Posted by: mrborden | November 20, 2011

Earths Early Atmosphere and Greenhouse Effect


Tue Nov 22
QFD: In all science, error precedes the truth, and it is better it should go first than last.
Hugh Walpole
?FD: Name the most abundant gas in our atmosphere?
Objective: 6b. Students know the global carbon cycle: the different physical and chemical forms of carbon in the atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs.
1) 200 pts 3 paragraph essay on the Greenhouse effect and Global warming (NB 623-626, OB 489, 525-526)
2) Ec 20 pts , write a letter to someone you respect or you think has helped you this year and give thanks ( teacher, soldier, parent, relative) – NOT ME

Have a safe Holiday!
Mon Nov 21
QFD: QFD: Leave the atom alone. E. Y. Harburg
?FD: Describe the term convection currents and give an example?
Objective: Ess d.* Students know the differing greenhouse conditions on Earth, Mars, and Venus;
the origins of those conditions; and the climatic consequences of each. History of Earths atmosphere
1) Notes/Lecture

Earliest atmosphere

The outgassings of the Earth were stripped away by solar winds early in the history of the planet until a steady state was established, the first atmosphere. Based on today’s volcanic evidence, this atmosphere would have contained 60% hydrogen, 20% oxygen (mostly in the form of water vapor), 10% carbon dioxide, 5 to 7% hydrogen sulfide, and smaller amounts of nitrogen, carbon monoxide, free hydrogen, methane and inert gases.[citation needed]

A major rainfall led to the buildup of a vast ocean, enriching the other agents, first carbon dioxide and later nitrogen and inert gases. A major part of carbon dioxide exhalations were soon dissolved in water and built up carbonate sediments.

Second atmosphere

Water-related sediments have been found dating from as early as 3.8 billion years ago.[17] About 3.4 billion years ago, nitrogen was the major part of the then stable “second atmosphere”. An influence of life has to be taken into account rather soon in the history of the atmosphere, since hints of early life forms are to be found as early as 3.5 billion years ago.[18] The fact that this is not perfectly in line with the 30% lower solar radiance (compared to today) of the early Sun has been described as the “faint young Sun paradox”.

The geological record however shows a continually relatively warm surface during the complete early temperature record of the Earth with the exception of one cold glacial phase about 2.4 billion years ago. In the late Archaean eon an oxygen-containing atmosphere began to develop, apparently from photosynthesizing algae which have been found as stromatolite fossils from 2.7 billion years ago. The early basic carbon isotopy (isotope ratio proportions) is very much in line with what is found today,[19] suggesting that the fundamental features of the carbon cycle were established as early as 4 billion years ago.

Third atmosphere
Oxygen content of the atmosphere over the last billion years
The accretion of continents about 3.5 billion years ago[20] added plate tectonics, constantly rearranging the continents and also shaping long-term climate evolution by allowing the transfer of carbon dioxide to large land-based carbonate storages. Free oxygen did not exist until about 1.7 billion years ago and this can be seen with the development of the red beds and the end of the banded iron formations. This signifies a shift from a reducing atmosphere to an oxidising atmosphere. O2 showed major ups and downs until reaching a steady state of more than 15%.[21] The following time span was the Phanerozoic eon, during which oxygen-breathing metazoan life forms began to appear.

Currently, anthropogenic greenhouse gases are increasing in the atmosphere. According to the Intergovernmental Panel on Climate Change, this increase is the main cause of global warming.[22]
from wikipedia.com
1) What is not a characteristic of the earliest forms of life?
a) they need carbon b) they need water c) they need oxygen d) they need nitrogen
2) Do the wavelenghths increase or decrease when solar radiation reflects off of earths surface?
3) What detrimental affect do CFC’s have on our environment?
4) Radiation can be used by? a) plants b) water c) soil d) none our used
5) Which would increase the greenhouse effect quicker? use of gasoline powered vehicles or eating more beef
6) how did oxygen get into our atmosphere?
7) If a person travels up a tall mountain, the pressure and temperature will? increase or decrease?
8) draw a picture of a sea breeze on a hot sunny day
9) Explain why there is more carbon in the air during the winter in the northern hemisphere than in the summer
10) About ____ % of solar radiation is absorbed at Earths surface?


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Responses

  1. i learned that the earth got oxygen by plants and their photo synthesis cycle.

  2. I learned that the longest chain of mountains in the world is in the ocean and is called the mid ocean ridge.

    • excellent! what type of boundary is it?


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