Waves Vocabulary

trough

low point of a wave

crest

high point of a wave

frequency

the number of oscillations that occur in a given time period

amplitude

the maximum displacement of particles (positive or negative) during wave motion

hertz

the unit for the frequency of a wave; the number of waves per second

period

the time required for one wavelength to pass

stiffness

the degree to which a medium resists being compressed

circular waves

a wave in which wave energy causes both transverse and longitudinal motion, causing an overall circular pattern of movement

compression

a space in which particles have been pushed together

longitudinal wave

wave in which the oscillations are in the same direction as the wave motion; sometimes called a compression wave

periodic energy

an oscillating source of energy that repeats itself in a regular way

pulse

non-recurrent wave

rarefaction

a space in which the particles have been spread apart

transverse wave

wave in which the oscillations are at right angles to the direction of wave movement

disturbance

the displacement of an object from its equilibrium position by the input of energy

electromagnetic waves

waves in which electric and magnetic fields oscillate

equilibrium

the natural or rest position of a particle

mechanical waves

waves in which the particles of a medium oscillate

medium

any substance with a defined set of physical properties that can transmit energy

oscillate

to bob back in forth in regular way about a resting position

propagate

to transmit from one place to another in succession

wave

a disturbance that propagates through an area and transmits energy from one place to another

angle of incidence

the angel between the normal and the incident ray

angle of reflection

the angle between the normal and the reflected wave

angle of refraction

the angle between the normal and the refracted wave

boundary

the border where two different media come into contact

constructive interference

the addition of the crests of two different waves

destructive interference

the addition of a crest and a trough of two different waves

diffraction

a phenomenon displayed by a wave when it bends around an obstacle or passes through and opening and spreads out

interference

the addition of the disturbances caused by two or more waves

normal

a line that is perpendicular to the boundary and drawn at a point where the incident ray intersects the boundary

principle of superposition

a rule that disturbances caused by two waves at the same location are equal to the sum of the disturbances caused by each wave alone

ray

an arrow that is perpendicular to the wave fronts and indicates the direction of the wave motion

reflection

the change in the direction of the wave as it bounces of the boundary of two media

refraction

the change in the direction of a wave as it enters a new medium

transversal waves have

dips and peaks

longitudinal waves have

compressions and rarefactions

in earthquakes, longitudinal waves are

primary waves

in earthquakes, transversal waves are

secondary waves

in earthquakes, circular waves are

surface waves

longitudinal waves can travel through

any medium, preferably dense

transversal waves can travel through

solids only

circular waves can travel through

all media effectively

wavelength

distance from one point on one wave to a similar point on another wave