CAS ES 107 Chapter Notes - Chapter 3: Earth'S Energy Budget, Boiling Point, Inverse-Square Law
7 Jun 2018
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Chapter 3: Global Energy Balance (Part 1)
Goldilocks problem→ why is Venus too hot, Mars too cold, and earth just right?
-we want to say it’s because Earth lies at the perfect distance from the sun but it’s not just
the amount of sunlight received that determines a planet’s surface temperature
-the greenhouse effect also warms the planet and slows the amount of energy(heat) that
leaves
-without the greenhouse effect, Earth would be 33 C or 59 F colder (ball of ice)
-the sun (50% of its energy) emits only visible light (along with some UV and infrared) whereas
Earth emits infrared radiation
Electromagnetic radiation→ a self-propagating electric and magnetic wave that is similar to a
wave that moves on the surface of a pond
-in the form of light, ultraviolet, or infrared radiation
Wavelength→ distance between two adjacent crests
Frequency→ standing on one point of the wave…the amount of crests that passes in one second
-waves can be described by speed, wavelength and frequency
-the speed of the wave equals frequency times wavelength
-the longer the wavelength, the lower the frequency
*sometimes electromagnetic radiation can act more like a stream of particles rather than just a
wave
Photon→ a single particle, or pulse, of electromagnetic radiation
-the smallest independent amount of energy that can be transported by an electromagnetic
wave of a given frequency
-the energy of a photon is proportional to its frequency
-high frequency (short wavelength) photons have high energy
-when photons interact with matter, their energy is important
-high-energy photons can break molecules apart hence cause chemical reactions to occur,
whereas low-energy photons merely cause molecules to rotate faster or vibrate more
strongly
-this is called wave-particle duality
Electromagnetic spectrum→ the full range of forms of electromagnetic radiation, which differ
by their wavelength or frequencies
-visible light: measured in nanometers
a. color of lights depends on wavelength
b. the longest visible wavelength appears as red and the shortest looks blue
-infrared radiation: about 40% of the sun’s emitted energy
a. these wavelengths are significantly longer than visible light
b. measured in micrometers
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
We want to say it"s because earth lies at the perfect distance from the sun but it"s not just the amount of sunlight received that determines a planet"s surface temperature. The greenhouse effect also warms the planet and slows the amount of energy(heat) that leaves. Without the greenhouse effect, earth would be 33 c or 59 f colder (ball of ice) In the form of light, ultraviolet, or infrared radiation. The sun (50% of its energy) emits only visible light (along with some uv and infrared) whereas. Electromagnetic radiation a self-propagating electric and magnetic wave that is similar to a wave that moves on the surface of a pond. Frequency standing on one point of the wave the amount of crests that passes in one second. Waves can be described by speed, wavelength and frequency. The speed of the wave equals frequency times wavelength. The longer the wavelength, the lower the frequency.
