Global temperature lab
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Indian River State College *
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1005
Subject
Geography
Date
Feb 20, 2024
Type
docx
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4
Uploaded by ProfessorDonkey1478
Shayla Pimentel U12A2: Greenhouse Gases and Average Global Temperature
Purpose:
The purpose of this lab is to investigate how the greenhouse gases and cloud cover affects Earth’s average global temperature.
Background:
Earth’s atmosphere is made of up many gases, mostly nitrogen N₂ and oxygen O₂ gases, but also carbon dioxide CO₂, water vapor H₂O, and methane CH₄, among other compounds. Gases that absorb and reemit infrared light are greenhouse gases. Gases that do not interact with infrared light are not greenhouse gases. The greenhouse effect
makes temperatures favorable for life on Earth but makes other planets, like Venus, uninhabitable.
Albedo
is the fraction of light that a surface reflects. A surface that reflects 100% of light has an albedo of 1, while a surface that absorbs 100% of light has an albedo of zero.
Instructions:
For each part, follow the instructions to set up each scenario in the simulation and answer the corresponding questions. You may type your answers. This is scored based on completion. Part 1: Greenhouse Gases
Go to https://phet.colorado.edu/sims/html/molecules-and-light/latest/molecules-
and-light_all.html
In this simulation, you will observe how different wavelengths of the electromagnetic spectrum interact with different molecules of gas. Try passing photons of infrared and visible light through molecules of each of the
gases listed in the table below. Describe the interaction for each.
Gas
Visible
Infrared
Nitrogen
Nitrogen and oxygen both show visible light transparency. They don't interact or absorb any visible light.
Nitrogen and oxygen are generally transparent to infrared light.
Oxygen Oxygen allows visible light to flow through it. It has minimal absorption or interaction effects on light in
the visible range, which includes colors ranging from
No visible amount of oxygen in the earth's atmosphere absorbs infrared radiation. It is transparent for most of the infrared wavelengths.
violet to red.
Carbon Dioxide
Carbon dioxide is transparent to visible light. Carbon dioxide absorbs a substantial amount of infrared light. It absorbs energy at specific infrared wavelengths.
Methane
Methan is transparent to visible light.
Methane is a powerful absorber of infrared radiation, particularly
in certain wavelengths.
Water
Due to water vapor absorbing some visible light,
particularly in the red region
of the spectrum, it adds to the earth's greenhouse effect.
Water vapor contributes to the greenhouse effect by being a significant absorber of infrared energy.
1.
Based on your observations, which gases are greenhouse gases.
Water Vapor, Carbon Dioxide, and Methane. The remaining parts of the lab, you will use the following simulation.
https://phet.colorado.edu/sims/html/greenhouse-effect/latest/greenhouse-
effect_en.html
. Part 2: The Greenhouse Effect on Earth Click on the Photons module. Set the greenhouse gas concentration to none.
Uncheck Cloud
. Start Sunli
ght and let the simulation run until the surface temperature stabilizes.
1.
With no greenhouse gases in the atmosphere or no clouds, what is the temperature at the surface of the Earth? At -9.3 degrees Celsius, the Earth's surface temperature is stable. Slowly move the greenhouse gas concentration slider upward and stop at the
middle.
2.
Observe the behavior of the infrared photons. Explain what is happening.
Less infrared light is reflected into the atmosphere and more is absorbed by the surface.
3.
When the slider is in the middle, what is the surface temperature? How does this compare to the temperature when there are no greenhouse gases present. At 10.4 degrees Celsius, the surface temperature is much higher than it would be in the absence of greenhouse gases.
4.
An increase in greenhouse gas concentration leads to a(n) (
increase
or decrease
) in surface temperature.
Surface temperatures rise in response to increases in greenhouse gas concentrations.
Complete the table below by running the simulation for the remaining time periods.
Time Period
Greenhouse Gas Concentrations
Temperature
CO
₂
CH
₄
N
0
₂
Ice Age
180 ppm
380 ppb
215 ppb
7.5 C
1750
277 ppm 694 ppb
271 ppb
13.6 C
1950
311 ppm
1116 ppb
288 ppb
13.7 C
2020
413 ppm 1889 ppb 333 ppb 14.9 C
5.
From the Ice Age to 2020, how much did the global average temperature change? Based on the table above, what was one of the contributing factors to this temperature change?
Due to a rise in greenhouse gases, the average global temperature rose by 7.4 degrees Celsius between the Ice Age and 2020.
Part 3: Effect of Clouds on Temperature Reset the simulation. Again, start with the greenhouse gas concentration at zero. This time check Cloud in order to simulate the presence of clouds. Start Sunlight
. Allow the surface temperature to stabilize. 6.
How are the sunlight photons interacting with the cloud? Sunlight photons are bouncing off the cloud, reflecting sunlight back into space.
7.
How are the infrared photons interacting with the cloud?
The infrared photons are traveling through the cloud without engaging with it in any way.
8.
Did the surface temperature increase, decrease or stay the same? (compare to the temperature in Part 2 Question #1)
In contrast to the temperature in Part 2 Question #1, the surface temperature dropped. Because the cloud reflects sunlight, the earth's surface receives less heat.
For the following questions, use the internet to research.
1.
How can clouds affect surface temperature on a local scale
during the day?
What about at night? On a local scale, clouds can both raise and lower surface temperatures. Because high level cloud cover keeps heat from escaping, it warms the surface. The simulation
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demonstrated that low-level clouds reflect sunshine photons, causing the surface to cool. Clouds trap heat from the sun at night, covering the surface of the Earth like a blanket.
2.
What is the net effect of cloud cover on Earth's global temperature today?
My research indicates that the Earth's surface is currently cooling by roughly 5 degrees Celsius because of cloud cover.
Closing Questions:
3.
Explain how the greenhouse effect works at Earth’s surface IN YOUR OWN WORDS.
As heat is trapped in the atmosphere, the greenhouse effect raises the temperature of the Earth's surface.