Lab Notes: Week 6, Sound Waves, Physics 3LB at UCI

Wk6: Sound Waves
Sunday, February 9, 2020 9:58 PM




• Sound waves are pressure waves that travel through air.


• The speed of sound depends on temperature.


○ Speed of sound in air: 𝑣 = 331.4 + 0.6𝑇 𝑚/𝑠 (6.1)


○ The temperature is in degrees Celcius.


• To determine speed of sound, divide the wavelength by the period of the wave. (v = l/T)


○ l: is the distance moved by the second speaker.


○ T: is the period of the wave given by the scope.


• In the experiment: We will bounce sound waves from one speaker(1) off of another


speaker(2), and view how it will interfere w/ new sound waves(1).


• Standing Wave Pattern: superposition in multiple waves, giving rise to a stationary


pattern.


• When two waves meet, they are pushed in the air in different directions and combine into


a superposition.


• When sound waves hit a wall, much of their energy is reflected back in the other


direction.


• Constructive Interference: occurs when reflected and un-reflected waves add together


rather than cancel.


○ When constructive interference occurs, its sound intensity is greatly enhanced -->


This is RESONANCE!


○ When the speakers are separated by proper distance(l) for constructive


interference, a weak resonance occurs, and sound intensity is maximized!