PhysicsCode 5054
Sound
What this topic asks you to be able to do
- Outline how vibrating sources generate sound
- Describe the longitudinal character of sound waves, along with the compressions and rarefactions they contain
- Give the approximate band of frequencies humans can hear, from 20Hz to 20000Hz
- Explain why a vacuum cannot carry sound waves, and describe an experiment showing that this is so
- Outline how altering the amplitude and frequency of sound waves changes their loudness and pitch
- Outline how different sound sources give rise to sound waves of differing qualities (timbres), as revealed by the shapes of oscilloscope traces
- Describe an echo as a sound wave that has been reflected
- Outline simple experiments that demonstrate the reflection of sound waves
- Describe a method that uses measurements of distance and time to find the speed at which sound travels through air
- Know that sound travels through air at a speed of roughly 330–350 m/s.
- Know that, generally, sound moves more quickly through solids than liquids, and more quickly through liquids than gases.
- Define ultrasound: sound whose frequency lies above 20kHz.
- Describe how ultrasound is put to use in cleaning, prenatal and other medical scanning, and in sonar (including working out depth or distance using time and wave speed)