Wave Properties 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

Compressional or Longitudinal Wave

Frequency = 1 full wavelength 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 Equation: Frequency = # waves/time Measured in Hertz (Hz) http://id.mind.net/~zona/mstm/physics/waves/partsOfAWave/waveParts.htm#frequency shorter WAVELENGTHS = Greater ENERGY = Higher FREQUENCY Longer w a v e l e n g t h s = Less energy = smaller frequency

Higher Frequency Lower Frequency

Amplitude Greater amplitude = greater energy Amplitude is a measure of the distance between a line through the middle of wave and a crest or trough. (half the height) Greater amplitude = greater energy

Neither: same frequency (# WL/time) 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.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 Sound waves travel faster through denser mediums. The sound wave will travel the fastest through which medium? Air Water Wood Steel

www.acoustics.salford.ac.uk/schools/lesson1/flash/speed.swf

Wave Type Speed Sound Waves 330 m/s (3.3 x 102 m/s) Radio Waves 300,000,000 m/s (3.0 x 108 m/s)

The GREATER the energy Remember The smaller the wavelength The GREATER the FREQUENCY The GREATER the AMPLITUDE

Determining the number of wavelengths… precursor to reading diagrams and graphs

1 wavelength

1.5 wavelengths

2 wavelengths

How many wavelengths? 3

How many wavelengths?

#1 answer (3.5)

How many wavelengths?

#2 answer (6)

How many wavelengths?

#3 answer (5.5)

Determining Frequency from a graph

Frequency = #of waves/time Frequency Equation Frequency = #of waves/time Measured in Hertz (Hz)

3 waves 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds

from 0 to 12 seconds 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds

Frequency = 3 cycles/12 s = 0.25 Hz 4 5 6 7 8 9 10 11 12 1 3 Time in seconds

1 cycle in 4 seconds= 0.25 Hz 2 4 5 6 7 8 9 10 11 12 1 3 Time in seconds

Frequency = 1 wave cycle / 4 seconds = 0.25 Hz 6 7 8 9 10 11 12 1 3 Time in seconds

What is the frequency? 8 10 14 20 22 24 2 4 6 12 16 18 Time in seconds

Frequency? 3 waves/ 24 s= 1/8 Hz 0 to 24 seconds 3 waves 8 10 14 20 22 2 4 6 12 16 18 Time in seconds

Frequency = 1 cycle in 8 seconds= 1/8 Hz 10 14 20 22 24 2 4 6 12 16 18 Time in seconds

#1 frequency= ? 1 2 3 4 5 6 7 8 9 10 11 12 Time seconds

#1 f= 1/8 Hz 6 7 8 9 10 1 2 3 4 5 11 12 Time seconds

#2 frequency= ? 18 20 22 22 24 2 6 8 10 12 14 16 26 4 Time seconds

#2 f= 1/8 Hz 18 20 22 22 24 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 10 15 Time seconds

#3 f = 1/20 Hz 40 45 50 55 5 20 25 30 35 60 65 70 10 15 Time seconds

E)Type of Wave: A B Transverse E C D