PSYC 100 Lecture Notes - Lecture 10: Basilar Membrane, Eardrum, Sound

• School: Queen's University
• Department: Psychology
• Course: PSYC 100
• Professor: Jordan Poppenk

Document Summary

This vibration causes adjacent air molecules to become compressed into local regions of increased pressure, and rarefied in local regions of de(cid:272)(cid:396)eased p(cid:396)essu(cid:396)e. these p(cid:396)essu(cid:396)e (cid:272)ha(cid:374)ges t(cid:396)a(cid:448)el th(cid:396)ough the ai(cid:396) to ou(cid:396) ea(cid:396)s i(cid:374) a (cid:449)a(cid:448)e. "". Light waves, as you learned last week, have wavelength and amplitude. The a(cid:373)plitude of a sou(cid:374)d (cid:449)a(cid:448)e dete(cid:396)(cid:373)i(cid:374)es the sou(cid:374)d"s intensity. Fo(cid:396) sou(cid:374)d, (cid:449)e t(cid:455)pi(cid:272)all(cid:455) do(cid:374)"t talk a(cid:271)out wavelength, but instead talk about a closely related characteristic, frequency (which can be directly calculated from the wavelength). Just as a source of illumination (like the sun or a light bulb) usually emits light of many different wavelengths simultaneously, most sounds consist of many different frequencies, which can be shown in a spectrum. Eight cycles or periods of the waveform are shown here (the waveform goes from a trough through zero then to a peak and back to a trough [one period] eight times). The wavelength is the distance the sound travels in one cycle.