Download Climate Change

Climate Change
Entry Lesson
Planetary Temperatures Activity
SC.912.E.7.7
Identify, analyze, and relate the internal (Earth system) and
external (astronomical) conditions that contribute to global
climate change.
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Essential Questions
•
What factors determine the average
temperature of a planet?
•
In what ways can you describe how
the earth is heated?
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http://commons.wikimedia.org/wiki/File:Thermometer_0.svg
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Extension Question
How can you relate
o
internal (planetary system)
– and
o
external (astronomical)
conditions of Earth’s global climate
change to at least 1 of the other inner
planets?
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http://wardssciencewiki.wikispaces.com/file/view/composite_earth
1_red.gif/162969781/composite_earth1_red.gif
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Electromagnetic Spectrum
•
Photons: packets of energy
o
Have no mass
o
Can travel through space
o
Travel along wave paths
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https://www.flickr.com/groups/pilipinas/discuss
/72057594124976565/
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Radiation can be reflected, scattered, or absorbed
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http://www.eco-info.net/what-aregreenhouse-gases.html/reflection
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Planetary Temperature
•
How does the average temperature of a planet depend on
its distance from the sun?
•
•
Simple model

Input: From the sun

Output: Radiation of a heated object
Analysis

Equilibrium: Input = Output

D=distance from sun, T=average temperature

Create a combination of D & T that is a constant

Use data to see how close each planet is to the same constant.
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6
Design a Model to Simulate Solar
Radiation
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Photo: credit: Terri Pope-Hellmund
6/16/2014 Orlando, FL FRC-STEM
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Collect Data
Model Planet
Name
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Distance from
Heat Source
cm
Equilibrium
Temperature
Degrees
Celsius
Input
•
Let S=total power (energy produced/time) of the sun (S ~
4x1026 watts)
•
This power passes through the surfaces of all spheres of
that orbit the sun with radius R centered at the sun.
•
•
The surface area of a sphere =4πR2.
•
Note: Same “inverse square law” applies to gravitational
Power/Area = Intensity = S/4πR2
attraction, spatial variation of sound and light intensity.
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Input Intensity = S/4πR2
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Output
•
•
Radiation of heat from the object
Common approximation: treat the planet as a “black
body”: Intensity = aT4

T: temperature (measured from absolute zero)

A: constant
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Solar Input & Radiative Output
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Equilibrium: Solar
Input=Radiative Output
•
•
•
•
S/4πR2 = aT4
(S/4πa) = R2T4
Model Prediction: RT2 = constant (all R).
Test prediction: Measure R and T for various planets and note
whether the prediction is valid.
•
Create a bar graph showing RT2 for each planet
PREDICTIONS?????
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Predict temperatures for planets
Planet Name
Mercury
Venus
Earth
Mars
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Average
Distance from
Sun
Astronomical
Units
.39
Average
Temperature
Degrees
Kelvin
400
Inner Planet Data
Planet Name
Average
Temperature
Degrees
Kelvin
Mercury
Average
Distance from
Sun
Astronomical
Units
.39
Venus
.72
730
Earth
1.00
280
Mars
1.52
213
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400
•
Excel Model
450000
400000
Venus
350000
300000
250000
200000
150000
100000
50000
Mercury
Earth
Mars
3
4
0
1
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2
Closure: Planetary Temperatures
1. What determined the temperature of your planets?
2. Did your planets come to an equilibrium temperature? What is
happening at that temperature?
3. If your sun got hotter, would the temperature change? How?
4. If your planet got farther away, would the temperature change?
How?
5. What conclusion can you draw when analyzing your model data
and the actual measurements for the inner planets?
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Inner Planets
http://evansscienceblog.blogspot.com/2012/02/innerplanets.html
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