What for we use mercury?

Answer 1

Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some thermometers, especially ones which are used to measure high temperatures (In the United States, non-prescription sale of mercury fever thermometers is banned by a number of different states and localities). Other uses:

Mercury sphygmomanometers.
Mercury barometers, diffusion pumps, coulometers, and many other laboratory instruments. As an opaque liquid with a high density and a nearly linear thermal expansion, it is ideal for this role.
The triple point of mercury, -38.8344 °C, is a fixed point used as a temperature standard for the International Temperature Scale (ITS-90).
In some gaseous electron tubes, mercury arc rectifier
Gaseous mercury is used in mercury-vapour lamps and some "neon sign" type advertising signs and fluorescent lamps.
Liquid mercury was sometimes used as a coolant for nuclear reactors; however, sodium is proposed for reactors cooled with liquid metal, because the high density of mercury requires much more energy to circulate as coolant.
Mercury was once used in the amalgamation process of refining gold and silver ores. This polluting practice is still used by the garimpeiros (gold miners) of the Amazon basin in Brasil.
Mercury is still used in some cultures for folk medicine and ceremonial purposes which may involve ingestion, injection, or the sprinkling of elemental mercury around the home. It must be emphasized that the former two procedures, especially, are extremely hazardous and the latter is nearly as so because mercury spreads easily and is therefore ingested.
Alexander Calder built a mercury fountain for the Spanish Pavilion at the 1937 World's Fair in Paris. The fountain is now on display at the Fundació Miró in Barcelona.
Used in electrochemistry as part of a secondary reference electrode called the calomel electrode as an alternative to the Standard Hydrogen Electrode. This is used to work out the electrode potential of half cells.
Used in Cold Cathode (also generalised under the Neon Sign Industry) lighting to increase the success of ionization and conductivity in Argon filled lamps, an Argon filled lamp without Mercury will have dull spots and will fail to light correctly. Lighting containing Mercury can only be bombarded/oven pumped once. When added to Neon filled tubes the light produced will be inconsistent red/blue spots until the initial burning-in process is completed; eventually it will light a consistent dull off-blue colour.
Mercury was once used as a gun barrel bore cleaner.
Miscellaneous uses: mercury switches (including home Mercury Light Switches installed prior to 1970), tilt switches used in old fire detectors, tilt switches in many modern home thermostats, electrodes in some types of electrolysis, batteries (mercury cells, including for sodium hydroxide and chlorine production, handheld games, and alkaline batteries), catalysts, insecticides, dental amalgams/preparations and liquid mirror telescopes.

Thiomersal, (called Thimerosal in the United States), an organic compound used as a preservative in vaccines, though this use is in decline.
Historical uses: preserving wood, developing daguerreotypes, silvering mirrors, anti-fouling paints (discontinued in 1990), herbicides (discontinued in 1995), handheld maze games, cleaning, and road levelling devices in cars. Mercury compounds have been used in antiseptics, laxatives, antidepressants, and in antisyphilitics. It was also allegedly used by allied spies to sabotage German planes. A mercury paste was applied to bare aluminium, causing the metal to rapidly corrode. This would cause mysterious structural failures.

In Islamic Spain it was used for filling decorative pools.

In some applications, mercury can be replaced with less toxic but considerably more expensive galinstan alloy.

A new type of atomic clock, using mercury instead of caesium, has been demonstrated. Accuracy is expected to be within one second in 100 million years.

Answer 2

It is used in thermometers for measuring temperature, in dental amalgams, in making Siva Lingas for worship and in many chemical reactions. It is an important medicine in homeopathy.

Answer 3

theremometers
in the industrial of Glass :- u never asked urself how they get the glass very smooth like this
they poor the melting glass in a bath which is filled with murcury.
good luck

Answer 4

Its used in thermometers,barometers,cooking thermometers etc...