A. Nitrogen - 78% - Dilutes oxygen and prevents rapid burning at the earth's surface.
need it to make proteins. Nitrogen cannot be used directly from the air.
The Nitrogen Cycle
is nature's way of supplying the needed nitrogen for living things.
B. Oxygen - 21% - Used by all living things.
Essential for respiration.
It is necessary for combustion or
C. Argon - 0.9% - Used in light bulbs.
D. Carbon Dioxide - 0.03% - Plants use it to make oxygen. Acts as a blanket and prevents the escape of
heat into outer space. Scientists are afraid that the buring of fossil fuels such as coal and oil are
adding more carbon dioxide to the atmosphere.
E. Water Vapor - 0.0 to 4.0% - Essential for life processes. Also prevents heat loss from the earth.
F. Trace gases - gases found only in very small amounts. They include neon, helium, krypton, and xenon.
Table of Contents ||
Past, Present, and Future ||
Up, Up, and Away ||