2 WAVES a disturbance that transfers energy Carries energy from one place to anotherClassified by what they move throughMechanical Waves the energy is transferred by vibrations of medium (medium = matter) ex/ ocean waves move through waterElectromagnetic waves (EM Waves) the energy moves through disturbances in the electromagnetic field.Physics The act or process of propagating, especially the process by which a disturbance, such as the motion of electromagnetic or sound waves, is transmitted through a medium such as air or water.A medium is a substance or material which carries the wave
3 WAVE STRUCTURE CREST (peak) AMPLITUDE resting to max peak WAVELENGTH TROUGH
4 MECHANICAL WAVESrequire a medium (the material through which the disturbance is moving) to transmit energytravel through & gradually lose energy to that mediumExamples:water, sound, rope, & spring wavesMechanical Media:water, air, rope, springMaking a pulse
5 MECHANICAL WAVES Classified by how medium vibrates Classified by how medium vibratesPulse = direction of energy transferVibration = direction of vibration of medium relative to pulse3 types:Longitudinal,transverse,surface
6 MECHANICAL WAVES Classified by how medium vibrates Longitudinal Waves: Vibration is in the same direction as wave pulse (parallel to wave pulse)Transverse Waves:Vibration is at 900 (right angles) to wave pulseSurface Waves:Vibration is circularEx/ Ocean waves; surface waves
7 TRANVERSE WAVES Sideways or up & down Examples: Vibration is perpendicular to the direction of the motion of the waveSideways or up & downExamples:S-type earthquake wavesElectromagnetic (EM) or light waves
8 LONGITUDINAL WAVESVibration is parallel to the direction of the motion of the waveBack and forth (compression & rarefraction)Also called compression or pressure waveExamples:P-type earthquake wavesSound wavesRarefraction (expansion)Compression
9 Waves describe the Earth P waves move through solids & liquidsP waves move through solids & liquidsS waves move through solids only!!!Are these MECHANICAL WAVES????YES!! Seismic waves need a medium (the earth!)
10 CHARACTERISTICS OF WAVES Waves are described according to theirAmplitude measures DISPLACEMENT size of the disturbanceWavelength distance of a “repeating unit” Also called a cycleVelocity v speed = how fast wave travels
11 AMPLITUDE Distance between “rest & crest” or “rest & trough” Gives indication of “power” or “strength” of wave (magnitude of earthquake = Richter scale)Does not affect velocity of waveDetermines loudness (sound) or brightness (EM wave)
12 WAVELENGTH Distance between any two repeating points on a wave crest-crest, trough-trough, expansion-expansion, compression-compressionDetermines what colors we see; what notes we hear (pitch)Shorter wavelengths have more cycles per minute because they aren’t as long
13 VELOCITY v the rate at which the energy travels; speed & direction Depends on mediumMechanical waves travel faster through dense mediumsEM Waves are faster through less dense mediums
14 Frequency ƒHow often number of wavelengths that pass any point per secondmeasured in wavelengths/second or cycles/second Hertz (Hz) = number of wavelengths in 1 secondFrequency is related to velocity: v = ƒ
15 PERIOD THow long Amount of time for one wavelength to pass a pointRelated inversely to frequencyPeriod = 1FrequencyWhen an event occurs repeatedly, then we say that the event is periodic and refer to the time for the event to repeat itself as the period.1 = T f
16 Internet resourcesTo test how well you understand go toWhen an event occurs repeatedly, then we say that the event is periodic and refer to the time for the event to repeat itself as the period.
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