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Learn about the step-by-step process of how the Earth's atmosphere was formed, including the primordial atmosphere, outgassing, comet bombardment, and the presence of water.
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Warm Up: Friday 2/10/12 pg 42-43 NB Origin of Atmosphere Obj: TSWBAT describe the origins of the atmosphere by drawing the process step by step. Homework: Notebook Due Friday (p24-50=165 points) Warm Up (use complete sentences) What are the layers of the atmosphere starting with closest to the earth? Which layer is responsible for the weather?
Table of Contents Date: Title: Page: 2/9/12 Intro to Atmosphere Notes 48 2/9/12 Layers of ATM page 1 49 2/9/12 Layers of ATM page 2 50 2/10/12 Origin of ATM notes 51 2/10/12 Origin of ATM Step by Step Guide 52 Agenda: finish layers of atmosphere, notes on origin of atm, step by step guide
Primitive Atmosphere • *Primordial atmosphere: Earth’s original atmosphere; probably made of hydrogen and helium • *Solar wind: stream of energized particles, or plasma, flowing outward from the Sun • *Solar winds drove the first atmosphere away
Outgassing • *The atmosphere was then replaced by outgassing and materials from comets. • *outgassing: the outpouring of gases from the earth's interior (volcanoes!!) • *Other gases were released into the atmosphere: (write all) • water vapor • carbon dioxide • Nitrogen • Chlorine • Hydrogen
Comet Bombardment • *Comet: a small, icy mass in the Solar System; its nucleus is made of ice, dust, and rocky particles • Comets come from the outer reaches of space at great speeds. When a comet collides with the Moon, the explosion is so powerful that it creates a large crater, and the material itself shoots out into space again. The collision leaves nothing other than the crater. • *On Earth, some of the comets’ material remains, because the Earth has a stronger gravitational force • *Consequently water from the comets would stay on the Earth due to GRAVITY!
The Early Atmosphere • *outgassing and comet bombardment caused a new atmosphere to form • *the presence of water changed the atmosphere: • Original=methane and ammonia • New=nitrogen, hydrogen, and carbon dioxide.
The Early Atmosphere • *As Earth cooled, the water vapor in the new atmosphere condensed. • *As a result of the Earth cooling, it rained, filling the depression we call our oceans.
Present Day Atmosphere • *as the atmosphere developed, photosynthesis began by primitive cyanobacteria • *carbon dioxide was taken up by plants, and oxygen was released. • *The present balance of gases in the atmosphere was achieved at least 600 million years ago.
Present Day Atmosphere • *Small changes in the amount of carbon dioxide in the atmosphere have occurred naturally since then. • **Significant increases have been measured in modern times and attributed in large part to human activities, such as the burning of fossil fuels.