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18 Cards in this Set

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Troposphere

The layer closest to Earth, where almost all weather occurs; the thinnest layer (0-16 km)

Stratosphere

The layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases; the ozone is also found here (50 km)

Mesosphere

The middle layer of Earth's atmosphere; the layer in which most meteoroids burn up; contains stars; the coldest layer of the atmosphere (80 km)

Thermosphere

the upper most atmospheric layer. Gets warmer w/ altitude. temperature varies most. Satellites. (400 km)

Exosphere

Farthest layer from earth. Atmosphere meets space, molecules drift into space. (640- 64000 km)

What is the atmosphere composed of?

Oxygen- 21%


Nitrogen- 78%


Argon- 0.9%


Co2- 0.037%

Why is the atmosphere important?

It protects life on planet earth. Protect from UV rays allowing life to exist.

CFC

Chlorofluorocarbons. Found in AC's, refrigeratos, aerosol cans, (bug spray) Styrofoam). Breaks down ozone (opens whole in the ozone layer). Does not degrate. Circulates for 50 years.

CFC Formula

CCl3F--> Cl+ CCl2F


Cl+O3--> ClO + O2


ClO+O--> Cl+O2

Halocarbons/Halons

Ozone depleting chemical. Found in:


Fire retardant, Soil fumigant/ pesticides (methyl bromide), solvents, Foam-blowing insulation.

Depletion of the ozone layer

Depletion greatest at the poles, but occurs worldwide.


Is seasonal (thinnest in winter)


- Aug-Nov (Southern)


-Jan-April (Northern).


Cold weather conditions create ideal weather conditions (ice crystal) to catalyze more destruction of the ozone.

Increased amount of UV radiation reaches surface

Harmful to Cell


Decrease photosynthetic activity


Skin Cancer


Eye cataracts


Damaged immune system



Montreal Protocol (1987)

Most far reaching environmental treaty. Require elimination of CFC production; use in developed world by 1996.


Concentrations of CFCs are decreasing


Reboot in 1992 with Copenhagen protocol.


Aimed to reduce excess skin cancer cases and effective stratospheric chlorine by decreasing CFC's production.

Precambrian

Eon: Proterozoic, Archean, Madean.


How old: 4.5 billion years ago


Major events:


- Water forming


- Early samples of life


- Only invertebrates


- 88% of Earth's history

Paleozoic

Eon: Phanerozoic


How old: 500 MA


Major events:


- First vertebrates


- Supercontinent breaks-up


- Plants

Mesozoic

Eon: Phanerozoic


How Old: 66-250 Ma ago


Major Events:


- Pangea joined and separated


- Dinosaurs


- Archosaurs



Cenozoic

Eon: Phanerozoic


How old: 65 MA


Major Events:


- Right after dinosaur extinction


- Mammals began


- 3 periods.

Time unites used to measure geologic time scale (from largest to smallest)

years, periods, era,eon