Waves and Sounds Ch. 18

Frequency and Pitch  A pitch is the highness or lowness of a sound.  The pitch you hear depends on the frequency of the sound waves.

Frequency and Pitch  The higher the frequency, the higher the pitch.  Healthy Human Ear can hear from 200 Hz to 20,000 Hz.

Frequency and Pitch  2 kinds of waves we can’t hear:  Ultrasonic waves – frequency above 20,000 Hz Used in sonar as well as in medical diagnosis and treatmentUsed in sonar as well as in medical diagnosis and treatment

Frequency and Pitch  Infrasonic waves – frequency below 20 Hz Produced by heavy machinery or thunder…you can feel it rumble in your body but not actually hear itProduced by heavy machinery or thunder…you can feel it rumble in your body but not actually hear it

Intensity and Loudness  Intensity of a sound wave depends on the amount of energy in each wave. This corresponds to a wave’s amplitude.This corresponds to a wave’s amplitude. As intensity of a sound wave increases, the amplitude increases.As intensity of a sound wave increases, the amplitude increases.

Intensity and Loudness  Loudness is the human perception of sound intensity. Measured in decibels (dB).Measured in decibels (dB).

Doppler Effect  An increase or decrease in wave frequency, caused by motion of the source and/or motion of the observer.

Doppler Effect Not Moving Moving Higher f Smaller Higher pitch Lower f Higher Lower pitch

Doppler Effect

What is music?  Noise has no set pattern and no definite pitch.  Music has a regular pattern, created using specific pitches and sound quality.