SPCH 103 Lecture Notes - Lecture 4: Sound Energy, Diffraction, Refraction
27 Apr 2020
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Compression= areas in which the air molecules are closer together, generating more pressure. Rarefactions= areas where the air particles are more distant from each other (less pressure density) Sound is a wave of pressure changes that propagates through the air. Periodic= wave that repeats in a regular pattern. Simple periodic wave= made of one frequency that repeats in time. Complex periodic waves= made of more than one frequency that repeat in time. Periodic sound made of one frequence= pure (simple) tone. Periodic sound made of more than one frequency= complex tone. Aperiodic waves= waves that do not repeat in a regular way. Transient aperiodic waves= (instantaneous or momentous)- they do not continue in time, like a clap or drum snare. Five possible boundary behaviors: reflection (bouncing off, diffraction (bending around, transmission (going through, refraction (change in velocity, absorption (wave transfers its energy to the material it penetrates. Some is transformed into heat and some is transmitted through)
