2What are waves?Def. - Disturbances that carry energy from place to place, through matter or space.
3Waves are made when you speak And heard when you listen Waves can travel through spaceMost waves begin with a vibrationWaves are made when you speakAnd heard when you listenWaves can make the earth move and shakeAnd make the light you see
4is the material in which a wave moves gasLiquidA medium can be a:Music from your radio to your earHow dolphins communicatesolidwood of a guitarMediumis the material in which a wave moves
5The medium can move in two ways: Motion of MediumEnergy moves through the medium. The medium just vibrates back and forth and doesn’t move with the wave.The medium can move in two ways:1. Transverse waves2. Longitudinal waves
6Medium moves at right angles to the direction of the wave. Transverse wavesMedium moves at right angles to the direction of the wave.Ex) football stadium waveA) Crest: highest pointB) Trough: lowest point
7Rest position or Parts of a Transverse Wave Crest Amplitude Trough WavelengthAmplitudeRest positionorTrough
8A) Compressions: where the molecules are crowded together Longitudinal wavesMedium moves parallel to the direction of the wave Ex. – a “slinky” or metal springMade up of:A) Compressions: where the molecules are crowded togetherB) Rarefactions: where the molecules spread apart.
9Compression Compression Rarefaction Parts of a Longitudinal wave Wavelength:CompressionCompression + RarefactionCompressionRarefaction
10Wave characteristicsWavelength: the distance between a point on one wave and the identical point on the next. (crest to crest, compression to compression)Unit: meterSymbol: l Lambda
11Directly related to the amount of energy carried. AmplitudeDef: the distance from the crest or trough of a wave to the rest position.Directly related to the amount of energy carried.
12If 3 waves went by in 1 second… You have 3 waves per Second Frequency: the # of waves that pass one place each second.Unit: hertz (Hz)If 3 waves went by in 1 second…You have 3 waves per SecondFrequency would be 3 Hz
31Refraction Why does the pencil appear to be broken when placed in a beaker of water??
32Diffraction: Bending of waves around the edge of a barrier
33There are two types of Wave interference: 1. Constructive Interference Def. - Interference is the result of two or more waves passing through a medium at the same time.There are two types of Wave interference:1. Constructive Interference2. Destructive Interference
34Wave interferenceConstructive Interference: two crests meet and make a wave with a bigger amplitude.
35Wave interferenceDestructive Interference: one crest & one trough meet and make a wave with a smaller amplitude..
41Sonograms: Ultrasonic waves (about 20,000 Hz) used to create images of fetuses in the womb Regular sonogram D sonogram
42Supersonic: faster than the speed of sound. Transonic: where only some parts of the air around an object (such as the ends of rotor blades) reach supersonic speeds (typically somewhere between Mach 0.8 and Mach 1.2).A US Navy F/A-18E/F Super Hornet in Transonic Flight
43An equal mixture of all frequencies of sound White NoiseAn equal mixture of all frequencies of sound
44Change in pitch due to motion. DopplereffectChange in pitch due to motion.
45*moving towards increases the pitch *moving away decreases the pitch Dopplereffect*moving towards increases the pitch*moving away decreases the pitchzoomNew word for the day: Dopeler Effect (n) The tendency of stupid ideas to seem smarter when they come at you rapidly.
46Large Amplitude = Loud sound Small Amplitude = Soft sound IntensityAmount of energymeasured in decibels (dB)Depends on the amplitude of sound waves.Large Amplitude = Loud soundSmall Amplitude = Soft sound
47Measurement of loudness DecibelsNear total silence - 0 dBA whisper - 15 dBNormal conversation - 60 dBLawnmower - 90 dBThreshold of pain dBA rock concert or a jet engine dBGunshot, firecracker dB
48A sound tube designed to decrease roadway noise Noise PollutionDispleasing sounds that disrupt the activity or happiness of human or animal life.Causes:Damage to the earStressHearing LossA sound tube designed to decrease roadway noise