try praying for it to happen.

 

[Pythagorean]

You could try praying for it to happen.

Hey, he didn't intend this post for OT. I went through a lot of trouble refraining from making a joke about the planet mercury being too massive.

(Can you tell that we don't know, Danger?)

 

[Astronuc]

This probably belongs in one of the physics or engineering forums, but I don't know which one... so I post here with a request that it be moved if appropriate.
Back in the early 70's, I desired to build a diorama of the Enterprise and a D7 Klingon cruiser. It would, of course, have to be fully lighted, but I wanted more.
My idea for a photon torpedo strike, at that time, was to drop a blob of mercury (about half of what you find in a tilt switch) down a glass tube, with spotlights on it. I didn't like it, but it was the best that I could come up with at the time.
Given my current state of unemployment and borderline boredom, I might actually be able to build the thing. Now, of course, I have to choose between a couple of dozen versions of Enterprise, but that's beside the point.
My current thought is to drop a bead of mercury down a strand of 'invisible thread', which illusionists use for close-up magic tricks. You can't see the stuff from more than a few inches away. There will be a red laser aimed down along the thread from the firing ship, and another aimed upward from the target. That should result in a nice shimmering red object traveling from one ship to the other, and then splattering when it hits. A recycling system will then collect the mercury and return it to the torpedo reservoirs.
What I need to know from any physicists, chemists, or engineers is whether or not mercury will actually follow a thread. My personal suspicion is that it will simply fall straight downward due to its weight, rather than follow the thread. Due to the toxic nature of the substance, I prefer to not experiment with it to find the answer on my own.
Any help?

Given the toxicity of mercury, I'd say that it's probably not a good idea, even if the drop of mercury would adhere to a very thin wire and slide down. In addition to surface tension, it would require sufficient adhesion and resistance to shear. A small enough drop might work. The splatter would seem problematic - with dispersion of mercury.

Nevertheless - it's a cool idea.

 

[zoobyshoe]

You don't need the thread. You arrange the two ships relative to each other as you want them, then tilt the whole set and camera such that the mercury drop simply falls straight down.

 

[Danger]

I went through a lot of trouble refraining from making a joke about the planet mercury being too massive.

Never hold back.

Zooby, I should have specified that this isn't for a photograph or movie. It's to be a permanent display in a glass showcase. The glass is partly so I don't have to dust the thing, and also to contain any vapours or droplets from the mercury.
I'll probably never get around to building it, but I can have some fun with the design stage.
Astro, as always you are the voice of reason. I agree that it probably isn't worth messing with mercury. Unfortunately, I can't think of any other substance that will give an approximate visual equivalent without either drying out or polluting the thread. Maybe I can string some crystal beads directly onto the thread, but that severely complicates the reloading system. Hmmm...
Maybe I'll do some experimenting. Aluminum powder suspended in something like glycerine might be a decent starting point.

Thanks to all for the input.

 

[Mech_Engineer]

I too think using Mercury is a bad idea, but I like idea of a silver bead falling along the string... Or maybe just shoot a fluorescent airsoft pellet under a blacklight?

 

[zoobyshoe]

Zooby, I should have specified that this isn't for a photograph or movie. It's to be a permanent display in a glass showcase. The glass is partly so I don't have to dust the thing, and also to contain any vapours or droplets from the mercury.
I'll probably never get around to building it, but I can have some fun with the design stage.

Not your fault. My brain registered "diorama" as "panorama" and I assumed you meant a movie or video shot.

The same solution might apply: since it's enclosed in glass you could set it up on a tilt so the mercury, or any liquid, need only drop, but change the angle the viewer sees with mirrors, i.e. looking into the glass one is actually looking into a mirror. I have no idea what sequence of mirrors would change the angle in the proper way, but I suspect it's possible to get any final desired angle of view.

 

[Pythagorean]

Danger,

how about a vortex generator and a laser?
use a smoke generator or dry ice for the medium.

 

[Proton Soup]

oil will certainly follow a thread, or at least a wire. about 30 or more years ago, there were these popular tacky home decorations with beads of oil running down wires around a statue or something. maybe you could get something like a suspension of gold powder going.

 

[Danger]

To the last 3 respondents...
Zooby... I like that mirror idea, but it wouldn't be my first choice. Definitely something to keep in mind, though.
Python (I hope you don't mind me calling you that; it's sort of my pet name for you.) Dry ice is sort of eliminated as a possibility simply due to this being a closed system. If, by vortex generator, you reference a glycol-based smoke machine... cool idea, but it will conflict with the original idea of the display. (I am willing to compromise, though, so I'm not discounting your idea out of hand.)
Proton Soup... that must have been during one of my hibernation periods. I sort of went from lava lamps to plasma globes with no clue as to what went between. I've never heard of the oil/string stuff that you referred to. Still, it's something to keep in mind.

 

[Borek]

I doubt mercury will stick to the thread. It is not surface tension that counts, but http://en.wikipedia.org/wiki/Wettability - if it won't wet the surface, it won't stick. And my bet is it won't wet, it is not called quicksilver without a reason.

--

 

[zoobyshoe]

it is not called quicksilver without a reason.

What's the reason?

 

[Borek]

Mobility. Most liquids wet most of the surfaces to some extent, so they stick to them; that slows their motion. Mercury dosn't stick to surfaces, so it moves very fast and easily.

--
methods

 

[zoobyshoe]

Mobility. Most liquids wet most of the surfaces to some extent, so they stick to them; that slows their motion. Mercury dosn't stick to surfaces, so it moves very fast and easily.

1 : not dead : living, alive
2 : acting or capable of acting with speed: as a (1) : fast in understanding, thinking, or learning : mentally agile <a quick wit> <quick thinking> (2) : reacting to stimuli with speed and keen sensitivity (3) : aroused immediately and intensely <quick tempers> b (1) : fast in development or occurrence <a quick succession of events> (2) : done or taking place with rapidity <gave them a quick look> c : marked by speed, readiness, or promptness of physical movement <walked with quick steps> d : inclined to hastiness (as in action or response) <quick to criticize> e : capable of being easily and speedily prepared <a quick and tasty dinner>
3 a archaic : not stagnant : running, flowing b : moving, shifting <quick mud>
4 archaic : fiery, glowing
5 obsolete a : pungent b : caustic
6 archaic : pregnant
7 : having a sharp angle <a quick turn in the road>

http://www.merriam-webster.com/dictionary/quick

I think the "quick" in "quicksilver" refers either to definition 1 or 3: "living silver" or "flowing silver". I don't think it means "fast silver"

 

[Pythagorean]

Python (I hope you don't mind me calling you that; it's sort of my pet name for you.) Dry ice is sort of eliminated as a possibility simply due to this being a closed system. If, by vortex generator, you reference a glycol-based smoke machine... cool idea, but it will conflict with the original idea of the display. (I am willing to compromise, though, so I'm not discounting your idea out of hand.)

The vortex generator itself is pretty simple and can be built easily (I'm thinking of a vortex ring generator, specifically. I thought it was the Romulans or the Klingons that fired ring-shaped rounds).

Anyway, there are many simple ways to build the vortex generator itself, but you can't actually see the vortex without a medium like smoke or steam. Here's one made out of a soup can:
http://www.eskimo.com/~billb/amateur/vortgen.html

You can get one of those ultrasonic humidifiers and have cold steam for a medium, but then you'd have to have a place to put water into your device, and an outlet for moisture to escape. That may be a little more open than you'd hoped for.

 

[Danger]

Borek, thank you for that link. It pretty much cleared up my questions. While I don't consider Wikipedia to be the ultimate answer to everything, it is very useful.

 

[Borek]

http://www.merriam-webster.com/dictionary/quick

I think the "quick" in "quicksilver" refers either to definition 1 or 3: "living silver" or "flowing silver". I don't think it means "fast silver"

English is my second language, so I can be wrong, but my feeling is that it refers to the second meaning, especially:

2 : acting or capable of acting with speed: c : marked by speed, readiness, or promptness of physical movement

If you have ever played with the mercury that pretty well describes its behavior.

Could be I am skewed by the fact that in Polish it is sometimes called "żywe srebro" - "żywe" means

adj 1. (żyjący) living; live; alive: ani ~ej duszy not a living soul; ~e kwiaty the natural flowers; (fig) ~ obraz living image;~a waga live weight; inwentarz ~ livestock; jak ~ life-like. 2. (świeży) raw ~a rana raw wound; dotykać kogoś do ~ego touch sb IN the raw; zranić kogoś do ~ego to cut sb to the quick. 3.(ożywiony) animated. 4. (ruchliwy) lively; vivacious; active; quick; brisk. 5. (intensywny, jasny) bright: ~e kolory vivid colours. 6. (prawdziwy) deep; true; sincere; keen: ~e współczucie deep sympathy; ~e zainteresowanie keen interest. 7. (o języku, mówiony):~ język living/modern language.

(see 4th) and srebro is silver.

 

[zoobyshoe]

English is my second language, so I can be wrong, but my feeling is that it refers to the second meaning, especially:



If you have ever played with the mercury that pretty well describes its behavior.

Could be I am skewed by the fact that in Polish it is sometimes called "żywe srebro" - "żywe" means



(see 4th) and srebro is silver.

In English we have this old phrase "the quick and the dead", in which "quick" means "living":

Mercury, the element acquired the name "quicksilver" because of its liquid, fast flowing properties. It is highly reflective, and its way of moving at the slightest touch give it a quality of almost being alive. In a previous age, the word "quick", was used to refer to things that were alive, not just things that were "fast". (This is why we still hear references to "the quick and the dead".)

http://www.indepthinfo.com/mercury/quicksilver.shtml

"Fast" verses "slow" silver doesn't make much sense, but "living" and "flowing" verses "dead" and "static" (i.e.solid) silver does.

 

[lisab]

When I was a young, a neighbor kid had some mercury that we all played with. Yes, we handled it, tried not to drop it...poured it from hand to hand.

In my experience, it's called "quicksilver" because it's 1) silver colored, and 2) very "fast" in your hand...think of wiggly jello that has no adhesion to what it's sitting on. The way it moves, it's almost as if it's alive.

Sigh...I often wonder how I survived my childhood .

 

[Andre]

When I was a young, a neighbor kid had some mercury that we all played with. Yes, we handled it, tried not to drop it...poured it from hand to hand.

In my experience, it's called "quicksilver" because it's 1) silver colored, and 2) very "fast" in your hand...think of wiggly jello that has no adhesion to what it's sitting on. The way it moves, it's almost as if it's alive.

Sigh...I often wonder how I survived my childhood .

Hmm, was I that neighbor kid? I have the same story. The mercury came for an clinical thermometer that broke on a favorable place to collect the mercury.

It surely does not stick and it surely is very quick.

 

[Borek]

Sigh...I often wonder how I survived my childhood .

That's the wrong question. The right one is - why do kids now are supposed to not survive?

 

[Mk]

The fears of mercury poisoning expressed in the thread are strange to me. Surely the effects are negligible when working with only one droplet, as Danger has specified. The primary sources of alarm with mercury are from children eating dried paint (?) off of walls, and from the biomagification of it in organisms high up the food chain.

 

[zoobyshoe]

The primary sources of alarm with mercury are from children eating dried paint (?) off of walls...

Here, regarding paint, I think you're confusing mercury and lead.

 

[Danger]

I used to think that mercury was only hazardous if ingested or if the vapour was inhaled, but an article in SciAm a few years ago scared the hell out of me. It was an obituary of a research scientist who worked with the stuff. Apparently one single drop got onto her skin, was absorbed, and killed her. Like Lisa and Andre, I remember mucking about with it as a child. All that we were ever told is "don't eat it".
It occurs to me, based upon suggestions of Zooby and Python, that I should specify the scale. Each of the ships will be about 1/2 metre long, so the case will be somewhere between 1 1/2 and 2 metres long by 1/2 metre wide and 1 metre high.

 

[Andy Resnick]

Just to address the OP, Hg has a very high interfacial energy (430 dyne/cm, IIRC- about 10 x water), and as been pointed out; unless Hg wets the thread, it won't follow it.

However, Hg will wet copper, so a bare metal wire may work. The high interfacial energy means that the drops of Hg will not likely splatter upon impact, but could simply bounce.

 

[Borek]

However, Hg will wet copper, so a bare metal wire may work.

I think that won't work for long, because of amalgam formation.

--

 

[Bob S]

When I was a teenager in ~1950, I used to visit shut-down mercury mines in California and "pan" mercury from the dirt near the retort condensation tubes. I had ~10 pounds at one time, with significant spills on my bedroom rug (I survived). Mercury will easily amalgamate copper and silver, but mercury dissolves these metals very slowly. It will cause rapid oxidation of aluminum. Amalgamated copper will turn a grey (gray?) color after several weeks, and need a touchup with more mercury. Metallic mercury is relatively harmless when compared to the organic methyl mercury compound found in fish..
Bob S

 

[MotoH]

what if instead of using a proton torpedo (thinking starwars here since star trek isn't my specialty) You use a DBY-827 heavy dual turbolaser turrets, IE a laser. Get a laser with a very large emitter (not sure if right word?) so the beam is noticeable, and have it set up to a button on the front of the display case so when you press the button the beam will shoot across to the other ship and maybe have a small motor to turn the laser so it walks across the ship. Paint a track of burnt metal on the enemy vessel and add to the glory of the firepower.

Or you can just use a laser and use a short burst and slow down light enough to be able to see it!

 

[Danger]

I'm going to need a couple of beers to think on that last one.

 

[DaveC426913]

When I was a young, a neighbor kid had some mercury that we all played with. Yes, we handled it, tried not to drop it...poured it from hand to hand.

My wife was given Mercury to play with in science class. Now that she's in health care and knowledgeable about toxins, she too wonders how she survived childhood.

Metallic mercury is relatively harmless when compared to the organic methyl mercury compound found in fish..

I have always wondered about this. I have heard that there were two types of Mercury, one organic and one inorganic but I never understood it - it's an element!

 

[Danger]

I have heard that there were two types of Mercury, one organic and one inorganic but I never understood it - it's an element!

Hold onto that thought, pal. I have a panel of my comic that directly references this, but I'm having a hell of a time trying to remember how to use Illustrator 6 which it is stored in, so as to upgrade it for publication. Laugh if you like, but I've gone through 4, 6, 8, 10, and CS. It's like trying to learn to read all over again, and I don't have the manual any more. :grumpy:

 

[Bob S]

See section on methylization of mercury in
http://www.usgs.gov/themes/factsheet/146-00/
Bob S

 

[Danger]

Hey, Bob. I was absent for a couple of days and lost track of this thread. Thanks for the link; it's very informative.