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WANGE
BERTE
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#1
pla
Back:
If you've ever let go of a helium-filled balloon
outdoors, you've already seen the first reason why
helium is a valued natural resource--it's lighter than
air. Helium's other claim to fame is that it is inert--it
doesn't burn or react with other materials.
Some of the practical uses of helium are just
variations on the party balloon. The blimp pictured
on the other side of this card is used by the U.S.
Customs Service for border surveillance in the war
on drugs, for example. Balloons filled with helium
are also used for weather research in the upper
atmosphere.
Because helium is an inert gas, the National
Archives in Washington, DC, uses it to provide a
safe atmosphere for preserving the original
Declaration of Independence and the U.S.
Constitution. NASA uses helium in the Space
Shuttle to pressurize the flow of liquid hydrogen fuel
to the main propulsion engines.
The most important source of helium is natural
gas, which usually contains less than 1% helium.
U.S. BUREAU OF MINES The Minerals Source
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