key idea #2: waves are produced by vibrations in matter. matter is anything that has mass and takes...
TRANSCRIPT
Key Idea #2: Waves are produced by vibrations in matter.
Matter is anything that has mass and takes up space.
A wave is a disturbance that transmits energy through matter and space.
http://www.isvr.soton.ac.uk/spcg/tutorial/tutorial/Tutorial_files/Web-basics-nature.htm
Mechanical waves are created when a source of energy causes a medium to vibrate.
The wave is the motion of a vibration.
FYI: In the above example the medium is a rope. Pick a
single particle and watch its motion. Notice that the medium itself doesn’t go anywhere.
The individual atoms and molecules in the medium oscillate about their equilibrium (rest) position, but their average position does not change.
As they interact with their neighbors, they transfer some of their energy to them.
FYI The neighboring atoms in turn transfer this
energy to their neighbors down the line. In this way the energy is transported
throughout the medium, NOT the particles of matter.
A vibration is a repeated back-and-forth or up-and-down motion.
http://www.isvr.soton.ac.uk/spcg/tutorial/tutorial/Tutorial_files/Web-basics-nature.htm
When molecules in matter vibrate, they cause other molecules to vibrate.
This causes waves to travel outward from the center of the vibration.
emusictips.com
An energy transfer takes place when molecules transfer the energy of motion to other molecules then return to their state of rest.
http://shadow.yak.net/15share.ehs.uen.org
Characteristics of Waves
Wavelength Frequency Amplitude
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A wavelength is the distance between two corresponding parts on
a wave.
turningthesolomonkey.com
The amplitude of a wave is a direct measure of its energy.
The greater the energy, the greater the wave’s amplitude is.
Amplitude
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The number of complete waves that pass given point in a certain amount of time.
The number of vibrations per second.
Example: If you make a wave in a rope so that 7 waves pass every second, it’s frequency is 7 waves per second.
Frequency
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Same amplitude Same amounts of energy
Different frequencies Different vibrations per second.
Same frequency Same number of vibrations per
second. Different amplitudes
Different amounts of energy.
Amplitude and Frequency
education.com
These three waves have the same frequency but different amplitudes.
Amplitude determines the loudness of the sound.
The higher the amplitude, the louder the sound.
nasa.gov
These waves have different amplitudes and frequencies.
Amplitude and Frequency http://www.classzone.com/books/m
l_science_share/vis_sim/wslm05_pg18_graph/wslm05_pg18_graph.html
Frequency and Pitch High frequency = high pitch Low frequency = low pitch
Examples
Vibrating Ruler Short ruler=faster vibration=high frequency=high
pitch Long ruler=slower vibration=low frequency=low
pitch
String Instruments On string instruments thicker, heavier strings
vibrate more slowly than thinner strings The slower the vibration, the lower the pitch. The faster the vibration, the higher the pitch.
The Nature of Waves
How waves transfer energy:
When a tuning fork is placed in the water, ripples (waves) are seen coming away from the tuning fork in even rings.
http://www.google.com/imgres?imgurl=http://farm3.static.flickr.com/2589/3833077029_7c2329c700.jpg&imgrefurl=http://flickr.com/photos/zebraheart123/3833077029/&usg=__Z-v6J7yVPBhINHBpgaGZ83pRnz4=&h=328&w=500&sz=99&hl=en&start=70&zoom=0&tbnid=KSGsB6bPyo3odM:&tbnh=85&tbnw=130&prev=/images%3Fq%3Dtuning%2Bfork%2Bin%2Bwater%26um%3D1%26hl%3Den%26sa%3DG%26biw%3D1003%26bih%3D550%26tbs%3Disch:10%2C2024&um=1&itbs=1&iact=hc&vpx=165&vpy=137&dur=125&hovh=85&hovw=130&tx=116&ty=48&ei=FQmQTPezL4uInQfOrNW0DA&oei=AgiQTK3VMszsnQf34vy0DA&esq=12&page=5&ndsp=17&ved=1t:429,r:11,s:70&biw=1003&bih=550
When waves hit a beach, erosion takes place.
Ripples are left in the sand to show the reaction of the wave.
http://www.google.com/imgres?imgurl=http://farm4.static.flickr.com/3554/3574142548_733bc694c6_o.jpg&imgrefurl=http://flickr.com/photos/27998757%40N07/3574142548&usg=__JvJZwuBP3n5mWFxT5HOZ4AjQrf8=&h=683&w=1024&sz=699&hl=en&start=155&zoom=0&tbnid=5ebH6rCYsfEidM:&tbnh=100&tbnw=150&prev=/images%3Fq%3Dbeach%2Bsand%2Bripples%26um%3D1%26hl%3Den%26sa%3DG%26biw%3D1003%26bih%3D550%26tbs%3Disch:10%2C4171&um=1&itbs=1&iact=hc&vpx=523&vpy=327&dur=31&hovh=100&hovw=150&tx=78&ty=88&ei=7QyQTO-PLczAnAfmwPC0DA&oei=0wyQTMHsB9GTnQe908G0DA&esq=11&page=11&ndsp=15&ved=1t:429,r:2,s:155&biw=1003&bih=550
Seismic waves are vibrations that travel through the Earth carrying the energy of motion released during an earthquake.
When seismic waves travel through the Earth, the vibrations are transferred outward from the origin of the quake.
http://www.google.com/imgres?imgurl=http://www.physicalgeography.net/fundamentals/images/epicenter.gif&imgrefurl=http://www.physicalgeography.net/fundamentals/10m.html&usg=__GyFBnTPrAKTr9DHVTMwYp9bht4M=&h=304&w=372&sz=22&hl=en&start=0&zoom=1&tbnid=vS5JbAKvROSzCM:&tbnh=115&tbnw=141&prev=/images%3Fq%3Dearthquake%2Bseismic%2Bwaves%26um%3D1%26hl%3Den%26biw%3D1003%26bih%3D550%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=94&ei=9Q6QTImjG8nonQfFyby0DA&oei=9Q6QTImjG8nonQfFyby0DA&esq=1&page=1&ndsp=17&ved=1t:429,r:1,s:0&tx=75&ty=53
Seismic waves are strong enough to cause the ground to tremble and buildings to shake and
crumble.
Strangevehicles.com
http://science.nationalgeographic.com/science/enlarge/earthquake-damage.html
Libcom.org