Properties of WavesProperties of Waves

Amplitude, Wavelength, Amplitude, Wavelength, Frequency, SpeedFrequency, Speed

Slide 1Slide 1Main IdeaMain Idea How to draw How to draw

wave wave diagramsdiagrams

DetailsDetails Draw a transverse Draw a transverse

wave like a wavy wave like a wavy roperope

Draw a longitudinal Draw a longitudinal wave like spring wave like spring (slinky) stretching (slinky) stretching and compressingand compressing

Slide 2Slide 2Main IdeaMain Idea What is What is

amplitudeamplitude

DetailsDetails Amplitude is the Amplitude is the

maximum distance of the maximum distance of the medium particles from medium particles from REST to CRESTREST to CREST

Draw a straight line Draw a straight line down the middle of the down the middle of the wave, half-way between wave, half-way between Crest and Trough. This Crest and Trough. This is the Rest positionis the Rest position

More amplitude takes More amplitude takes more energymore energy

Slide 4Slide 4Main IdeaMain Idea What is What is

amplitude of amplitude of transverse transverse waves?waves?

DetailsDetails Distance from REST Distance from REST

to CREST –or- REST to to CREST –or- REST to TROUGHTROUGH

Slide 4Slide 4Main IdeaMain Idea What is What is

amplitude of amplitude of Longitudinal Longitudinal waves?waves?

DetailsDetails Amplitude is how Amplitude is how

compressed or compressed or rarefied the medium rarefied the medium is.is.

One compression to One compression to another is like one another is like one crest on a transverse crest on a transverse wavewave

Slide 4Slide 4Main IdeaMain Idea What is What is

wavelengthwavelength

DetailsDetails Distance between Distance between

two corresponding two corresponding parts of a waveparts of a wave

Transverse – Crest to Transverse – Crest to Crest –or- Trough to Crest –or- Trough to TroughTrough

Longitudinal- Longitudinal- Compression to Compression to CompressionCompression

Slide 4Slide 4Main IdeaMain Idea What is What is

frequency?frequency?

DetailsDetails Frequency is number Frequency is number

of waves that pass a of waves that pass a point in one secondpoint in one second

Measured in HERTZ Measured in HERTZ (one hertz=one wave (one hertz=one wave per second)per second)

Slide 4Slide 4Main IdeaMain Idea What is What is

speed?speed?

DetailsDetails Speed is how far a Speed is how far a

wave travels in one wave travels in one unit of time unit of time (distance/time)(distance/time)

Speed = wavelength x Speed = wavelength x frequencyfrequency

Frequency=speed/Frequency=speed/wavelengthwavelength

Wavelength=speed/Wavelength=speed/frequencyfrequency

How fast do waves move?

Period

The time it takes for 1 wave to pass by,

measured in seconds

Frequency

The number of waves that pass by in 1

second

Frequency is measured in Hertz

Hz = 1 Second

                             

Frequency = 1

Period

Example: A wave passes by every 2 seconds

Period = 2 s

Frequency = ½ = 0.5 Hz

Wave Speed

The speed at which a wave passes

through a medium

Wave speed =

Frequency x wavelength

(Hz) (m)

Unit for speed is m/s

Example 1

How fast is a wave moving that has a

frequency of 5 Hz and a wavelength of 0.5 m?

Speed = Frequency x Wavelength

Speed = 5 Hz x 0.5 m

Speed = 2.5 m/s

Example 2

A wave passes by every 3 seconds and the distance between each crest of the wave is 5 meters. What is

the speed of the wave?

Period = 3 seconds

Frequency = 1/3 = 0.33 Hz

Wavelength = 5 m

Speed = 0.33 Hz x 5 m

Speed = 1.65 m/s

Example 3

A mosquito makes a sound by beating its wings 600

times every second. If the sound waves move at 340

m/s, what is the wavelength of the sound waves?

Speed =freq.x wavelength340 m/s = 600 x wavelength

Wavelength = 0.57 m