10.3 Hearing + 10.7 Brain Flashcards
What is sound produced by
Vibrations of objects
Whats frequency
Unit
Vibrations made per second
Hertz
Relationship between tuning fork length and frequency
Shorter prong higher frequency
越短越快越高音
how is sound transmitted
- Object vibrates
- Push on surrounding air particles
- Particles vibrate, travel through air
Sound must travel through a ____, it can be a _____, ______, _____
Medium
Solid liquid gas
Sound is transmitted through __________ in these medias
Vibrations of particles
Why can’t sound travel through vacuum
No air, no particles transmit sound, no sound can be heard
Speed of sound in diff media
Fastest in solids
Slowest in gases
Why cant sound be heard in space
Space is a vacuum, sound cant travel through it
Ear structure
Pinna, ear canal, ear drum, ear bones, cochlea, auditory nerve
How we hear
- Pinna collects sound, directs into ear canal
- Travels down ear canal to middle ear
- sound causes eardrum vibrate, vibrations transmitted to ear bones
- 3 ear bones amplify eardrum’s vibrations, transmit to inner ear
- Sensory hair cells in cochlea detect vibrations, produce signals
- Signals fr sensory hair cells sent to brain through auditory nerve , interprets signals as sounds
Why cant hear clearly
What helps them hear better
Ear bones / sensory hair cells in cochlea not function properly
hearing aid / cochlea implant
Limitation
Audible frequency range; only hear within certain range of frequency, 20-20000 Hz
Whats noise, sources, cause
Unwanted, disturbing
Traffic, construction work, Humm a voices, loud music
Noise pollution
Measure sound level
Unit
Decimal meter
dB