1. What are waves?

3. What are waves?
Water waves are just one of many kinds of waves. Sound and light are also waves.
Waves are caused by vibrations of a medium. A medium is the material through which a wave can travel.
Waves transfer energy from one place to another.
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4. There are two main types of waves
Waves are classified by what they are travel through...
SO……
There are two main types of waves
Mechanical waves
Electromagnetic waves

5. What are some types of waves?
Waves such as water waves that require a medium are called mechanical waves.
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6. Mechanical Waves
Some mechanical waves can travel through more than one medium.
For example, sound waves can move through air, water, and a solid wall.
Mechanical waves can’t travel without a medium.
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7. Electromagnetic Waves
Electromagnetic (EM) waves are not disturbances in a physical medium. They are vibrations of electric and magnetic fields.
Sunlight is an example of EM waves. Other examples include radio waves, microwaves, and X-rays.
In empty space, all EM waves travel at the same speed, called the speed of light.
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8. 2 main ways to transfer energy
Waves can be classified by comparing the direction that they cause particles in the medium to move with the direction in which the wave moves.
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9. How do waves transfer energy?
Energy can be transferred from one object to another using compressions and rarefactions. This causes energy to travel in a longitudinal wave.
Compressions – the energy is close together
Rarefactions-the energy is separated
Sound waves
travel parallel
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10. How do waves transfer energy?
Energy can be transferred from one object to another using up and down motions. This causes energy to travel as a transverse wave.
In a transverse wave, particles move perpendicularly to the direction the wave travels.
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11. Characteristics of waves

12. Crests and Troughs
The points where a wave is highest are called crests. The points where a wave is lowest are called troughs.
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13. Amplitude: Distance between “rest & crest” or “rest & trough”
Gives indication of “power” or “strength” of wave
Does not affect velocity of wave
Determines loudness (sound) or brightness (EM wave)

14. Wavelength:
Distance between any two repeating points on a wave crest-crest, trough-trough, expansion-expansion, compression-compression
Determines what colors we see; what notes we hear (pitch)
Shorter wavelengths have more cycles per minute because they aren’t as long

15. Velocity The rate at which energy travels Depends on the medium
Mechanical waves travel faster through dense mediums
EM Waves are faster through less dense mediums

16. Frequency:
number of wavelengths that pass any point per second
measured in wavelengths/second or cycles/second Hertz (Hz) = number of wavelengths in 1 second
Frequency is related to velocity: v = ƒ 

17. Period
Amount of time it takes for one wavelength to pass a point
Period =
Frequency