9.4 Flashcards
(15 cards)
What type of wave is sound?
Compression wave
Sound is transmitted as a compression wave that requires a medium with particles to travel.
Why can’t sound be transmitted in a vacuum?
There are no particles to push closer together or spread out
Sound requires a medium to propagate, which is absent in a vacuum.
What material does sound travel best in?
Through elastic materials, like metals
Elastic materials allow sound to travel with minimal energy loss.
What causes sound?
Vibrations
Vibrations create compressions and rarefactions in the medium.
What is created when a vibrating ruler moves up?
Compression
Air particles above the ruler are pushed together, creating compressions.
What is created when a vibrating ruler moves down?
Rarefaction
Air particles below the ruler are spread out, leading to rarefactions.
How does the speed of sound change with temperature?
Increases at higher temperatures
The speed of sound is greater in warmer air.
What is an echo?
Reflection of a sound wave
It allows estimation of distance to large objects by timing the return of the sound.
What is echolocation?
Using echoes to locate objects
Animals like bats and dolphins use echolocation to navigate and hunt.
What technology uses echoes for mapping the ocean floor?
SONAR
SONAR stands for Sound Navigation And Ranging.
What is ultrasound?
High-frequency sound used in medicine and industry
Ultrasound is beyond the range of human hearing.
What are the ossicles?
Three small bones in the middle ear
The ossicles are the hammer, anvil, and stirrup.
What is the cochlea?
Spiral-shaped system of tubes in the inner ear
It contains fluid that moves hair cells in response to sound vibrations.
What is the range of frequencies that humans can hear?
20 Hz to 20,000 Hz
This range can vary with age and hearing ability.
What is the unit of measurement for loudness?
Decibel (dB)
Sound intensity is measured in decibels, indicating loudness levels.
