我想問呢水銀有咩用處？

Thermometers (obviously)
People think that mercury is only used in thermometers. However, mercury is a great electrical conductor and is often used in electrical switches and relays.
Sphygmomanometers (blood pressure monitors)
Esophageal dilators (also called bougie tubes)
Cantor tubes and Miller Abbott tubes (used to clear intestinal obstructions)
Feeding tubes
Dental amalgam
Laboratory chemicals (fixatives, stains, reagents, preservatives)
The most common related compound made from mercury is methylmercury. It doesn't really have any uses, but it pollutes many lakes and rivers and poisons the fish.

2006-11-12 15:28:24 補充：
Industrial and chemical uses of mercury are manifold in the medical community: mercury is present in fluorescent and high-intensity lamps, thermostats and switches, and a variety of generators, manometers, and batteries.

2006-11-12 15:28:45 補充：
Non-medical uses of mercury are also present in a variety of products: cleaning solutions, preservatives, paints, and antifouling agents for wood and other surfaces.

2006-11-12 15:28:47 補充：
Non-medical uses of mercury are also present in a variety of products: cleaning solutions, preservatives, paints, and antifouling agents for wood and other surfaces.

2006-11-12 15:28:59 補充：
Some uses of mercury are purely playful or convenient, such as singing greeting cards, talking refrigerator magnets, lighted athletics shoes, and toys. Patients, visitors, and employees bring these products into the facility.

Many usage, but most of them can be substituted,
I try to answer what I know:

1.Barometer to measure the atmospheric pressure, in 1 atmospheric pressure is equal to 760mm mercury..... mercury barometer is seldomly used because it directly release mercury vapour

2.manufacture sodium hydroxide and chloride from brine by electrolysis, but this method is subtituted by other method

3.use in coulometric method of instrumental chemical analysis, because mercury can provide fresh metal surface and disslove other metal

4.amalgram: the alloy of zinc and mercury was used in dental remedy, but it not used now

5.Gold plating mercury - gold alloy can be paint on some object, after the evaporation of mercury metal gold left behind ( this method is not use now)

6.since the high density of mercury, it can be used in calibration of volumetric glass ware

7. reflecting material in glass thermo-flask, but now even glass thermo-flask is no more popular.

............ there are still plenty of mercury usage I had not mentioned, hope these can help you.....

Mercury usually used in clinical thermometer...

Mercury is used in clinical thermometer...
Mercury is used in the electrolysis of brine to make chlorine gas, and sodium hydroxide for industrial uses.....
Mercury is used in some of the cosmetics to make woman's face to look whiter....

thermometer