The Structure of the Atmosphere

I well remember a brilliant red balloon which kept me completely happy for a whole afternoon, until, while I was playing, a clumsy movement allowed it to escape. Spellbound, I gazed after it as it drifted silently away, gently swaying, growing smaller and smaller until it was only a red point in a blue sky. At that moment I realized, for the first time, the vastness above us: a huge space without visible limits. It was an apparent void, full of secrets, exerting an inexplicable power over all the earth’s inhabitants.

I. What is the function of the atmosphere? Water and nutrient cycles Regulates temperature Provides protection from sun Allows for life on Earth Solar energy interacts with the atmosphere to produce weather and climate.

II. What is the atmosphere made of? 78% Nitrogen Gas 21% Oxygen Gas (O2) 1% other-water vapor, argon, neon, helium, hydrogen, xenon, carbon dioxide, methane, nitrous oxide, ozone, particles (dust, soot), chlorofluorocarbons CO2 and H2O vapor play a critical role in regulating the amount of energy the atmosphere absorbs.

III. The Structure of the Atmosphere In order from the top down: Exosphere Thermosphere Mesosphere Stratosphere Troposphere The Sky Makes Thunder Emphatically!

A. The Troposphere The layer closest to the Earth’s surface. (Where you live!) Weather occurs and pollution collects here. Temperature decreases as altitude increases. Why? 9-16 km thick, varying from equator to poles.

B. The Stratosphere Contains the Ozone layer Ozone gas (O3) absorbs ultraviolet radiation from the sun to warm this layer About 12 to 50 Km thick (7-30 miles)

C. The Mesosphere Very thin air in this layer With lack of ozone, temperature decreases 50-80 km thick (30-50 miles)

D. The Thermosphere Very few gas molecules Temperatures increase due to absorption of intense solar radiation This leads to high temperatures(1000 °C), but low heat (molecules are sparse and widely spaced) Extends from elevation 80 km - 500 km

(Part of the thermosphere) The Ionosphere (Part of the thermosphere) Made of electrically charged particles called ions The aurora occur here when ions absorb energy from the sun Radio waves from earth reflect off the ionosphere back to earth

Outermost Layer D. The Exosphere Light gases (He & H) found here Molecule concentration decreases as you move upward to outer space Extends from about 500 km -700? km

Summary Diagram