Brendans+Notes+and+Research

= =

__**Notes and Research**__ toc =The Greenhouse Effect(revised):= The "Greenhouse Effect" refers to how certain atmospheric gases (CO2, methane) can allow the visible light from the sun to reach the Earth's surface, but will trap the infrared light that the Earth then radiates back out. This leads to an accumulation of heat on Earth.

=Goldilocks= The Earth, Venus and Mars are three planets that are well situated to benefit from the energy output of the sun, yet all 3 have very different atmospheres and surface conditions. Scientists who first probed the potential of increased greenhouse gases effects on Earth’s climate looked for clues about our future by examining the conditions on our nearest neighbors. Complete this table. //Be sure to include a complete reference and URL for any sources you use to find the necessary information//.


 * Atmospheric Gas || Venus || Earth || Mars ||
 * Carbon Dioxide ( percent || 96.5% || 0.03% || 95.32% ||
 * Nitrogen (N2) || 3.5% || 78.08% || 2.7% ||
 * Oxygen (O2) || Trace || 20.95% || 0.13% ||
 * Argon (Ar) || .0007% || 0.93% || 1.6% ||
 * Methane (CH4) || 0 || .000179% || 0 ||
 * Surface Pressure – Relative to the Earth ( in bars) || 90 || 1 (duh) || .000636 ||
 * Major Greenhouse Gases (abbreviated to GHG) || CO2 || H2O, CO2 || CO2 ||
 * Actual temperature © || Between 13 &465 || 15 || Between -200 &- -40 ||
 * Temperature if no GHG © || -46 || -18 || -57 ||
 * Temperature due to GHG ( C) || +523 || +33 || +10 ||

The findings of scientists review evidence about the three planets is often referred to as the “Goldilock’s Principle” after the Fairytale character of that name’s response to each of the items she found in the three bears home while they were out for a walk. Missing from the table is information about the difference in surface pressures on each of the planets that account for the “amount” of atmosphere that is found on each. Compared to Earth, Venus has 90 times the surface pressure while Mars has 0.007 times the pressure. From examining the contents of the completed table, what do you think explains the differences between Earth and its neighboring planets?

According to the table, I see 2 main factors that explain the differences between Venus, Earth, and Mars. These factors are the composition of the atmosphere and the distance from the sun. Mars is very far from the sun and has very little atmosphere, so even if it is mostly CO2, it can’t trap much heat, leading to the frozen landscapes. Venus isn’t much closer to the sun than Earth, but it has so much CO2 that it must trap the gas and cause the extreme temperatures. This makes me wonder what effect Nitrogen has on temperature…. It hasn’t been mentioned as a greenhouse gas…

Mars; Journey Through the Galaxy, 9-14-06. Used 8-30-10. []

Venus; Journey Through the Galaxy, 9-14-06. Used 8-30-10. []

=Questions 1&2 pg 17.=

1. 1W=1J/s 100W=100J/s. __100j 60s 60min 24hr__ = __8,640,000j 30,000,000j 30__ = __9,000,000j 8,640,000__ = 0.96 kg of coal. s 1min 1hr 1day day kg of coal 100 kg of coal 9,000,000 It takes 0.96 kilograms of coal to power one 100watt lightbulb for an entire day.

2. Corn in North America is planted in May and harvested in October, so the growing season is about 5 months, or 150 days. I would guess that there are roughly 30 ears of corn in a square meter (I asked a Nebraskan friend but he didn't know). __one calorie 250 joules 60 seconds 60 minutes 24 hours 150 days__ = 774,008,600 calories 4.186joules second one minute one hour one day growing season growing season So a square meter of ground receives about 775 million calorie's worth of energy per 5 months. 30 ears of corn at 140 kilocalories per ear would be 2,240,000 calories worth of energy.

4,200,000 = 0.5% efficiency. 774,008,600

This massive discrepancy between energy sent and energy saved can be accounted for by the two following facts: corn does not cover every single square centimeter of the land it grows in, so a large percentage of the sun's energy may not reach the plant at all. Also, corn has to build the stalk, the leaves, the roots, etc; all of which require energy.

Corn, Planting and Harvesting Seasons, Chuck Kowalksi. Updated 2010, used 8-31-2010 http://commodities.about.com/od/researchcommodities/a/corn-seasons.htm Corn on the Cob, Food Details, updated in 2010, used 8-31-2010. http://caloriecount.about.com/calories-lowes-foods-corn-cob-i120209

Chapter 3: Bare Rock Model Questions
1) What does Fin = Fout mean in this model. Use your own words Fin refers to the energy entering Earth, almost all of which comes from the sun as visible light. Fout refers to the energy leaving earth, mostly either as reflected visible light or emitted infrared.

2) Why do you measure the size of the shadow cast by the Earth when the Sun shines on it to calculate the intensity of the energy heating the Earth? Because not all of the earth's surface is hit by the sun's energy at any one moment. Nor is half of the surface area hit either, since objects cast shadows. Measuring the sized of the shadow gives the area of the light that was blocked and therefore absorbed or reflected. Once you have that area and a few other bits of information, you can calculate the intensity.

3) Show the calculations to determine the temperature of Venus and Mars using the data in TABLE 3.1. Are these the measured temperatures on Venus and Mars? Why or Why not? I tried to paste these directly into the wiki... no luck. Hopefully this link will work. (216.665665 degrees kelvin) (240.1188913 degrees kelvin) These are not the measured temperatures for Mars or Venus. According to the chart, Venus should be 460 degrees hotter (kelvin) while Mars should be 24 degrees hotter (also kelvin). This difference is to be expected since this model does not take into account many, many variables. The most notable missing variable is the lack of an atmosphere/any greenhouse gases. This would decrease the Fout significantly, allowing the temperature to increase.

=Chapter 3 part 2= Well, the equation for the atmosphere is Amount of Energy going Up from the Atmosphere plus the amount of energy heading down to the ground from the atmosphere is equal to the amount of energy that the ground radiates. The equation for the ground is The amount of Energy entering from space + the amount of energy coming down from the atmosphere is equal to the amount of energy that the ground radiates. Since both equations have "equal to the amount that the ground radiates", we know that they are interchangeable. Therefore, the Amount of Energy going Up from the Atmosphere plus the amount of energy heading down to the ground from the atmosphere is equal to The amount of Energy entering from space + the amount of energy coming down from the atmosphere. If you subtract the "Amount of energy heading down to the ground from the atmosphere" from both sides, you end up with the Amount of Energy going Up from the Atmosphere is equal to The amount of Energy entering from space. This is the exact same as the budget for the earth overall.
 * Read the remainder of Chapter 3. Answer the following questions on your wiki page in “Research and Notes” section.**
 * 1. Verify, in your own words and, if you would like, with a diagram, that the budget equation for the layer model of the earth’s overall energy is equal to the sum of the budget equations for the ground and the atmosphere. Why is it important that this be true for our model calculations? (See explanation between pages 23 and 25).**

**2. 2. What is the “skin temperature” of the Earth, and why is it significant to the development of the layer model?** The "skin temperature" is the temperature of the layer where IR from Earth is no longer absorbed by the atmosphere. This means that past the skin, the energy is lost to Earth. It is significant to the Layer Model because it must be equal to the amount of incoming radiation if the amount of energy on Earth is to remain stable.

Assuming that the Intensity of incoming energy for the moon is almost exactly the same as it is for the earth (1350 w/m-squared), and with the knowledge that the moon's albedo is 0.12. (http://www.asterism.org/tutorials/tut26-1.htm), the Bare Rock formula puts the moon at 269 degrees kelvin, or about -4 degrees celsius. A casual google search puts the temperature in the range of about 40 degrees celsius. So either the intensity of the solar energy is significantly greater for the moon of there is some sort of greenhouse effect going on there. On the dark side of the moon, assuming a perfect blackbody and no heat transfer, the temperature would be 0 degrees kelvin, since all energy would radiate back out into space.
 * 3. 3. Respond to question #1 on page 27 **

=Daisyworld Questions=