waves. what do these things have in common?
TRANSCRIPT
WAVES
What do these things have in
common?
Think about what characteristics make these things similar and
write them down.
Characteristics of a Wave
Amplitude, A - the maximum displacement of wave
Characteristics of a Wave
Period, T -the time it takes to complete one cycle in seconds
Characteristics of a Wave
Frequency, f -number of cycles/vibrations per unit of time. Unit is Hz - Hertz
High f
Low f
Characteristic of a Wave
• Wavelength, λ, length of a wave measured in meters.
Relationship between period and frequency- it’s complicated…
f = 1 / T frequency = 1 / Period
or
T = 1 / fPeriod = 1 / frequency
Types of Waves
LongitudinalParticles in the wave move parallel to the motion of the wave.
TransverseParticles in the wave move perpendicular to the motion of the wave.
Characteristics of Wave Types
LongitudinalCompression, rarefraction (stretching), wavelengths λ
TransverseCrests, troughs, wavelengths λ
Draw Wave
Label• Crests• Troughs• Wavelengths• Period• Amplitude
Transverse
Draw Wave
Label• Compression• Rarefractions• Wavelengths• Period• Amplitude
Longitudinal
Speed of Wave
Speed = distance / time
Speed = amount of distance a wave travels / time it takes the wave to cover that distance
Example
Mac and Tosh are resting on top of the water near the end of the pool when Mac creates a surface wave. The wave travels the length of the pool and back in 25 seconds. The pool is 25 meters long. Determine the speed of the wave.
Example
The period of a wave is 0.0300 seconds. It travels at a velocity of 10.0 m/s. Determine the frequency and the wavelength of the wave.
STANDING WAVES
A standing wave is a traverse wave that does not travel. For this to happen, both ends of the waves need to be attached to something.
Standing wave
Standing wave
http://www.acs.psu.edu/drussell/Demos/StandingWaves/StandingWaves.html
Nodes and antinodes
• Nodes- places of no displacement on a wave• Antinodes – midway between nodes and a
place where displacement is at a maximum
How many nodes/antinodes?
• 5 nodes• 4 antinodes
How many nodes/antinodes?
• Nodes?• Antinodes?
Interference
• Interference is when waves add or subtract and interact with each other
Types of Interference
CONSTRUCTIVE• Adding up of waves
DESTRUCTIVE• Subtracting waves
What kind of interference?
Superposition Principle- the addition of waves
http://www.sciencejoywagon.com/physicszone/09waves/
http://www.feilding.net/sfuad/musi3012-01/html/lectures/004_sound_III.htm