Please complete the following questions.

Lab # 10.Greenhouse Effect

Objectives

• Analyze how Greenhouse Gases affect Earth's temperature
• Identify processes that might increase or decrease Earth's temperature

Theory

Table 1:Average composition of the Earth's atmosphere up to an altitude of 25 km.
Gas Name	Chemical Formula	Percent Volume
Nitrogen	N2	78.08%
Oxygen	O2	20.95%
*Water	H2O	0 to 4%
Argon	Ar	0.93%
*Carbon dioxide	CO2	0.0360%
Neon	Ne	0.0018%
Helium	He	0.0005%
*Methane	CH4	0.00017%
Hydrogen	H2	0.00005%
*Nitrous oxide	N2O	0.00003%
*Ozone	O3	0.000004%

CH₄ is a very strong greenhouse gas. Since 1750, methane concentrations in the atmosphere have increased by more than 150%. The primary sources of the additional methane added to the atmosphere (in order of importance) are: rice cultivation; domestic grazing animals; termites; landfills; coal mining; and, oil and gas extraction.

The volume of CO₂has increased by over 35% in the last three hundred years. This increase is primarily due to human activities such as the combustion of fossil fuels, deforestation, and other forms of land-use change. It is now factthe increase is causing global warming through an enhancement of the greenhouse effect.

H₂0(water vapor)varies in concentration in the atmosphere both spatially and temporally. Water vapor has several very important functional roles on our planet. For example, thecondensation of water vapor creates precipitation that falls to the Earth's surface providing needed fresh water for plants and animals. Additionally, it helps warm the Earth's atmosphere through thegreenhouse effect.

N₂is removed from the atmosphere and deposited at the Earth's surface mainly by specialized nitrogen fixing bacteria, and by way oflightning throughprecipitation. The addition of this nitrogen to the Earth's surfacesoils and various water bodies' supplies much-needed nutrition for plant growth.

O₂ is exchanged between the atmosphere and life through the processes of photosynthesis and respiration. Photosynthesis produces oxygen when carbon dioxide and water are chemically converted into glucose with the help of sunlight.

Remember, infrared radiation is heat.

Materials and Methods

List all objects and apparatus used.

Procedure

1. Website: http://phet.colorado.edu/en/simulation/greenhouse.Click on "Run Now" to run the simulation.
2. Click on Today, "1750", Ice Age on the right side of the screen to set the atmosphere to the proportions for that date. Wait a few minutes for the temperature to stabilize.
3. Record the composition of the atmosphere (on the right side of the screen) and the temperature on the thermometer
4. Fill the Table 1.
5. Click on the "Photon Absorption" tab at the top of the screen.
6. Use the buttons on the right side of the screen to test different molecules.Record your observations in the Table2.Write "yes" if any photons get absorbed; write "no" if no photons get absorbed.
7. Click on the "Glass Layers" tab at the top of the screen. On the right side of the screen, set the Number of Glass Panes to "1". Answer the relevant analysis questions.

Data

Table 1.

	Today	1750	Ice Age
H2O (water vapor)
CO2 (carbon dioxide)
CH4 (methane)
N2O (nitrous oxide
C (degrees Celsius)

Table 2. Which gases absorb photons?

	Infrared Photons	Visible Photons
CH4 (methane)
CO2 (carbon dioxide)
H2O (water vapor)
N2 (nitrogen)
O2 (oxygen)

analysis

1. What do the yellow dots moving down represent?

1. What do the red dots represent?
2. Do the red dots all move upwards?
3. Watch the yellow photons carefully. Do they pass through the glass or are they blocked?
4. Watch the red photons carefully. Do they pass through the glass or are they blocked?
5. Which three gases contribute to the greenhouse effect in our atmosphere?
6. Which two gases do NOT contribute to the greenhouse effect?
7. Describe how the Greenhouse Gases affected Earth's atmosphere during the Ice Age, the year 1750 and Today.

1. What would happen if there were no Greenhouse gases? (Adjust the Greenhouse Gas Concentration Level to None.)

1. What would happen if Greenhouse gases increase? (Adjust the Greenhouse Gas Concentration Level to Lots.)

Conclusion

Identify some natural or human processes that might increase or decrease the amount of greenhouse gases in the atmosphere.