### Waves

Objectives
• Identify how waves transfer energy without transferring matter
• Contrast transverse and longitudinal waves
• Relate wave speed, wavelength, and frequency
• Relate a wave's speed to the medium in which the wave travels
• Describe how waves are reflected and refracted at boundaries between media
• Apply the principle of superposition to the phenomenon of interference

All the important parts of a wave:
Vocab

• Refraction- the change in direction of waves at the boundary between two different media
• Interference- occurs when two or more waves move through a medium at the same time
• Trough- the low point on a wave
• Crest- the high point on a wave
• Wavelength- the shortest distance between points where the wave pattern repeats itself
• Frequency- the number of complete oscillations a wave makes each second
• Wave- disturbance that carries energy through matter or space
• Wave pulse- a single bump or disturbance that travels through a medium
• Periodic wave- a wave that moves up and down at the same rate
• Transverse wave-a wave that vibrates perpendicular to the direction of wave motion
• Longitudinal wave- disturbance that is parallel to the direction of wave motion
• Surface wave- particles move in a direction  both parallel and perendicular  to the direction of wave motion
• Incident wave- wave that hits the boundary
• Reflected wave- the returning wave
• Node- point on a wave that does not move
• Antinode- point on a wave with the largest displacement
• Standing Wave- a wave that appears to be still
•

Here you can see what the period and frequency of a wave are and how they are related.

How does the amplitude and frequency effect sound? Look up! To the left are some examples of how waves differ between insterments.

This picture shows the reflection of a ray and how a wave acts as it reflects.

Equations:

V= 340 m/s (sound)

Loudness- Sound intensity and intensity level
Intensity: I=P/A Intensity Level: B=10 log(I/Io)
Threshold of hearing: 10= 1x10^-16 W/m^2

Hooke's Law:
F = -kx

 This shows the difference between transverse waves and longitudinal waves and how they act (Up and down vs Left and right motion).     This picture shows the diffraction of a wave and how it curves around the edges of an opening in a barrier.      This shows the the property of refraction. Since the light rays travel at a different speed through water then they do air, it creates a different perception of where the object is.  This diagram shows the difference between constructive and destructive interference, how waves in phase create a larger amplitude and waves with equal but opposite amplitudes cancel each other out.