1. Chapter 12 Section 2

2. Amplitude Amplitude of a sound wave indicates the amount of energy in the wave Longitudinal wave’s amplitude is the tightness of compression (pressure) Also measured by separation of rarefaction Intensity of sound is amount of energy that moves through an area If intensity is great, energy is great, and wave travels farther Loudness is human perception of intensity

3. Loudness Humans perceive loudness changes when intensity is multiplied by 10 10 times more intensity is perceived as twice as loud Scale to measure loudness is the decibel scale Faintest sound average person can hear is 0 dB Sounds with loudness above 120 dB can harm hearing YouTube - Science of Sound

4. Pitch Pitch is human perception of frequency Remember, frequency is: Number of waves that pass in one second Measured in Hertz (Hz) Average human can hear from 20 Hz to 20 000 Hz Frequencies greater than 20 000 Hz are called ultrasonic Frequencies less than 20 Hz are called infrasonic

5. Doppler Effect Waves appear to be squeezed (increase frequency) or expanded (decrease frequency) when source or detector moves YouTube - Really Cool Doppler effect video YouTube - The Doppler Effect YouTube - Fire Engine siren demonstrates the Doppler Effect YouTube - Fire Engine siren demonstrates the Doppler Effect Doppler effect is used in Doppler radar to tell movement of clouds Also used in speed gun to detect speed of cars