Physics - Sound Flashcards
propagation
transmission of sound through a medium
Waves transfer
Energy without transferring matter
Waves transfer through
Solids, gasses, liquids, vacuums (empty spaces)
Frequency
Total waves that pass through a fixed point usually in one second
Period
The time taken for a wave to complete a cycle
Crest
Point where maximum displacement occurs
Trough
Point where minimum displacement occurs
Compression
Point in which particles are closest to each other
Rarefraction
Point in which particles are furthest from each other
How is sound produced
When matter vibrates
Speed of sound varies depending on?
the medium it travels through
Why does sound travel through solids fastest
because the particles are the densest and oscillate the most
Why does sound travel through warmer air faster
because the particles have more kinetic energy and bump into each other more
Why does sound travel through warmer air faster
Why does sound disappear
Inverse Square Law
Absorption
Reflection
Scattering and difraction
What is the inverse square law
sound energy gets spread over a larger area as it propagates, resulting in a decrease in its volume.
Why do some materials absorb sound better than others
some are able to dissipate and convert the energy into heat energy rather than reflect it
What causes echoes
When sound bounces off an extremely dense and reflective material back toward the source because it doesn’t have the space to hold the energy
What is the common feature needed for material to absorb sound?
Porosity, to trap the sound
How does sonar work
Records how long echo takes to return to its origin
How fast does sound travel in water
1500 m/s
Ultrasound
Term for sounds above our normal hearing range
How does ultrasound work
Sound waves pass through soft tissue but reflect off organs and the foetus
Relationship between frequency and period
p=1/f
to measure the length of a wave
every 2 intercepts
