Physics - Waves

Front 1

amplitude

Back 1

the maximum distance a wave moves from its central position

Front 2

compression

Back 2

points on a longitudinal wave where particles are closer together (higher pressure in a gas)

Front 3

crest

Back 3

highest point on a transverse wave

Front 4

frequency

Back 4

the number of wavelengths that pass a point in one second (measured in Hertz)

Front 5

Hertz

Back 5

the unit for measuring frequency (named after Heinrich Hertz)

Front 6

longitudinal

Back 6

a wave whose vibrations are back and forth in the same direction it is travelling

Front 7

mechanical wave

Back 7

vibrations passing through a solid, liquid, or gas

Front 8

medium

Back 8

a material (that mechanical waves travel through)

Front 9

period

Back 9

the time taken for one complete wave to pass a point

Front 10

pitch

Back 10

how high or low a musical note is due to its frequency, e.g. high frequency = high pitch

Front 11

propagation

Back 11

movement of the wave, the direction in which a wave travels

Front 12

pulse

Back 12

a small section of a wave (i.e. not a continuous wave)

Front 13

rarefaction

Back 13

points on a longitudinal wave where particles are further apart (lower pressure in a gas)

Front 14

reflected

Back 14

an outgoing wave that rebounds from something such as the end of a string

Front 15

source

Back 15

object that emits (gives off) waves

Front 16

transmission

Back 16

the action or process of transmitting something or the state of being transmitted

Front 17

transverse

Back 17

a wave whose vibrations are perpendicular (at right angles) to its direction of travel

Front 18

trough

Back 18

lowest point on a transverse wave

Front 19

wave velocity

Back 19

the velocity at which a point on the waves travels e.g. how fast the crest of a wave moves through water

Front 20

wavefront

Back 20

the diagram showing the shape of a wave at a given time

Front 21

wavelength

Back 21

the distance between successive crests of a wave, especially as it affects their ability to communicate with others

Front 22

superposition

Back 22

adding the displacement of one wave to another

Front 23

superimpose

Back 23

adding the displacement of one wave to another

Front 24

constructive

Back 24

when the displacement of two waves add to make a larger displacement

Front 25

destructive

Back 25

when the displacement of two waves add to make a smaller displacement (or cancel out to give no displacement)

Front 26

in phase

Back 26

when the points on two waves have the same motion. When two waves are exactly in phase (also known as 0 degrees phase difference) they add to give double the amplitude

Front 27

out of phase

Back 27

when the points on two waves have the opposite motion. When two waves are exactly out of phase (also known as 18 degrees phase difference) they add to give zero displacement

Front 28

standing wave

Back 28

a type of wave formed when two waves travelling opposite directions in a medium e.g. string or pipe add up in such a way that there are points of no vibration (nodes) and points of maximum vibration

Front 29

node

Back 29

the point on a standing wave where the medium is not vibrating

Front 30

antinode

Back 30

the point on a standing wave where the medium has maximum vibration

Front 31

resonant frequency

Back 31

the frequencies of vibration at which standing waves will be formed in a medium

Front 32

fundamental frequency

Back 32

the lowest frequency of vibration that will cause a standing wave to form in a medium i.e. the lowest resonant frequency

Front 33

harmonic

Back 33

the frequencies of vibration that will cause standing waves to be formed in a medium

Front 34

overtone

Back 34

the frequencies of vibration that are higher than the fundamental frequency and will cause a standing wave to be formed in a medium

Front 35

timbre

Back 35

the characteristic sound that different musical instruments give to the same notes. Due to different waveforms but the same frequency, also seen on the frequency graph where they have the same fundamental frequency but different harmonic frequencies at different levels

Front 36

beats

Back 36

the regular pulsing of the loudness/quietness of a sound caused when two similar frequencies are played at the same time. The frequency of variation in loudness is called the beat frequency and is difference between the two frequencies being played

Front 37

incident

Back 37

an incoming wave that hits something such as end of a string

Front 38

reflection

Back 38

change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves.

Front 39

boundary

Back 39

the point between two different mediums

Front 40

diffraction

Back 40

a change in direction of waves when they bounce off a barrier

Front 41

refraction

Back 41

a change in the direction of waves as they pass from one medium to another