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LECTURE 36
     goals and outline

lecture title

    Quantum Physics in the Sky: Sunsets, Ozone, and the Greenhouse Effect

text pages

lecture goals

  • Learn some basic physical facts about the atmosphere.
  • Learn how the scattering of different colors (frequencies) of light at different angles determines the color of the sky.
  • Learn the energy level cascade process which converts higher energy (frequency) light into lower energy, for example UV photons into IR photons.
  • Relate which light gets scattered in which way in our atmosphere to "atomic fingerprints" (discrete spectra, such as those we saw in lecture with the plastic diffraction gratings).
  • Learn what ozone is, what it does for us, and why the ozone layer is eroding.
  • Learn what the greenhouse effect is, what it does for us, and why it is increasing.

outline of lecture

    1. Red Sky, Blue Sky

    2. Light Hits the Atmosphere

    3. Ozone

    4. Greenhouse Effect

quotes

Global change is more than the greenhouse effect and the ozone hole. Whilst changes in atmospheric composition present the largest single threat to environmental stability, that is only one aspect of the global change problem. The fundamental issue is that mankind is altering, in ways that are not well understood, virtually all the systems and cycles that together make life possible on Earth.

-- Global Change: Reducing Uncertainties, a publication of the International Geosphere--Biosphere Programme

The ultimate source of the energy that powers all living systems is, of course, the sun. The atomic basis of the enormous energy flow that makes life work is wonderfully simple: photons add energy to the electrons with which they collide, and plants have evolved a way of preventing the energized electrons in chlorophyll from instantly reemitting light and losing that energy. Instead the energized electrons are trapped and used to charge tiny subcellular batteries.

-- James L. Gould and Carol Grant Gould, in Life at the Edge, readings from Scientific American.

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Please email any questions, comments, or suggestions to Professor Bernice Durand, bdurand@theory3.physics.wisc.edu.

Revised November 30, 1997.


Content © 1997, Bernice Durand
Images and layout © 1997, Shane Hamilton