Anatomy of a wave

a wavelength measurement is made by measuring the distance from a compression to the next compression or from a rarefaction to the next rarefaction. A region where the coils are pressed together in a small amount of space is known as a compression. A compression is a point on a medium through which a longitudinal wave is traveling that has the maximum density. A region where the coils are spread apart, thus maximizing the distance between coils, is known as a rarefaction. A rarefaction is a point on a medium through which a longitudinal wave is traveling that has the minimum density. Longitudinal Wave

Dotted line= equilibrium Transverse Wave The amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position. In a sense, the amplitude is the distance from rest to crest. The crest of a wave is the point on the medium that exhibits the maximum amount of positive or upward displacement from the rest position. Dotted line= equilibrium The trough of a wave is the point on the medium that exhibits the maximum amount of negative or downward displacement from the rest position. The wavelength of a wave is simply the length of one complete wave cycle. (from crest to crest)

Amplitude The amount of energy carried by a wave (wave height)

The energy of a mechanical wave depends on the material Heavy rope: You need more initial force in order to get the same amplitude Light rope: You need less initial force in order to get the same amplitude

frequency The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium. The number of complete vibrational cycles of a medium per a given amount of time. units of cycles/second, waves/second, vibrations/second, or something/second Or Hertz (abbreviated Hz) where 1 Hz is equivalent to 1 cycle/second. High frequency Low frequency High pitch sounds will have a high frequency and low pitch sounds will have a low frequency

Wavelength The length of one complete wave cycle Wavelength (λ) = speed (v) / frequency (f) Long wavelength Short wavelength

Sound Waves Volume or amplitude will be measured in Decibels. Lower amplitude Higher amplitude Sound Waves Longer wavelength, lower frequency Shorter wavelength, higher frequency

Speed= wavelength * frequency For a wave, the speed is the distance traveled by a given point on the wave (such as a crest) in a given period of time. Speed= wavelength * frequency So while wave frequency refers to the number of cycles occurring per second, wave speed refers to the meters traveled per second. Example: You can take long steps very slowly, or you can take long steps quickly. Length of step=wavelength Number of steps per second= frequency To find your speed, you need to consider your length of step as well as how often/quickly you are taking them.

Speed can be affected by the type of medium the wave is moving through Waves move faster through solids Waves move slower through gases The more dense the medium , the easier it is for the energy to pass through. Example: think about sound waves. Whale songs can be heard for upwards of 10,000 miles underwater, whereas sound traveling through the air don’t travel even a fraction of that distance at the same frequency.

Simulations

sources http://abernathyscience.com/online%20labs/trans http://opwx.db.erau.edu/faculty/mullerb/Wx365/Sat_HTML_notes_files/wavelength.gif http://www.cartage.org.lb/en/themes/Sciences/Physics/Acoustics/General/Wavelength2/freq-wavelength.jpg http://www.mapfre.com/fundacion/html/revistas/seguridad/n124/img/art_1_03En.jpg http://3.bp.blogspot.com/-BAgHbfLAd6w/UT-_dTXnNkI/AAAAAAAAASI/dGmJoiUG1uA/s1600/Longitudinal+Wave.png http://getfitwithles.files.wordpress.com/2012/01/battling-ropes.jpg http://www.fas.harvard.edu/~scdiroff/lds/OscillationsWaves/StandingWaveonSpring/StandingWaveonSpring002.gif