1. Sound

2. Speed Factors State of matter  Fastest in a solid; slowest in a gas. Density  Faster in denser substances (iron versus copper). Elasticity  Faster in elastic substances (aluminum versus rubber). Temperature  Travels slowest in coldest temperatures.

3. Intensity of Sound Intensity  Amount of energy or amplitude of a sound wave. Loudness  human perception of intensity. Decibel Scale  measures loudness (threshold of pain = 120 dB).

4. Pitch of Sound Pitch  Frequency of the wave; more frequency = higher pitch. Human Range  20 Hz to 20,000 Hz. Ultrasonic = above 20,000 Hz. Infrasonic = below 20 Hz.

5. Doppler Effect Wavelengths get pressed together between two objects moving closer to each other, so you get a higher pitch.

6. Uses of Sound Acoustics  study of sound. Echolocation  using sound to locate objects. SONAR  Underwater sound waves to locate objects (fish, sunken boats). Ultrasound Machine  Ultrasonic sound waves are used to produce an image of the interior of our bodies.

8. Music – sound in a regular pattern Resonance  vibrates at its natural frequency. Instruments  have ways to alter the “natural frequency” of the instrument. Beats  Heard when two or more waves with different frequencies are played at the same time.