Waves Flashcards
what 2 types of waves are there?
transverse
longitudinal
define transverse waves
oscillating perpendicular to the direction of energy transfer
define longitudinal waves
oscillating parallel to the direction of energy transfer
give an example of a transverse wave that isn’t a seismic wave
ripples on a water surface
what do longitudinal waves on a diagram show?
area of compression and rarefaction
how do you identify where there are areas of compression on a longitudinal waves diagram?
where the lines are closer to each other
how do you identify where there are areas of rarefaction on a longitudinal waves diagram?
where the lines are further apart
define amplitude
maximum displacement of a point on a wave away from its equilibrium
define wavelength
the distance from a point on one wave to the equivalent point on an adjacent wave
define frequency
the number of waves passing a point in each second
what is the formula to find period?
period = 1 / T
define wave speed
the speed at which energy is transferred through the medium
what is the formula to find wave speed?
Wave speed = frequency x wavelength
Describe a method to measure the speed of sound in the air
Measure distance travelled by wave using a meter ruler
Measure the time taken for the wave to travel the measured distance with a timer/stopwatch
Divide the distance by the time
what are the 3 things that can happen to a wave when it meets a boundary between 2 different materials?
reflection
refraction
absorption
What restricts the limits of human hearing?
Within the ear, sound waves cause the ear drum and other parts to vibrate which causes the sensation of sound. The conversion of sound waves to vibrations of solid works over a limited frequency range
Describe processes which covert wave disturbances between sound waves and vibrations in solids
The human ear detects sound. Sound waves enter the ear canal and cause the eardrum to vibrate. Three small bones transmit these vibrations to the cochlea. This produces electrical signals which pass through the auditory nerve to the brain, where they are interpreted as sound.
What is the effects of sound waves on the ear drum?
Causes ear drum to vibrate
why do such process only work over a limited frequency range from and the relevance of this to human hearing:
Human hearing is limited by the size and shape of your ear drum, as well as the structure of all the parts within the ear that vibrate to transfer the energy from the sound waves
How are waves used for detection and exploration?
When a wave meets a boundary between two materials, it can be reflected or partially reflected.
The wave may continue travelling in the same direction, but at a different speed, or it could be absorbed or refracted
This can be used to study the paths of waves through structures and can give hints to some of the properties.
define ultrasound
a sound wave that is above the human range of hearing, 20kHz.
How are ultrasounds created?
- An ultrasound wave is transmitted and it will pass through the material
- The wave will meet a change in material density
- The wave will be partially reflected
- The detector records the time from transmission to detection and uses it to create an image based on distance