Waves Flashcards
purpose of waves
to transport energy
longitudinal waves
particles of medium vibrate/ oscillate in the same direction as the energy travels
transverse waves
particles of medium vibrate/ oscillate at right angles to the direction of travel of the wave
amplitude
the maximum extent of a vibration or oscillation
crest
a point on wave with the maximum value/ highest point of upward displacement within a cycle
trough
a lowest point on wave with the minimum value of downward displacement within a cycle
transverse wave wavelength
minimum distance in which a wave repeats itself
frequency
number of waves that pass a point every sec (hertz)
period
time for one complete wave
the wave equation
wave speed = frequency x wavelength
frequency=1/time period
conclusion for slinky experiment:
the longer the slinky is stretched…
the faster the wave speed of a pulse travels along the slinky
conclusion for pendulum experiment:
the long the length of the pendulum…
the greater the time period, but the rate decreases slowly
what are sound waves?
vibrating air molecules
how many hertz can the human ear typically hear?
from 20hz-20000hz
what are sounds 20000+ hz called?
ultrasonic
for longitudinal waves, what does a high pitch result in the shape of the wave?
high frequency (distance between waves closer)
for longitudinal waves, what does a loud sound result in the shape of the wave?
large amplitude (height of the wave larger)
speed of sound in air
340m/s
things that have transverse waves
radio, infra red, water, skipping rope, guitar string
things that have longitudinal waves
sound
what surface reflect sounds better and what absorb sounds better? which one makes noise sound clearer?
polished surfaces; soft object surfaces; soft object surfaces
what is ultrasound?
sound waves of frequencies greater than 20000hz, above the upper limit of the hearing range for humans
how are ultrasounds made?
made by electronic systems which produce electrical oscillations which are used to generate the ultrasonic waves
uses of ultrasonic waves
- pre-natal scanning
- echo-sounding
- cleaning delicate objects
- detecting flaws and cracks
- echo-location by bats