PHY 2020 Chapter Notes - Chapter 20: Rarefaction, Sound, Sound Energy
Document Summary
Most sounds are waves produced by the vibrations of matter. In each of these cases, the original vibration stimulates the vibration of something larger or more massive. This vibrating material then sends a disturbance through the surrounding medium; usually air, in the form of longitudinal waves. We describe our subjective impression about the frequency of sound with the word pitch. Sound waves with frequencies below 20 hertz are infrasonic, and those with frequencies above 20,000 hertz are called ultrasonic. Checkpoint 1: what is the wave frequency of sound produced by a 220-hertz turning fork: 220 hz. Most sound that we hear are transmitted through the air: however, any elastic substance- whether solid, liquid, gas, or plasma- can transmit sound. Elasticity is the property of a material that has changed shape in response to an applied force and then resumes its initial shape once the distorting force is removed. Relative to solids and liquids, air is a poor conductor of sound.
