petition

To be honest though, mercury is nothing like as deadly as it is cracked up to be - the body has a pretty efficient disposal system for it.

Steve

On or around Wed, 25 Mar 2009 19:39:41 +0000, Steve Taylor enlightened us thusly:

quite. Mercury vapour is not too nice, but you can avoid exposure to that via common-sense.

And mercury doesn't have a very low vapour pressure either. I wonder just how long it takes to "evaporate" a say 1mm ball.

Steve

I wonder how long it takes to condense the small amount of mercury from a fluorescent tube when it's smashed ;-)

AJH

Not long I suspect. I've seen free mercury in a skip full of broken fluorescent tubes.

Steve

The 6.44g/cm^3 rather than 13.53g/cm^3 might have something to do with it. Your nice compact 30" (ish) barometer becomes a 63" (ish) one... You could use water in a barometer but then it's about 32 feet high. B-)

Has it? I thought it was culmulative poison but you needed fairly hefty exposure to suffer poisoning. Like being a hatter or japanese fishermen eating fish that do acumulate it. Willing to be educated on this.

Funny you should mention that, we just moved into "new" offices and the plant manager overruled my request not to bin all the tubes that had been taken out during the refurb and they were all smashed into the bottom of the general skip, on the grounds that as a commercial operation we pay a flat rate of GBP80/tonne for all that goes into the skip.

On a mildly related note a hybrid poplar was genetically engineered because of its ability to ingest mercury from contaminated land (where it could form more dangerous organic mercury compounds, see minemata's (sp?) disease) and vent it via the leaves as mercury vapour.

AJH

re:density, granted, but I have not seen many full size barometers like that though for a long time. Plenty of thermometers though.

Metallic mercury has a half life of about 3 days in the body, mercury compounds about 90 days.It isn't thought mercury is a cumulative poison now, just a very slow one, because a small amount daily can accumulate over time to a toxic level. Removal from the source will cause it to clear from the body.

Went over all this last week when I had to do some experiments with it at work. Needed to wet copper surfaces to try and measure the viscosity of the stuff under shear.

Surprised me too.

Steve

If that's the case, then why is it being banned?

ISTR there being sommat about it accumulating in just about anything connected with drains and sewers, e.g. rivers, sea life and so on?

So they ban a few expensive Barometers that will last generations and make us all buy CFL's full of mercury vapour that need special care with their disposal. Have you seen the instructions if one gets broken indoors? It does not make sense (as usual!)

You don't need mercury in barometers, it makes sense to ban it where there's better alternatives, although it would be better just to let it die out really, I can't see much demand for mercury barometers but maybe they've done the figures and have found out that there is, it's hard to know for sure really. Either way it's hardly the end of the world and of no real consequence, other than as a rallying call for the europhobes.

On or around Wed, 25 Mar 2009 22:47:36 +0000, Steve Taylor enlightened us thusly:

I've got one, and I want Russell Scientific to repair it... so I have a personal interest, too :-)

On or around Wed, 25 Mar 2009 23:57:10 +0000, Ian Rawlings enlightened us thusly:

so how come they're not being made with other stuff?

is there actually anything that's as good as mercury for a barometer? It's probably about the densest liquid out there.

and it doesn't make much sense to ban it, because it's not doing anyone any harm all the time it's in the barometer. And with sensible precautions the people working on them presumably don't die of it either.

At least two shops near me still sell stick barometers. Very tempting purchases. The cheapest was IIRC =A31,300 and the most expensive over =A330K!!!

Richard

Aren't they? I'm not exactly a keen barometer shopper ;-) Mine is a coil-type.

I don't think there's anything about it that's particularly unique in such a simple instrument so some substitute's bound to be available, after all anyone still wanting a mercury barometer is wanting one for show.

Same argument can be leveled at just about anything though.

On or around Thu, 26 Mar 2009 23:52:53 +0000, Ian Rawlings enlightened us thusly:

There's almost certainly nothing readily available that has the same properties as mercury, there by making it suitable as a replacement fluid for an existing barometer. To do that it'd have to have exactly the same density.

You can make a fluid-type barometer with any working fluid, but it needs certain properties to be practical, like high vapourisation point so that it doesn't evaporate, high density so the instrument is a reasonable size, and so on.

I grant you I want one for show. However, an aneroid barometer, to be any use (i.e. to read accurate local pressure or corrected sea-level pressure), has to be reset for altitude, using a mercury one as a reference...

no it can't. There's a thing about some anti-fungal agent in cheap Chinese-built sofas this morning, which has hurt or killed quite a number of the end-users. That's more valid as a ban.

Why would it need to have exactly the same density as mercury? Just needs it to be good enough, Mercury isn't the only fluid that can be used, and may not even be the best, but it was readily available a long time ago and so was used, but how do we know there's not a better alternative today? The NPL (national physics laboratory) certainly recommend the use of a good electronic one rather than mercury as they're more accurate these days.

A brief google around shows there's a few alternatives to mercury that are claimed to be just as accurate, one based on silicon fluid, don't know what the others are based on.

If you want one for show, alternatives are available, and if you want one for serious work, the NPL reckon the modern electronic ones are much better. It's not something to wring your hands over.

Yes it can, if you can keep the nasty stuff away from the people then what's the need for a ban, that's what you're saying, and that's true of anything. Dangerous animals, radioactive substances, poisons, anything. I don't see how your fungal agent doesn't fit this pattern.

Mercury is in the 20 most dangerous known elements, having large quantities of it in a largely ornamental instrument isn't a terribly good idea, whether it justifies a ban or not I don't know or care but it's hard to defend it.

Or pretty close, the galintium (or what ever it is called) mentioned recently has about half the density of mercury thus a barometer made from that needs to be about 6' high. Not sure of it's vapour pressure either, it might be too low...

Mercury is very dense, 13.5 tonnes/cu metre. Only 14 elements are denser and I don't think any of them a liquid at room temperature. Lead is only

I'd like one as well, the KISS principle. Might also be fun to have a water one but at 32' ish reading might be a problem but of course the top only needs to be 32' above the bottom and the tube doesn't *have* to be vertical.

Aye, I'm sure there are far worse things out there that deserve banning than the use of mercury in barometers, when there is no suitable alternative. Having said that mercury should be banned (and is if not by default) in consumable objects like batteries than generally end up in landfill.