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Hole in the Sky. One is the Loneliest Number. Single oxygen atoms are unstable and want to combine with another atom or molecule. Two’s Company. Oxygen in our atmosphere is made of two oxygen atoms (O 2 ) and is very stable This is the most common form of oxygen in our atmosphere.
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One is the Loneliest Number • Single oxygen atoms are unstable and want to combine with another atom or molecule
Two’s Company • Oxygen in our atmosphere is made of two oxygen atoms (O2) and is very stable • This is the most common form of oxygen in our atmosphere
Three’s a Crowd • Ozone is made of three oxygen atoms (O3) and is less stable than O2 • It’s always trying to dump an oxygen to return to O2
Ozone Our Friend • Ozone and oxygen molecules in the stratosphere absorb ultraviolet light from the sun. • Together they absorb about 95 to 99% of the sun’s ultra violet radiation • Only ozone absorbs UV-C and UV-B radiation which can cause skin cancer, cataracts, wrinkles and weaken the immune system • Kills algae damaging marine life food chain
CFCs • CFC stands for chlorofluorocarbons • Because they contain chlorine, fluorine and carbon • CFCs were once thought to be one of the safest chemical compounds • Used for all kinds of products • Refrigerant, propellant for aerosol cans, foam rubber, chemicals for dry cleaning
A Growing Menace • Down in the troposphere CFCs are inert (which means they do not react with other chemicals) • The problem is that nothing breaks them down in the troposphere and they began to build up • As levels built up the began to drift up to the stratosphere
Ozone Under Attack • When CFCs enter the stratosphere they encounter ultraviolet radiation • UV rays unleash the monster in CFCs – chlorine • Chlorine rips off any extra oxygen atoms from ozone leaving behind O2 • An atom of chlorine in the stratosphere is like Pac-Man gobbling up of ozone molecules • A chlorine molecule could destroy 100,000 molecules of ozone
Antarctica Connection • Stratospheric clouds in Antarctica freeze solid into tiny flecks of ice • Chemicals that drift up into the stratosphere can land on a cloud and wait till sunlight returns the rip up the ozone
New Hole to the North • In 1988 a new hole over the Arctic was discovered • not as large as the hole over the Antarctic but this was enough to halt the production of CFCs • The “holes” in our sky are expected to worsen before they get better • It may take up to 100 years
This is not the story of global warming… • Many people confuse global warming and the hole in ozone but they are separate problems • Each with its own cause • But global warming could make the ozone hole worse • Global warming makes the atmosphere wetter which means more ice in the stratosphere