<p align="right">Last Update: <font color="#4f81bd">January 2, 2025</font></p> ## BIG IDEA When a body moves through air it compresses the air in front of it. This air then expands, compressing the next layer of air and passing the disturbance from one layer of air to the next. If the body oscillates then a continuous wave is propagated through the air. This is called a sound wave. A sound wave is a ==propagation== of changing pressure. This causes layers of gas to oscillate but remember, the individual molecules of the gas are moving with random motion. Since the disturbance is in the same direction as the transfer of energy, sound is a longitudinal wave. ### EXAMPLE [](https://lh6.googleusercontent.com/6ZQ55kZoXCJGMBPJreQwv45XFi2RkFT_D7CDefbBnI4hv3v2sg0AN92hrKp-GyTDZwXjpoT7dKn340Jwvf6y6Un2KCRwle-sYhy_OcLtU29JWVic7ZZ4XAzg8M2_PAw2Bt1UOEJI) A tuning fork is a great way to describe the production of sound waves. Striking a tuning fork on a table stop leads to oscillations of air. ### Related Topics --- [[Home|Home]] | [[Oscillations]] | [[Waves]] | [[Module 0 Sound]] | [[Module 1 Sound Waves]] | [[Module 2 Speed of Sound]] | [[Module 3 Sound Intensity]] | [[Module 4 Doppler Effect]] | [[Electromagnetic radiation]]