Waves
Day One
Frequency
The amount of waves that pass in the a certain amount of time, typically measured in hertzs (HZ)
Example: 3 waves per second is a lower frequency than 9 waves per second
Higher frequencies have more waves occuring in the same duration
Amplitude
The distance between the maximum or minimum of the wave in its rest position
The distance between rest and the through
The distance between rest and the peak
Trough
The lowest point of a transverse wave, the opposite of the Crest
It is always below the rest position, minimum of the wave
Crest
The highest point of a transverse wave, the opposite of the trough
It is always above the rest position, maximum of the wave
Wave-Length (Period Length)
The distance it takes for one wave to pass
From the crest of one wave to the crest of another
How long a wave is taking to go through a certain distance
Transverse Waves vs Longitudinal Waves
Transverse Waves
Where the movement of the waves is perpendicular to the direction of energy
They move in the opposite direction of energy
Longitudinal Waves
Where the movement of the waves is parallel to the direction of energy
They move in the same direction as the energy
Visible Spectrum
Violet, Indigo, Blue, Green, Yellow, Orange, Red
You cannot see anything besides these colors as above violet is Ultraviolet and below red is Infrared
Equations/Variables
C = 3 x 108 m/s
Wavelength is represented as (Lambda)
Wave
A disturbance in any medium
Day Two
Period
The amount of time it takes for one wave to pass a given point is known as the wave period, and it is inversely related to the frequency of the wave.
The amount of time for one cycle which is the passing of one crest and trough
Frequency (f)
1/T
One divided by time
Wavelength (λ)
v/f
Velocity divided by frequency
Velocity (v)
λf
Wavelength multiplied by frequency
Velocity of Sound
About 343 m/s
Velocity of Light
About 2.9998 or 3.0 x 108
Day Three
Wave Fronts
The waves that are formed when existing waves are disturbed, typically happening when waves move through a gap
If it is just one big stone then the wave bounces back
The amplitude influences the wavelength of the new waves formed
Higher amplitude means a larger wavelength
Lower amplitude means a smaller wavelength
Defraction
The spreading out of waves when they encournter a barrier
They are typycally circular waves (wave fronts) created through the small gap
Superposition
When two waves collide with each other they combine
If they are in the same phase then their amplitudes combine
If they are in the opposite phase then there is destructive interference
They cancel out each other
Phases
The point is oscillating the wave is in, which can be in or out of sync with other waves
Same
When two waves are on the same phase
They are at the same point in oscillating
Ex: Both at the crest
When two waves are in opposite phases
They are at opposite points in oscillating
One is at its crest and the other is at its trough
Day Four
Refraction
The process of where waves bend as they transiton between different mediums
This could change the direction and the shape of the wave
Left → Right or Straight → Curvy
Phases of Matter and Frequency
Gas < Liquid < Solid
Solid has the highest velocity, while gas has the lowest velocity
The higher the density of the object the higher the frequency
There is more disturbance
Doppler Effect
When the frequency or wavelength of a wave cahnges in relation to an observer ad their relative postion
As the distance decreases we can hear it louder, but as it increases it gets quieter
As it gets further the frequency decreases but when it gets closer the frequency increases
Equation
Fo = Fs x [(v ± vo) / (v ± vs)]
Fo = observed frequency
Fs = source frequency
v = velocity of wave
Speed of sound is 343 m/s
Speed of light is 3 x 108 m/s
vo = velocity of observer
vs = velocity of source
± = plus or minus
Add or Subtract?
If the observer and the source are moving towards each other we use the plus sign
If they are moving away fo each other then we use the minus sign
Day Five
Standing Wave
A wave that appears to be still, but is actually moving
It’s crest and trough switch places, creating the illusion that is not moving at all
A wave that has one or both ends fixed causing it to bounce back insteading of go continous
Antinodes vs Nodes
Antinodes
The parts of a standing wave that are moving, even if we don’t realize it
Most often the crest and the trough
As the name suggest, they are the opposite of nodes
Nodes
The parts of a standing wave that are not moving, which is what tricks us
The middle points, or in between two crest and two trough
There is always just one more node than antinoed
# Antinode + One = # Node
Harmonics
A componet frequency of an oscilation or a wave
In music, it is an accompaning tone from the base like in chords. This is also shown in waves as there is more than just one frequency.
Calculated by the amount of antinodes there are
1 Antinode = 1 Harmonic
2 Antinode = 2 Harmonic
3 Antinode = 3 Harmonic
Wave Pulse
A singular disturbance in a wave unlike the others
If most waves have a low amplitude it will have a high amplitude and vice versa
Day Six
Properties of Light Waves
Reflection
Reflection is the process where waves bounce back after hitting barrier or surface
It usually occurs when an incoming wave encounters a medium it can’t pass through
Ex: Water, A Mirror
Law of Reflection: Incident Rays equals Reflective Rays (OI = Or)
Incident Rays
The wave that is moving towards the mirror, and hits the mirror
Reflective Rays
The ray that bounces back from the mirror, and is moving away
Normal Rays
An imaginery ray or line that is perpendicular to the surface at the point of incidence
Angle of Incidence (OI + OR = 90 degrees)
The angle where the wave strikes the surface
It is always between the incident ray and the normal ray
Never measure the angle from the surface, always from the normal ray
Angle of Reflection
The angle where the wave moves away from the sruface
It is always between the normal ray and reflected ray
Never measure the angle from the surface, always from the normal ray
Refraction
Refraction is the process where a wave bends when it encounters a barrier or surface
Ex: When you put a pencil in water
Refractive Index (Index of Refraction)
The key factor in deciding the direction and speed of a light wave when it approaches a medium
Will it bounce back or will it bend?
Absorbtion
When the light aborbs the wave, usually converting the wave to a different kind of energy
Photons
Light is the only element that has wave nature and particle nature
The particle form of light are called photons