Sound Waves Flashcards
All 6 cards in this deck
What are the steps by which a vibrating object produces a sound wave in air?
e.g. a struck tuning fork- The prongs vibrate and make nearby air particles vibrate.
- The air particles vibrate parallel to the direction the wave travels (longitudinal).
- This creates compressions and rarefactions that travel out through the air, transferring energy.
In which direction do air particles vibrate in a sound wave?
Parallel to the direction the wave travels — sound is a longitudinal wave.
In a sound wave travelling through air, what is a compression and what is a rarefaction?
A compression is a region where the particles are pushed closer together (higher pressure); a rarefaction is a region where they are spread further apart (lower pressure).
What happens when a sound wave in air reaches a solid surface?
e.g. an ear drum or a microphone diaphragmThe compressions and rarefactions push on the surface, making it vibrate at the same frequency as the sound wave. (A solid vibrating in air does the reverse and produces a sound wave.)
Why do processes that convert between sound waves and vibrations in solids only work over a limited frequency range?
A solid part only vibrates well at frequencies close to its own natural range, which depends on its size, stiffness and mass.
What are the steps by which the human ear detects a sound?
e.g. hearing a 500 Hz note- The sound wave makes the ear drum vibrate at the frequency of the sound.
- Small bones amplify the vibration and pass it to the cochlea.
- The cochlea converts the vibrations into electrical nerve signals sent to the brain.