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Mercury (element)

physical science Maturity 11-13 Next article →

Mercury is a very special chemical element. It has the symbol Hg and the atomic number 80.

Mercury symbol (fixed width)
Mercury symbol (fixed width)

Most metals are solid at room temperature. However, mercury is the only metal that stays liquid under normal conditions.

Mercury-27128
Mercury-27128

It is a heavy, silvery-white substance. It is so dense that a metal pound coin can actually float on top of it.

Pound-coin-floating-in-mercury
Pound-coin-floating-in-mercury

This happens because of a strong force called surface tension.

This metal works in many interesting ways. In a fluorescent lamp, electricity passes through mercury vapor. This creates ultraviolet light, which then makes the phosphor in the tube glow.

Mercury discharge tube
Mercury discharge tube

Mercury can also dissolve other metals like gold or silver. When it mixes with them, it forms something called an amalgam.

Amalgam
Amalgam

This can be used for dental fillings in some places. However, mercury is dangerous to touch or breathe. It is toxic to the nervous system and kidneys. Because of this, many tools use much less mercury than they used to.

EPA workers clean up residential mercury spill (3986684199)
EPA workers clean up residential mercury spill (3986684199)

People have known about mercury for a very long time. It was found in Egyptian tombs from 1500 BC.

Mercury-27128
Mercury-27128

In ancient China, some people thought it could help them live forever. They even made a mixture of mercury and jade for an emperor to drink. This was a mistake because mercury is poisonous. In the past, alchemists believed mercury was the "First Matter." They thought they could turn it into gold.

Mercury is quite rare in the Earth's crust. It is the 66th most common element there.

HgProductionPrice
HgProductionPrice

Most of the time, we find it in a red mineral called cinnabar. This mineral is known as mercuric sulfide.

Mercury-27128
Mercury-27128

Large mines were once found in Almadén, Spain, and Idrija, which is in Slovenia. In the 1500s, the Spanish used mercury to help get silver out of rocks. This was done using a method called the patio process. One big mine in Huancavelica, Peru, produced over 100,000 tons of mercury over 300 years.

You might see mercury used in science tools today. It is found in thermometers to measure heat.

Maximum thermometer close up 2
Maximum thermometer close up 2

It is also used in barometers to measure air pressure.

Barometer mercury column hg
Barometer mercury column hg

Some older machines use mercury switches to turn electricity on or off.

Mercury Switch without housing
Mercury Switch without housing

Even though it is useful, we must use it very carefully. Scientists and manufacturers work hard to keep it away from people and animals. This helps protect our health and the world around us.

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🖼️ Images & Media (12)
File:Pound-coin-floating-in-mercury.jpg
Pound-coin-floating-in-mercury.jpg
File:Mercury discharge tube.jpg
Mercury discharge tube.jpg
File:Mercury symbol (fixed width).svg
Mercury symbol (fixed width).svg
File:Mercury-27128.jpg
Mercury-27128.jpg
File:HgProductionPrice.png
HgProductionPrice.png
File:Maximum thermometer close up 2.JPG
Maximum thermometer close up 2.JPG
File:Amalgam.jpg
Amalgam.jpg
File:Mercury Switch without housing.jpg
Mercury Switch without housing.jpg
File:Barometer mercury column hg.jpg
Barometer mercury column hg.jpg
File:Mercury in Ice Core Upper Fremont Glacier.svg
Mercury in Ice Core Upper Fremont Glacier.svg
Joss paper burning on the street, Tai Po,...
File:EPA workers clean up residential mercury spill (3986684199).jpg
EPA workers clean up residential mercury...
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