<p align="right">Last Update: <font color="#4f81bd">January 2, 2025</font></p> ## BIG IDEAS - The study of sound is known as acoustics. - Sound is a wave propagating through the air at a speed of ~770 miles per hour (~1240 km/h or ~344 m/s). - Sound is a longitudinal wave. - Particles vibrate to and from. ### Model - A wave on a slinky is a model of sound waves if one end of the slinky is oscillated back and forth and a series of longitudinal waves are produced. - A speaker produces sound by oscillating a diaphragm back and forth. ### Properties - Sound is a longitudinal wave. - Particles vibrate to and from. (See [[Module 1-1 Sound Production]]) - There are ==regions of compression (high pressure) and rarefaction (low pressure)==. - Sound can be characterized by velocity, frequency, wavelength, and amplitude. - Sound travels at approximately 344 m/s in air. (See [[Module 2 Speed of Sound]]) - Sound also has the properties of reflection, refraction, and interference. - Reflected sound waves are called echoes. [www.academo.org](http://www.academo.org) has a virtual oscilloscope. ### Relate Intensity Decibel levels, and Loudness - Loudness of sound depends on the amplitude of a sound wave. - The larger the amplitude, the more energy the wave has and the louder the sound. - Loudness is measured in decibels (dB). - Any sound above 80 dB becomes noise to the human ear. ### Slide Deck <div style="position: relative; width: 100%; height: 0; padding-top: 56.2500%; padding-bottom: 0; box-shadow: 0 2px 8px 0 rgba(63,69,81,0.16); margin-top: 1.6em; margin-bottom: 0.9em; overflow: hidden; border-radius: 8px; will-change: transform;"> <iframe loading="lazy" style="position: absolute; width: 100%; height: 100%; top: 0; left: 0; border: none; padding: 0;margin: 0;" src="https://www.canva.com/design/DAGSw39o0gg/M6hL-TOy8vYjDTJBAN5Jfw/view?embed" allowfullscreen="allowfullscreen" allow="fullscreen"> </iframe> </div> ### Video <iframe width="100%" height="480" style="border:0;" scrolling="no" src="https://go.screenpal.com/player/c06wDvVEK3I?width=100%&height=480&ff=1&title=0" allowfullscreen="true"></iframe> ### Related Topics --- [[Home|Home]] | [[Oscillations]] | [[Waves]] | [[Module 0 Sound]] | [[Module 1 Sound Waves]] | [[Module 1-1 Sound Production]] | [[Module 2 Speed of Sound]] | [[Module 3 Sound Intensity]] | [[Module 4 Doppler Effect]] | [[Electromagnetic radiation]]