Political Science 1020E Lecture Notes - Lecture 6: Eardrum, Intermolecular Force, Sound
2 Oct 2016
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If we focus on a single molecule of air, we see it moves back and forth like a sine or cosine graph. Displacement of that air molecule as it oscillates back and forth. Equilibrium position: undisturbed position of that air molecule, turn up volume. Oscillations become larger, sound becomes louder: amplitude=a. Maximum displacement of air molecule from equilibrium. Not the entire length, but only from the center line: period=t. Time it takes for air molecule to travel back and forth fully one time. Humans can hear 20 hz to 20,000 hz. Dogs up to 40,000 hz: wavelength (lambda) Distance vs. time graph would give us period. Distance vs. position graph would give us wavelength. Light and other electromagnetic waves have waves or particle-like characteristics. All or nothing-either we absorb all or none of the energy) Energyphoton= hf h= planck"s constant: 6. 26x10-34 joules*seconds f=frequency of wave, number of oscillations/second in hertz. Oscillation: rapid back and forth movement.
