caused by vibrating objects, these
mechanical vibrations are passed through a
surrounding medium as a series of
compressions, they're a longitudinal
wave(vibrations along a straight line)
generally travel faster in solids
then liquids then gases
due to the particles been closest in
solids then liquids then gases
can't travel in space - its a vaccum
can reflect and refract
sound waves will be reflected
by hard, flat surfaces
very noticeable in empty
room: without furnishings it
echoes but with furniture etc
the sound waves are
absorbed quickly so they
can't echoe
echoes are reflected
sound waves and are
delayed from the
original sound as they
have to travel further
sound waves also refract(change direction)
as they enter different media(material)
when entering denser materials they speed
up as particles in denser media are closer
together(this speeding up is hard to spot in
normal circumstances as sound waves are
always spreading out so much.
higher frequency =
higher pitch + shorter
wavelength
frequency is number of complete vibrations
each second so frequency of 100Hz = 100
vibrations a second
frequency measured in Hz - kHz(1000 Hz) - MHz(1,000,000Hz)