![Page 1: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/1.jpg)
Waves
![Page 2: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/2.jpg)
What Are Waves?Wave – a disturbance that transfers energy
-- the energy transferred through a wave can be carried from the disturbance, through the wave, to another object
Ex: wind gives energy (a disturbance), creating waves on an ocean, and the ocean carries that energy to a boat, and the energy rocks the boat up and down
-- the energy from the disturbance is transferred through a medium
![Page 3: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/3.jpg)
MediumsMedium – the substance through which a wave travels
-- in an ocean wave, water is the medium
-- in sound waves, air is the medium
It is important to understand that the wave DOES NOT CARRY the medium itself. It only moves energy through the medium.
-- the ship doesn’t move on the waves, it only bobs up and down
![Page 4: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/4.jpg)
What Causes Waves?Waves are created when a source of energy causes a vibration in a medium
Vibration – a repeated back-and-forth or up-and-down motion
-- some mediums can vibrate a lot with only a little energy input
-- other mediums only vibrate a little with a lot of energy input
-- the amount of vibration depends on the spacing and type of molecules within the medium
![Page 5: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/5.jpg)
Types of WavesThere are three different types of waves, which are solely characterized by the way that they move.
The three types of waves are:
-- Transverse waves
-- Longitudinal Waves
-- Surface Waves
![Page 6: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/6.jpg)
Transverse WavesTransverse waves – waves whose mediums move a right angles (perpindicular) to the direction of overall wave travel
-- if the wave below moves left-to-right, the medium will move up-and-down
-- like whipping a rope
Parts of a Transverse Wave
Crest – the “high” parts of the transverse wave
Trough – the “low” parts of the transverse wave
![Page 7: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/7.jpg)
Longitudinal WavesLongitudinal Waves – waves whose mediums move in the same direction as overall wave travel
-- like squeezing and releasing a slinky spring
-- longitudinal waves are often called compressional waves
Parts of a Longitudinal wave
Compressions – areas where the molecules in the medium are tightly squeezed together
Rarefactions – areas where the molecules in the medium are spread apart
![Page 8: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/8.jpg)
Surface WavesSurface Waves – waves that form at the boundary between two different mediums
-- the bouncing of waves vibrating differently create circular-shaped waves
![Page 9: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/9.jpg)
Wave PropertiesDespite the different types of waves, all waves share the same basic properties:
-- amplitude
-- wavelength
-- frequency
-- speed
When figuring out these properties on either longitudinal or transverse waves, it is necessary to remember the following:
Crests on a transverse wave are equal to compressions on a longitudinal wave
Troughs on a transverse wave are equal to rarefactions on a longitudinal wave
![Page 10: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/10.jpg)
AmplitudeAmplitude – the maximum distance the particles of a medium move from their rest position
For a transverse wave:
-- to find amplitude, you measure the height of the crest from the REST POSITION (or the depth of the trough)
For a longitudinal wave:
-- to find amplitude, you measure how strongly compressed the compressions are (or how far apart the rarefactions are spread)
amplitude
![Page 11: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/11.jpg)
WavelengthWavelength – how much of the medium is between corresponding parts of a repeating wave
-- wavelength is measured in meters, and is represented in formulas by the Greek letter lambda (λ)
For a transverse wave:-- you find wavelength by measuring the distance
between crests (or troughs)
For a longitudinal wave:
-- you find wavelength by measuring the distance between compressions (or rarefactions)
wavelength
![Page 12: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/12.jpg)
FrequencyFrequency – the number of complete waves that pass a specific point in a given amount of time (usually 1 second)
-- frequency is measured in a unit called Hertz (Hz), which is equal to waves/second (really is the unit per second)
-- frequency is represented by the Greek letter nu (ν)
To find the frequency of any wave, either count the number of crests or the number of compressions that pass a specific point in a given amount of time, then solve
Period – the amount of time it takes for one complete wave to pass
-- period is the inverse of frequency
Ex: If a wave has a frequency of 3 Hz (3 waves pass per second, then its period is 1/3 second (it takes 1/3 of a second for one wave to pass)
![Page 13: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/13.jpg)
SpeedThe speed of a wave is how much of a medium passes by a specific point in a given amount of time
-- speed is in the units of meters per second (m/s)
The speed of the wave is entirely determined by the medium through which the wave passes.
We can calculated wave speed with the following equation:
Speed = wavelength x frequency
OR
s = λ x ν
Of course: λ = (s / ν) and ν = (s / λ)
vs /
![Page 14: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/14.jpg)
Practice Problems1. An ocean wave passes a buoy 5 times in 20 seconds.
a) What is the frequency of this wave?
b) What is the period of this wave?
c) If the wave has a wavelength of 10 meters, what is the speed of this wave?
![Page 15: Waves. What Are Waves? Wave – a disturbance that transfers energy -- the energy transferred through a wave can be carried from the disturbance, through](https://reader035.vdocuments.site/reader035/viewer/2022070308/551bd1ae550346b9588b54f6/html5/thumbnails/15.jpg)
More Practice Problems2. The speed of a rope is 40 m/s and its wavelength is 5 m.
a) What is the frequency of this wave?
b) What is the period of this wave?
3. A wave with a period of 0.2 seconds travels at a speed of 60 m/s. What is the wavelength of this wave?