Waves Waves rhythmic disturbances vibrations that transfer energy through matter or space carry energy from one place to another Very disturbing Waves Water Waves How does the video display what a wave is ID: 635770
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Slide1
WAVESHow does energy travel?Slide2
WavesWavesrhythmic disturbances (vibrations) that transfer energy through matter or space carry energy from one place to another
Very disturbing!Slide3
WavesWater WavesHow does the video display what a wave is?Transfers energy from water to peopleSlide4
WavesTuning Fork DemoHow does the demo display what a wave is?Transfers energy from
fork to waterSlide5
WavesEarthquakeHow does the video of an earthquake in Japan display what a wave is?Transfers energy from seismic wave in earth (earthquake) to buildingSlide6
Classes of WavesOne way to distinguish between different waves is by what they move through or their medium Medium: material through which a wave transfers energysolid, liquid, gas, or combinationsome waves require no mediumTypes of waves based on medium:
mechanical waves
electromagnetic wavesSlide7
Mechanical WavesMechanical waves:waves that require a mediumparticles of the medium must vibrate in order for energy to be transferred Examples:Water wavesSound wavesSeismic waves (earthquakes)Slide8
Electromagnetic WavesElectromagnetic waves:waves that do not require a mediumcan travel through empty space or matterEmpty space: where matter isn’t presentExamples:radio wavesmicrowaves
infrared waves
visible light
ultraviolet waves
X-raysGamma raysSlide9
More Classes of Waves
Not all
waves
transfer energy the same
way
Waves can be classified by comparing the
direction of particles
in the medium to move with the direction in which the wave moves
.
Two classes of waves:
Transverse
LongitudinalSlide10
Making WavesWith your group members, try to make each class of waves using the provided slinkyTransverse LongitudinalSlide11
Slinky Wave LabWith a partner you will discover some more about energy waves!Slide12
Slinky Wave Lab Conclusions1.) What moves down the slinky as the wave propagates (propagates means ‘moves forward’)?
Energy
2.) According
to the law of conservation of energy, energy cannot be created or destroyed. If so, what is the source of energy that created the wave in this lab?
Your
hand (mechanical energy) 3
.)
Once the energy enters the slinky at your hand, where does it go?
Down the
slinky to the other personSlide13
If the energy is moving from your hand to the slinky from one end of it to the other
4.) In what direction does the medium (look at piece of tape) move compared to the energy of the wave in a transverse wave?
Perpendicular to
(90 degree angle)5.) ...Longitudinal wave?
Parallel to
(same direction)
Slinky Wave Lab ConclusionsSlide14
6.) What can we conclude about the speed of a wave when you change the size of the pulse?The speed of a wave stays the same regardless of the size of the pulse7.) What factor do you think could affect the speed of a wave? The medium
Slinky Wave Lab ConclusionsSlide15
8.) What happens to the number of waves between two points when you increase the rate of pulses?More waves9.) What happens to the width of the waves between two points when you increase the rate of the pulsesThe width decreases
Slinky Wave Lab ConclusionsSlide16
Transverse Wave of PeopleThe entire class will form a transverse pulse. Stand shoulder to shoulder in a straight line. Create a stadium wave. When the pulse travels through you, which way did you move?How does this compare to the transverse wave of the slinky?Slide17
Transverse WavesTransverse waves:a wave in which the medium moves perpendicular to the direction of wave motionexamples: electromagnetic waves, strings on an instrument, some seismic wavesSlide18
Anatomy of a Transverse WavesCrest- highest point of transverse waveTrough- lowest point of transverse wave
W
avelength
- distance from one point on a wave to the corresponding point on the next waveSlide19
Longitudinal Wave of PeopleThe entire class will form a longitudinal wave. Line up in a single file. Place your hands on the shoulders of the person in front of you. The person at the back of the line will send some energy to the person at the front of the line by nudging the person in front of them. When the pulse travels through you, which way do you move? When the pulse travels through you, which way did you move?
How does this compare to the longitudinal wave of the slinky?Slide20
Longitudinal WavesLongitudinal waves:a wave in which the particles of medium vibrate back in forth in the same direction as (parallel to) the wave
also called
compressional waves
Examples: Sound, some seismic wavesSlide21
Anatomy of a Longitudinal WavesCompression- Where the particles of the medium are close together (more dense)Rarefaction- Where the particles of the medium are further apart (less dense)
rarefaction
compression
wavelength
wavelength