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The nature of

The nature of. …and a history of our attempt to understand it. Early 1600’s Galileo and the speed of light…. People were saying in the early 1600’s that it took no time for light to travel any distance (speed of light = infinite). Galileo thought otherwise.

jared-mason
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The nature of

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  1. The nature of …and a history of our attempt to understand it.

  2. Early 1600’s Galileo and the speed of light… People were saying in the early 1600’s that it took no time for light to travel any distance (speed of light = infinite). Galileo thought otherwise. Image and info acquired at http://www.colorado.edu/physics/2000/waves_particles/lightspeed_evidence.html through www.google.com.

  3. Early 1600’s Galileo and the speed of light… People were saying in the early 1600’s that it took no time for light to travel any distance (speed of light = infinite). Galileo thought otherwise. Image and info acquired at http://www.colorado.edu/physics/2000/waves_particles/lightspeed_evidence.html through www.google.com.

  4. Early 1600’s Galileo and the speed of light… People were saying in the early 1600’s that it took no time for light to travel any distance (speed of light = infinite). Galileo thought otherwise. Unfortunately for Galileo, light travels a mile in about .000005 s. Image and info acquired at http://www.colorado.edu/physics/2000/waves_particles/lightspeed_evidence.html through www.google.com.

  5. 1676 and Olaus Rømer… Rømer was a Danish astronomer who spent some time observing the motion of Io, one of Jupiter’s moons. He noticed that some of Io’s eclipses appeared earlier or later than expected. Images acquired at http://en.wikipedia.org/wiki/Olaus_Romer, and http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/30/ through www.google.com.

  6. 1676 and Olaus Rømer… Rømer was a Danish astronomer who spent some time observing the motion of Io, one of Jupiter’s moons. He noticed that some of Io’s eclipses appeared earlier or later than expected. Then he realized that this was because of the Earth’s position. (see sketch) Images acquired at http://en.wikipedia.org/wiki/Olaus_Romer, and http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/30/ through www.google.com.

  7. 1676 and Olaus Rømer… Rømer was a Danish astronomer who spent some time observing the motion of Io, one of Jupiter’s moons. He noticed that some of Io’s eclipses appeared earlier or later than expected. Then he realized that this was because of the Earth’s position. (see sketch) Images acquired at http://en.wikipedia.org/wiki/Olaus_Romer, and http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/30/ through www.google.com.

  8. 1676 and Olaus Rømer… Rømer was a Danish astronomer who spent some time observing the motion of Io, one of Jupiter’s moons. He noticed that some of Io’s eclipses appeared earlier or later than expected. Then he realized that this was because of the Earth’s position. (see sketch) Measured c to be about 220,000,000 m/s. Images acquired at http://en.wikipedia.org/wiki/Olaus_Romer, and http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/30/ through www.google.com.

  9. 1850 Fizeau and Foucault Images acquired at http://laser.phys.ualberta.ca/~egerton/c&ether.htm and http://geocities.yahoo.com.br/saladefisica3/ through www.google.com.

  10. 1850 Fizeau and Foucault Images acquired at http://laser.phys.ualberta.ca/~egerton/c&ether.htm and http://geocities.yahoo.com.br/saladefisica3/ through www.google.com.

  11. 1850 Fizeau and Foucault Images acquired at http://laser.phys.ualberta.ca/~egerton/c&ether.htm and http://geocities.yahoo.com.br/saladefisica3/ through www.google.com.

  12. 1850 Fizeau and Foucault Images acquired at http://laser.phys.ualberta.ca/~egerton/c&ether.htm and http://geocities.yahoo.com.br/saladefisica3/ through www.google.com.

  13. 1850 Fizeau and Foucault Measured c to be about 300,000,000 m/s. Images acquired at http://laser.phys.ualberta.ca/~egerton/c&ether.htm and http://geocities.yahoo.com.br/saladefisica3/ through www.google.com.

  14. 1704 and Isaac Newton REFRACTION Light is made of a bunch of little “corpuscles.” (particles) Image acquired at http://msp.rmit.edu.au/Article_04/02.html and http://microcosmos.uchicago.edu/microcosmos_new/newton/glassworks/ and http://scv.bu.edu/~aarondf/avgal.html through www.google.com.

  15. 1801 and Thomas Young Light is a wave. Images acquired at http://www.fau.edu/~jordanrg/bios/Young/Young_bio.htm and http://www.cavendishscience.org/phys/tyoung/tyoung.htm and http://www.museum.vic.gov.au/scidiscovery/light/index.asp and http://nobelprize.org/physics/articles/ekspong/ through www.google.com.

  16. Mid 1800’s and Michael Faraday Experimental Researches on Electricity (1839–55) Image and info acquired at http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0001235.html and http://dspt.club.fr/FARADAY.htm and http://www.cartref.demon.co.uk/eng/boe20b.jpg through www.google.com.

  17. Mid 1800’s and Michael Faraday Experimental Researches on Electricity (1839–55) Image and info acquired at http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0001235.html and http://dspt.club.fr/FARADAY.htm and http://www.cartref.demon.co.uk/eng/boe20b.jpg through www.google.com.

  18. Mid 1800’s and Michael Faraday Experimental Researches on Electricity (1839–55) So, a changing magnetic field makes an electric field… Image and info acquired at http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0001235.html and http://dspt.club.fr/FARADAY.htm and http://www.cartref.demon.co.uk/eng/boe20b.jpg through www.google.com.

  19. Mid 1800’s and Michael Faraday Experimental Researches on Electricity (1839–55) So, a changing magnetic field makes an electric field… Image and info acquired at http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0001235.html and http://dspt.club.fr/FARADAY.htm and http://www.cartref.demon.co.uk/eng/boe20b.jpg through www.google.com.

  20. James Clerk Maxwell and the 60’s (the 1860’s) Images acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://home.usit.net/~cmdaven/electro.htm and http://micro.magnet.fsu.edu/primer/java/electromagnetic/ through www.google.com.

  21. James Clerk Maxwell and the 60’s (the 1860’s) If a changing magnetic field makes an electric field (or current), wouldn’t a changing electric field make a magnetic field? Images acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://home.usit.net/~cmdaven/electro.htm and http://micro.magnet.fsu.edu/primer/java/electromagnetic/ through www.google.com.

  22. James Clerk Maxwell and the 60’s (the 1860’s) If a changing magnetic field makes an electric field (or current), wouldn’t a changing electric field make a magnetic field? Images acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://home.usit.net/~cmdaven/electro.htm and http://micro.magnet.fsu.edu/primer/java/electromagnetic/ through www.google.com.

  23. James Clerk Maxwell and the 60’s (the 1860’s) If a changing magnetic field makes an electric field (or current), wouldn’t a changing electric field make a magnetic field? Images acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://home.usit.net/~cmdaven/electro.htm and http://micro.magnet.fsu.edu/primer/java/electromagnetic/ through www.google.com.

  24. James Clerk Maxwell and the 60’s (the 1860’s) • This velocity is so nearly that of light, that it seems we have strong reason to conclude that light itself (including radiant heat, and other radiations if any) is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws. Images and quotes acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://en.wikipedia.org/wiki/Maxwell's_equations

  25. James Clerk Maxwell and the 60’s (the 1860’s) • This velocity is so nearly that of light, that it seems we have strong reason to conclude that light itself (including radiant heat, and other radiations if any) is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws. Images and quotes acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://en.wikipedia.org/wiki/Maxwell's_equations

  26. James Clerk Maxwell and the 60’s (the 1860’s) • This velocity is so nearly that of light, that it seems we have strong reason to conclude that light itself (including radiant heat, and other radiations if any) is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws. So, light must be a wave! Images and quotes acquired at http://www-groups.dcs.st-and.ac.uk/~history/PictDisplay/Maxwell.html and http://en.wikipedia.org/wiki/Maxwell's_equations

  27. 1905--Albert Einstein and the Photoelectric Effect Images and acquired at http://sol.sci.uop.edu/~jfalward/particlesandwaves/particlesandwaves.html

  28. 1905--Albert Einstein and the Photoelectric Effect Images and acquired at http://sol.sci.uop.edu/~jfalward/particlesandwaves/particlesandwaves.html

  29. 1905--Albert Einstein and the Photoelectric Effect Then light is both!!! (wave and particle) Images and acquired at http://sol.sci.uop.edu/~jfalward/particlesandwaves/particlesandwaves.html

  30. 1905--Albert Einstein and the Photoelectric Effect 1921 Nobel Prize (not for Relativity!!!) Then light is both!!! (wave and particle) Images and acquired at http://sol.sci.uop.edu/~jfalward/particlesandwaves/particlesandwaves.html and http://en.wikipedia.org/wiki/Albert_Einstein through www.google.com.

  31. In summary… • Light: • Acts like a particle • Acts like a wave • Refracts • Reflects • Diffracts • Interferes with itself • Has lots of different wavelengths (some visible) Image acquired at http://www.mic-d.com/curriculum/lightandcolor/reflection.html through www.google.com.

  32. Light Demonstrations Assignment Your Assignment… In your groups, prepare and perform a physics demonstration that shows the class one or more of these properties of light. Each person will write a description of the demo that contains the following: 1) A sketch of the setup with all parts labeled. 2) A list of materials required. 3) A list of steps to follow to perform the demonstration. 4) Explain which principle this demonstrates and how it demonstrates it. • Properties of light: • Acts like a particle • Acts like a wave • Refracts • Reflects • Diffracts • Interferes with itself • Has lots of different wavelengths (some visible) • Is polarized How cool your demo is will definitely be a factor in your grade on this assignment. 

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