Do thermometers really contain mercury? Did they really contain mercury in the past? It’s such a toxic substance, I can’t imagine it in a common household appliance.
Yes, many thermometers contain mercury and spilled Hg is a fairly dangerous substance. The Hg is being replaced with alcohol solutions but, ultimately, digital thermometers will rule. Hg is good because it has very good thermal expansion properties over a very wide temparature range.
The mercury in it’s metallic form is not nearly as dangerous as you might think. A single exposure (say, eating the mercury in a standard home medical thermometer) is unlikely to do serious damage, and will most likely pass through the system.
According to “Casarett & Doull’s Toxicology”, 5th Edition, pp:710, “Metallic mercury, such as may be swalled from a broken thermometer, is only slowly absorbed by the gastrointestinal tract (0.01 percent) at a rate related to the vaporization of the elemental mercury and is generally thought to be of no toxilogical consequence.”
The dangerous forms of mercury:
Mercury vapor - supposedly, one of the most dangerous things about accidentally eating elemental mercury is that it will get into your lungs, and vaporize. Mercury vapor “may produce an acute, corrosive bronchitis and interstitial pneumonitis”, and, if not fatal, may cause serious nervous system problems. Chronic exposure to mercury involuntary trembling, spasms, changes in personality, depression, delerium, hallucinations, and death.
Mercuric salts - look for severe cramps, bloody diarrhea, necrosis of the gastrointestinal tract, shock, circulatory collapse.
Mercurous mercury - be ready for hyperkeratosis, swelling of the fingers, pink-colored skin rashes, and irritation.
Methyl mercury - 1) numbness and tingling around the mouth, lips, extremeties, fingers, toes 2) ataxia, clumsy stumbling gait, difficulty in swallowing and articulating words, 3) neurathenia, general weakness, fatigue, inability to concentrate, 4) vision and hearing loss, 5) spasticity and tremor, 6) death.
The Prince: “Did you kill Jahamaraj Jah?”
Lady: “Yes.”
The Prince: “My Gods! Why?”
Lady: “His existence offended me.”
Ha! - you think the mercury in thermometers is bad, how about a large pool of it in the middle of the floor?
Alexander Calder created a mercury fountain in 1937 as a protest against the Spanish Civil War.
Try again. This link should take you directly to the fountain page.
You think that’s a big puddle of mercury? Check out the NASA Orbital Debries Observatory homepage. They use a 10-foot bowl of mercury on a turntable as a telescope mirror. The surface of a spinning liquid makes a perfect parabola, which is exactly the surface one needs for a telescope. Too bad it can only look straight up.
As a kid I had a bottle of mercury and played with it in my hands many times and I am still around… of course, it could be that had i not done that, I would be a supergenius 
I believe Spain was (and still may be for all I know) the first producer of Hg and the danger is for the workers in the mines and factories who were breathing the vapors all day but handling it like I did is safe.
When I was in gradeschool one of my teachers handed out mercury to us to play with. She told us we shouldnt touch it… but come on. I dont think anyone had any ill effects from it, but you would be talking a lawsuit these days. People who made hats use to rub it into the felt with there bare hands so the felt would stand up. Took them a long time to go crazy. Mad as a hatter.
I was sad because I had no shoes, until I saw a snake with no legs.
- A Wally original.
Since we’re throwing in links about big puddles of mercury…