16 Traveling waves (Overview)
Sources of sound vibrate. A short time later, the disturbance arrives at a detector and the detector vibrates in response to the disturbance. But what happens in between source and detector? What does sound look like as it travels?
Sound has a lot in common with ripples on a pond. Dip your finger in a pond and ripples travel outward from the the source. Dip your finger repeatedly, and a series of ripples travels outward from the source. Sound “ripples” are almost impossible to see directly, but there’s plenty of reason to believe they exist. A wave model for sound raises lots of questions about sound?
- What role does air play in sound?
- What, exactly, is moving when sound travels from place to place?
- How are the sound “ripples” made? What do they look like?
- How are loud sounds different from those quiet sounds?
- How are high pitch sounds different than low pitched ones?
Traveling Waves: Learning Objectives
- Distinguish between the motion of a wave and motion of the material in which the wave travels
- Distinguish between pulse and wave
- Describe the motion of a sound wave
- Describe the motion of the air particles in a sound wave
- Distinguish between longitudinal and transverse waves
- Define and describe wavelength, frequency and amplitude for L-waves and T-waves
- Explain the relationship among wave speed, frequency and wavelength
- Identify things that affect the speed of a wave (and things that don’t)
- Apply the equations and to solve numerical and non-numerical problems
- Describe Doppler effect and apply the Doppler effect equation: