1. Please be Seated

2. Making Waves Physics is Phun January 2007

3. View this PowerPoint program Programs for Pre-College Students

4. Bell in Vacuum Experiment

5. Transverse Waves

6. c = f c = speed of light f = frequency  = wavelength

7. Speed of Light (in a vacuum) c = 300,000,000 m/s = 3 x 10 8 m/s

9. Longitudinal Waves

10. s = f s = speed of sound f = frequency  = wavelength

11. Speed of Sound s = 331.45 m/s ~1087 ft/s at 0 o C s = depends on temperature but not on pressure

12. The “Sonic” Spectrum Infrasound: 20 kHz (~10 13 Hz maximum)

13. Light waves: 1. are transverse waves. 2. do not require a medium. Sound waves: 1. are longitudinal waves. 2. require a medium.

14. Wave Properties I Superposition Hugygens’ Principle Doppler Effect

15. Superposition

16. Huygens’ Principle

17. Doppler Effect Sound Doppler Ball Moving Cars, etc. Light Spectra of stars

18. Fraunhofer Spectrum

19. Wave Properties II Diffraction Interference Reflection Refraction

20. Diffraction Waves spread out and bend around corners within the same medium.

21. Highway Sound Barrier Photograph courtesy of Enterprise Flasher Company

22. Interference Two-source interference pattern Moire figure model

23. Bose QuietComfort 2 Noise Cancelling Headphones

24. Light examples

25. “Iridescence” of peacock feather

26. Reflection

27. Refraction Waves bend due to variation of medium.

28. Waves at the Beach

29. Mirage Formation

30. Water Mirage

31. Desert Lake

32. Mirage Compliments of Robert Greenler

33. Sunrise over the Ocean

34. The End See you next time! Animated Gifs compliments of bellsnwhistles.com We are on the web at http://www.physics.umd.edu/lecdem/