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The Quantum Physics of Your Toaster

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Half-hour mock class on the "ultraviolet catastrophe" and Planck's model of black-body radiation, delivered for an accepted students event at Union.

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The Quantum Physics of Your Toaster

  1. 1. US Library of Congress, LC-DIG-ggbain-35303 Anyone who is not shocked by quantum theory has not understood it. -- Niels Bohr
  2. 2. https://commons.wikimedia.org/wiki/File:Wiens_law.svg
  3. 3. http://commons.wikimedia.org/wiki/File:Max_Planck_1901.GIF
  4. 4. โ€œBlack-Body Radiationโ€ Absorbs all colors Model: Box with hole Tiny leak of light from inside
  5. 5. Pipe Organ, Bath Abbey (UK)
  6. 6. ๐œ†1 = 2๐ฟ ๐œ†2 = ๐ฟ ๐œ†3 = 2๐ฟ 3 ๐œ†4 = ๐ฟ 2 ๐œ† ๐‘› = 2๐ฟ ๐‘› Standing Waves
  7. 7. Wavelength (arb. units) 0.0 0.2 0.4 0.6 0.8 1.0 Numberofmodes 0 2 4 6 8 10
  8. 8. Wavelength (arb. units) 0.0 0.2 0.4 0.6 0.8 1.0 Numberofmodes 0 10 20 30 40 50 ๐œ† ๐‘› = 2๐ฟ ๐‘›
  9. 9. https://commons.wikimedia.org/wiki/File:Black_body.svg โ€œUltraviolet Catastropheโ€ (Rayleigh and Jeans)
  10. 10. โ€œBlack-Body Radiationโ€ Absorbs all colors Model: Box with hole Tiny leak of light from inside ๐œ† ๐‘› = 2๐ฟ ๐‘›
  11. 11. โ€œBlack-Body Radiationโ€ Absorbs all colors Model: Box with hole โ€œOscillatorsโ€ in walls produce light Oscillators have characteristic energy ๐ธ๐‘“ = โ„Ž๐‘“ โ„Ž = 6.626 ร— 10โˆ’34J-s ๏ƒจ โ€œPlanckโ€™s Constantโ€
  12. 12. โ€œBlack-Body Radiationโ€ Absorbs all colors Model: Box with hole Oscillators have characteristic energy ๐ธ๐‘“ = โ„Ž๐‘“ ๏ƒจ ONLY INTEGER MULTIPLES OF ๐‘ฌ ๐’‡ ALLOWED Quantum Hypothesis:
  13. 13. 6 quanta 3 quanta 2 quanta 1 quantum 0 quanta http://commons.wikimedia.org/wiki/File:Max_Planck_1901.GIF Energy:
  14. 14. https://xkcd.com/54/ http://hyperphysics.phy-astr.gsu.edu/hbase/bkg3k.html#c6
  15. 15. https://commons.wikimedia.org/wiki/File:Max_Planck_1933.jpg Planck in 1933
  16. 16. http://commons.wikimedia.org/wiki/File:Einstein_patentoffice_full.jpg
  17. 17. ๐ต ๐œˆ, ๐‘‡ = 2โ„Ž๐œˆ3 ๐‘2 1 ๐‘’โˆ’โ„Ž๐œˆ/๐‘˜ ๐ต ๐‘‡ โˆ’ 1

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