Where does mercury come from?

Mercury

Mercury is usually found in rust-colored rocks called cinnabar.  The ore is crushed, then heated to release the mercury.

Mercury is perhaps the strangest of all metals.  It is the only metal that liquid at ordinary temperatures.

In nature, mercury is most often found in rust-colored rocks called cinnabar, although pure mercury can be mined.

To get the mercury from its ore, the cinnabar is crushed then heated to release and vaporize the mercury.  The mercury vapor then is caught and cooled.

Cooled, the vapors condense into a silvery liquid such as you see going up and down in a thermometer.

Because of its fluid quality and color, mercury is sometimes called “quicksilver.”  Anyone who has ever tried to pick up some spilled quicksilver will agree that the name is a good one.

When spilled, it  “breaks” into tiny balls that are hard to gather up.

Today, mercury’s unusual properties make it useful not only in thermometers, but in making thousands of products – from barometers and lights switches to pesticides. – Dick Rogers

How Does An Altimeter Work?

Altimeter

An aneroid (barometric) altimeter shows a plane’s altitude above the earth by measuring the atmospheric pressure, which lessens as the altitude increases.

An altimeter is an instrument that shows a pilot just how high his airplane is above the earth.  Most altimeters are aneroid (without air) barometers, made to read in feet of altitude instead of inches of mercury.

Like all barometers, the aneroid altimeter shows changes in air pressure, which lessens as the altitude increases.

Behind the dial is a small metal can called a diaphragm from which most of the air has been removed.  As the airplane goes up, the air pressing against the diaphragm lessens, allowing the diaphragm to expand.

The movement of the sides of the diaphragm move the hands on the face of the altimeter.

Still another kind of altimeter is called a radio or radar altimeter.  It measures altitude by sending radio signals to the ground.

It tells the altitude by measuring the time needed for the radio signals to reach the ground and bounce back to the plane. – Dick Rogers