Group+4

=17.4 - Sounds and Hearing=



Properties of Sound Waves

 * Intensity- The rate at which a waves energy flows through a given area. Intensity is measured by decibels (dB). Sound intensity depends on both the waves amplitude and the distance from the sound source.
 * Speed- In dry air of 20 degrees Celsius the speed of sound is 342m/s, that's more than 10x faster than your car on a highway. Sounds travel fastest in solids, then liquids, and finally gases. How dense, elastic, or how close the particle/molecule are together all effect the speed of sound.
 * Frequency and Pitch- Pitch is the frequency of sound as you perceive it. Pitch depends upon a waves frequency. High pitches have high frequency, while low pitches have low frequency.

Uses
Hearing with Ears Doppler Effect Video
 * Hearing With Ears- The outer ear gathers and focuses sound into the middle ear, which receives and amplifies the vibrations. The inner ear uses nerve endings to sense vibrations and sends signals to the brain.
 * Ultrasound is used in sonar and ultrasound imaging. Ultrasound uses sound to bounce around objects to create images.
 * Doppler Effect- The farther away the sound is the quieter and the closer it is the louder.