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Wave Properties. 8-6.3 Summarize factors that influence the basic properties of waves (including frequency, amplitude, wavelength, and speed). Factors that Influence Wave Properties. Wavelength Frequency Amplitude Speed. Wavelength.
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Wave Properties 8-6.3 Summarize factors that influence the basic properties of waves (including frequency, amplitude, wavelength, and speed)
Factors that Influence Wave Properties • Wavelength • Frequency • Amplitude • Speed
Wavelength • Wavelength is the distance between one point on a wave and the nearest point just like it. • The measure of the distance between two successive identical parts of a wave (crest to crest in for transverse, compression to compression for compressional/longitudinal) • www.acoustics.salford.ac.uk/schools/lesson1/flash/wavelength.swf
Shorter Wavelength Longer Wavelength
Frequency • Frequency is the number of full wavelengths that pass a point each second. • Measures how rapidly vibrations occur in the medium, at the source of the wave, or both. • www.acoustics.salford.ac.uk/schools/lesson1/flash/freq.swf = 1 full wavelength
Frequency • Measured in Hertz (Hz) • Equation: • Frequency = # cycles/time • http://id.mind.net/~zona/mstm/physics/waves/partsOfAWave/waveParts.htm#frequency shorter WAVELENGTHS = Greater ENERGY = Higher FREQUENCY Longer w a velengths = Less energy = smaller frequency
Higher Frequency Lower Frequency
Amplitude • Amplitude is a measure of the distance between a line through the middle of wave and a crest or trough. (half the height) • Amplitude is the greatest distance that vibrations in a wave move from their normal position when a wave passes by. Greater amplitude = greater energy
What kind of wave is shown? • How many wavelengths are shown? • Which wave has less energy, A or B? • Which wave has greater frequency, A or B? transverse 2 B Neither: same frequency (# WL/time)
What is the amplitude? Amplitude = 0.75 Amplitude =1.0
http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.htmlhttp://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html
Speed • Speed is the distance a wave travels per time • Wave speed is determined by • Type of wave • Nature of medium • Waves travel at different speeds through different mediums. • As a wave enters a different medium, the wave’s speed changes. • All electromagnetic waves travel at the same speed in empty space: • 300 million m/s!
Speed Waves travel faster through denser mediums. • The sound wave will travel the fastest through which medium? • Air • Water • Wood • Steel
Determining the number of wavelengths… precursor to reading diagrams and graphs
Frequency Equation • Frequency = #of cycles/time • Measured in Hertz (Hz)
3 cycles 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds
from 0 to 12 seconds 0 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds
Frequency = 3 cycles/12 s = 0.25 Hz 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds
1 cycle in 4 seconds= 0.25 Hz 0 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds
Period symbol T • The time for 1 cycle
Frequency = 1 wave cycle / 4 seconds = 0.25 Hz 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds
What is the frequency? 8 10 14 20 22 24 0 2 4 6 12 16 18 Time in seconds
Frequency? 0 to 24 seconds 3 cycles 3 cycles / 24 s= 1/8 Hz 8 10 14 20 22 24 0 2 4 6 12 16 18 Time in seconds
OR • Frequency – 1 cycle in x seconds
Frequency =1 cycle in 8 seconds= 1/8 Hz 8 10 14 20 22 24 0 2 4 6 12 16 18 Time in seconds
#1 frequency= ? 6 7 8 9 10 12 0 1 2 3 4 5 11 Time seconds
#1 f= 1/8 Hz 6 7 8 9 10 0 1 2 3 4 5 11 12 Time seconds
#2 frequency= ? 18 20 22 22 24 0 2 6 8 10 12 14 16 26 4 Time seconds
#2 f= 1/8 Hz 18 20 22 22 24 0 2 6 8 10 12 14 16 26 4 Time seconds
#3 frequency = ? 40 45 50 55 5 20 25 30 35 60 65 70 0 10 15 Time seconds
#3 f = 1/20 Hz 40 45 50 55 5 20 25 30 35 60 65 70 0 10 15 Time seconds
E)Type of Wave: A B Transverse E C D