Lect17 -- Solar

06 0158 016 wind 0036 0040 0108 011 1168

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Unformatted text preview: / 0.077 0.063 / 0.06 0.158 / 0.16 Wind 0.036 / 0.040 0.108 / 0.11 1.168 / 1.20 Total 6.351 /7.18 6.15 / 6.3 9.135 / 9.39 much room for improvement/growth, but went backwards from 1994 to 2003! Table from Tom Murphy, UCSD Energy from the Sun reaches Earth as light But what is light? Empedocles, 5th Century BC in Greece Light is a fire within the human eye Lucretius, 55BC in Rome Light is minute atoms Faraday and Maxwell (late 19th Century): light as a electromagnetic wave Planck (1900): quantum mechanical view of “photons” as both particle and wave (“wave packets”) Light as photons Photons are “wave packets” of electromagnetic energy •  travel at the speed of light in a vacuum •  behave like particles and like waves •  we focus on wave-like properties. Wave properties of electromagnetic energy Electromagnetic radiation: oscillating electrical and magnetic fields that propagate through space figure from wikipedia.org λ = wavelength Red f = frequency light wavelength c = speed of light = (frequency)*(wavelength) The electromagnetic spectrum: variability in photon energy The electromagnetic spectrum: 700 nm 650 nm Red 600 nm Orange Radio Waves Micro Waves 100 1 550 nm Yellow Infrared 10 -2 500 nm Green Visible 10 -4 450 nm Blue Ultra Violet 10 -6 X-Rays 10 -8 400 nm Violet Gamma Rays 10 -10 Wavelength (cm) Photon energy increases with increasing frequency Photon Energy = (Plank's constant)*(frequency) = h*f Black body (idealized) radi...
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