Talk:Mercury-in-glass thermometer

From Wikipedia, the free encyclopedia

WikiProject Physics This article is within the scope of WikiProject Physics, which collaborates on articles related to physics.
Start This article has been rated as Start-Class on the assessment scale.
??? This article has not yet received an importance rating within physics.

Help with this template This article has been rated but has no comments. If appropriate, please review the article and leave comments here to identify the strengths and weaknesses of the article and what work it will need.

With reference to: "When Celsius decided to use his own temperature scale, he chose to set the boiling point of pure water at 100 °C (212 °F) and the freezing point at 0 °C (32 °F). One year later Frenchman Jean Pierre Cristin proposed an inverted version of the scale with the freezing point at 0 °C (32 °F) and the boiling point at 100 °C (212 °F). He named it Centigrade [1]."

  • This doesn't make sense. Both describe boiling at 100, freezing at 0. But the text says that Cristin's version is inverted. Which is correct?

Contents

[edit] Campaign against mercury thermometers

There is a campaign against mercury thermometers, which claims mercury is "unsafe" even when used in oral thermometers for medical purposes. What is Wikipedia's take on this? Do we endorse their view, or remain neutral? --Uncle Ed 17:20, 8 December 2006 (UTC)

WikiPedia has a Neutral Point of View policy (NPOV). In my opinion, if the mercury stays in the thermometer, it can't do much harm, but the potential for breakage exists, and mercury boils at room temperature, fumes get inhaled, etc. The porosity of glass is another issue, and I have not examined that. Intersofia 02:42, 9 December 2006 (UTC)

NPOV rules! Wikipedia has articles about land mines and rape and lots of religions. We say what they are, not if they are good or bad. It may be appropriate to have a factual section on the NIH or other campaigns to reduce the use of mercury thermometers. Chemical Engineer (talk) 17:31, 30 December 2007 (UTC)

[edit] Poison or hazard

Cut from article:

mercury is highly and permanently toxic to the nervous system and
Due to the possibility of mercury poisoning

What does this have to do with mercury thermometers? Has anyone been poisoned by such a small amount? Or is it more that doctors are law-abiding and will comply with a ban?

In other words, is the ban-mercury campaign starting with the least hazard but easiest group to get compliance from? Or are mercury thermometers really the biggest source of poison hazard?

What about science class, where they used to let you hold a big drop of mercury in your palm? How much hazard is there from 5 minutes of class play? Mostly from the fumes, right? Well how much hazard? I read all three ref's on my talk page and they were not specific. Yes, the ban is definitely in effect; but, no, it doesn't say how much danger there is from a broken mercury thermometer. --Uncle Ed 01:55, 9 December 2006 (UTC)

Need a source that indicates countries have banned. And yeah we all played with it in science class. I lost the one link that indicated that the hazard would be greater based on room size and lack of air exchange. CambridgeBayWeather (Talk) 16:57, 9 December 2006 (UTC)

re:mercury, vaccines, and autism--i've tagged for cite. please source or delete--it sounds like nonsense to me. Adavies42 22:41, 16 December 2006 (UTC)

I've removed the sentence as it has nothing to do with thermometers. Plus the AAP says there is no link]. CambridgeBayWeather (Talk) 23:39, 16 December 2006 (UTC)

The acute health risk from a mercury thermometer comes from swallowing or injection. Breaking an oral thermometer will relase mercury into the stomach leading to diahorrea but not usually long-term illness. The classic laboratory thermometer accident occurred when someone was forcing on through a cork or rubber bung: the glass broke and they rammed broken glass and mercury into their hand or forearm. Even from the glass, this could be a very nasty injury, and health monitoring was required until body mercury levels subsided.

The chronic risk comes from mercury vapour from broken thermometers or manometers since (despite what anyone tells you about zinc or sulfur) you will never pick up or render harmful all the drops which spread around. Many older laboratories and some schools had unacceptable levels of mercury vapour. I have seen documents relating to a laboratory technician who had to retire early due to ill-health from mercury vapour in his lab - his writing became shakier over the years. Pregnant women and their unborn children may be at greater risk.

I say don't panic, but let us not use mercury thermometers or manometers since there are better instruments available for measuring temperature and pressure. Chemical Engineer (talk) 17:45, 30 December 2007 (UTC)

[edit] Isaac Vs Jessica

I have just chatted to my daughter about replacing Isaac Newton's Name with her own. I am reasonably sure it won't happen again. I'll leave things as they are so that I don't stuff things up anymore —Preceding unsigned comment added by 203.173.29.23 (talk • contribs)

Thanks William M. Connolley 08:25, 5 June 2007 (UTC)

[edit] More on the technology of memory (or medical) mercury thermometers

The main article on mercury thermometers mentions that the space above the column of mercury in the capillary tube may be filled either with nitrogen or with "vacuum" (mercury vapor at equilibrium with liquid mercury).

In the discussion of the memory thermometer, or the medical thermometer (actually two separate Wikipedia articles, I think) there is a mention and a photograph of the mercury column separating just at or below a restriction in the capillary tube when the temperature falls, thus retaining the position of the mercury in the tube above the restriction.

I don't have reference to any authority, but I believe that for this principle to work, the space above the mercury column in these memory thermometers must necessarily be of the "vacuum" variety. In that way, the mercury is on the verge of turning from liquid to vapor everywhere, and even just a little resistance to flow (in the "restriction") is sufficient to cause this vaporization to happen exactly where the designer wants it to happen.

These instruments really are remarkable feats. How did the manufacturers get such consistency of dimenstions for the three (or four) different zones of the assembled glass tube? How did they introduce exactly the right amount of mercury? How did they seal the tube without overheating the mercury and making the whole thing explode? And they did all this with no computers and no lasers!

Jay.sinnett (talk) 00:31, 11 March 2008 (UTC)