speed of waves
- speed of sound is universal
- doesn’t depend on wavelength, frequency, or amplitude
- otherwise, couldn’t understand speach or music
- about 300 m/s or 1000 ft/s or 700 mph
- determined by the speed of air molecules
- higher at higher temperatures
- can use it to determine how far away lightning is
- measure time between flash and thunder, multiply by speed of sound
- speed of light is universal and fast
- about 1 million times the speed of sound
- nothing can exceed light speed (as far as we know)
- wave nature of visible light is not immediately obvious
- very short wavelengths, 10-6 m
- very high frequencies, f = speed/??= 300 x 1012 cycle/s