Please be Seated

1. PleasebeSeated

2. Physics is PhunNovember 2005 Einstein and the 2005 Year of Physics

3. In 1905, at the age of 25,Einstein published papers on Brownian Motion, the Photoelectric Effect, and Relativity.

4. This achievementhas been called the most productive yearfor any scientist,ever.

5. The centennialof this eventis celebrated as the2005 Year of Physics

6. Quote of the Century:"The word ‘genius’ isn'tapplicable in football. A geniusis a guy like Norman Einstein."--Joe Theismann, NFL footballquarterback & sports analyst.

7. In the matter of physics, the first lessons should contain nothing but what is experimental and interesting to see. A pretty experiment is in itself often more valuable than twenty formulae extracted from our minds. -Albert Einstein

8. Some Reference materials:National Science Foundation web siteAmerican Association of Physics Teachers web siteUniversity of Maryland Physics Question of the Week web site

9. Topics for this evening: • Brownian Motion • The Photoelectric Effect • Relativity

10. Brownian motion: is the small molecular motion inherent in all molecules, even at the lowest possible temperature.

11. Discovered by botanistRobert Browne (1773-1858)“..in 1827. The story goes that Brown was studying pollen particles floating in water under the microscope.” From Wikipedia, the free encyclopedia.

12. Brownian Motionof smoke particlesdemonstration

13. Java appletofBrownian motion

14. Mechanical ModelofBrownian Motion

15. “More accurate” description: statistical fluctuations requiring ~10,000 net molecular collisions to change particle motion.

16. Implications ofBrownian Motion: • Air pressure • Diffusion of gases

17. Reducing Brownian Motion Minimizing molecular motion in atomic clocks increases accuracy of clocks and GPS.

18. William Phillips Professor of Physics, University of Maryland Nobel prize in 1997 for Laser cooling of atoms Video showing magnetically trapped block of cesium atoms

19. The Photoelectric Effect: describes the particle behavior of light.

20. Einstein received the 1921 Nobel Prize in Physicsfor work on thePhotoelectric Effect

21. Ef = h fE = photon energyh = Planck’s constant (~6.6x10-34 Joule-sec)f = light frequency

23. KEe = Ef – W = hf - W A single photon of light is absorbed by an electron, causing it to be ejected from the surface of the metal. Graphic from Wikipedia, the free encyclopedia.

24. Demonstrations • Photoelectric effect • in zinc • 2. Full photoelectric effect

25. Applications: Solar power Solar engines Solar switches “Hydrogen” economy

26. 2005 Nobel prizein Physics toGlauber, Hall, & Haensch(application of quantum nature of light to build atomic clocks to 10-15 accuracy and thus improve GPS accuracy )

27. Relativity: deals in part with frames of reference and how we view physical phenomena.

28. When might a physics experiment be correct? Physics experiments are fully accurate only in an inertial frame of reference or in a local inertial frame.

29. Galilean Relativityand theFunnel Cart Demonstration

30. Local inertialframe of referencedemonstration

31. Einstein’sfavorite demonstration

32. The Speed of Lightand the search for aPreferred Inertial Frame of Reference

33. TheMichelson-Morleyexperiment

34. 1. There is NO preferred frame of reference.

35. 2. Thespeed of Lightis the same in allinertial frames

36. Applicationsof Relativity

37. Michelson Interferometerwith White Light Color Mixing:W = R + G + BW – R = G + B = CW – G = R + B = MW – B = R + G = Y

38. Michelson Interferometer setup using White Light

39. Michelson InterferometerwithWhite Light

40. Michelson InterferometerwithWhite Light Full motion of mirror for this video ~10 μ = 0.000,010m = 0.01 mm

41. The EndSee you in January! We are on the web at http://www.physics.umd.edu/lecdem/ Animated Gifs compliments of bellsnwhistles.com