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thanks everyone for helping

2007-03-01 13:09:37 · 32 answers · asked by thatsfunnybunny 2 in Science & Mathematics Physics

32 answers

When an ultrasonic pulse, containing, say, ten quasi-sinusoidal oscillations, is reflected in air from a rough surface, it is observed experimentally that the scattered wave train contains dislocations, which are closely analogous to those found in imperfect crystals. We show theoretically that such dislocations are to be expected whenever limited trains of waves, ultimately derived from the same oscillator, travel in different directions and interfere - for example in a scattering problem. Dispersion is not involved. Equations are given showing the detailed structure of edge, screw and mixed edge-screw dislocations, and also of parallel sets of such dislocations. Edge dislocations can glide relative to the wave train at any velocity; they can also climb, and screw dislocations can glide. Wavefront dislocations may be curved, and they may intersect; they may collide and rebound; they may annihilate each other or be created as loops or pairs. With dislocations in wave trains, unlike crystal dislocations, there is no breakdown of linearity near the centre. Mathematically they are lines along which the phase is indeterminate; this implies that the wave amplitude is zero.(for all types of waves)


The medium moves back and forth or up and down as a way to transmit the wave energy. Water moves up and down (actually in little circles) when a wave travels thru it; air moves back and forth in the direction of the sound traveling thru it - as does water when it transmits sound waves.The wave is a pressure band that propagates through the medium, but it does not cause the medium to move with it.(iff the medium taken is only water)

(but if the case is with light wave)
All types of waves known to that time traveled through some sort of medium: for instance, sound waves were propagated through air, water, or some other type of matter. If light was a wave, as Huygens said, then it, too, must have some medium. Huygens and his followers proposed a weak theory by suggesting the existence of an invisible substance called ether, which existed throughout the universe and which carried light.

Ether, of course, was really no answer at all. There was no evidence that it existed, and to many scientists, it was merely a concept invented to shore up an otherwise convincing argument. Then, in 1872, Scottish physicist James Clerk Maxwell (1831-1879) proposed a solution that must have surprised many scientists. The "medium" through which light travels, Maxwell proposed, was no medium at all; rather, the energy in light is transferred by means of radiation, which requires no medium.

2007-03-01 14:58:19 · answer #1 · answered by aaryan 2 · 1 0

Yes, but not in the way you might think. In a wave on the water, the water moves at right angled (up and down) to the direction of propagation. This is called a transverse wave. If the motion of the medium is inthe directions of the wave propagation and then returning to it's original position (such as a sound wave or a shock wave) it's called a longitudinal wave.

In the case of electromagnetic waves (radio, microwaves, light, etc.) there is no 'medium' involved, so the question is actually meaningless.


Doug

2007-03-01 15:14:17 · answer #2 · answered by doug_donaghue 7 · 0 0

Okay, say your medium was water. When a wave is created the water moves with the wave. But keep in mind that not all waves are physical. And not all waves travel through mediums. Take Radio waves as an example.

Hope this helps.

2007-03-01 15:01:12 · answer #3 · answered by daxter8230 1 · 0 0

There are two types of waves: Longitudinal and Transverse.
A wave is essentially the movement of energy from one place to another, using one of the waves above.
In both scenarios, the particles/individual atoms of the medium will only move up or down (Transverse) or parallel with the motion of the wave (Longitudinal).

Think of it this way: If you've ever seen a speaker work, you can see a cone inside the speaker vibrating. That cone pushes the air out at certain frequencies. The cone makes the particles next to it collide with other particles, creating sound waves. The particles that were displaced then goes back to its original position when the cone leaves because now there's a vacuum where the cone used to be.

2007-03-01 15:06:13 · answer #4 · answered by Anonymous · 0 0

When a wave travels through water the wave moves away from the point of origin while the water itself moves up and down as the wave passes through it.

2007-03-01 14:55:54 · answer #5 · answered by Anonymous · 0 0

No. The medium moves back and forth or up and down as a way to transmit the wave energy. Water moves up and down (actually in little circles) when a wave travels thru it; air moves back and forth in the direction of the sound traveling thru it - as does water when it transmits sound waves.

Think about it: sounds travels about 750 mph at sea level, but do you feel a 750 mph wind every time you hear something? The same goes for water waves, which can also travel hundreds of miles per hour, yet the ocean stays in one place and doesn't continually pile up on the land.

2007-03-01 14:53:18 · answer #6 · answered by hznfrst 6 · 0 0

No, the medium does not move along with the wave. The wave is a pressure band that propagates through the medium, but it does not cause the medium to move with it.

As a field experiment, go to the ocean and watch how waves work. A coconut floating on the sea simply goes up and down - not with the wave.

2007-03-01 14:44:21 · answer #7 · answered by lip11 3 · 6 0

The confusion is that the actual wave is energy put into the system. This energy moves thru a medium that is "fluid"enough to allow a smooth transfer. Stuff like water or air have a very low friction co-efficient so they transfer energy (sound, light) well. A steel plate can also carry energy, but not very far because of increased friction. Thus, as the energy is transferred thru the water, it moves the water out of its way. But then it can drop the water right back where it was, so that the water can appear to not have moved at all. It did move, when the energy was passing thru it. But once the energy is gone, it stops moving.

2007-03-01 14:46:22 · answer #8 · answered by Anonymous · 1 0

Contrary to the other posters, think about a cork in water. If waves pass by the cork, it will move up and down with the wave. But because the waves are also moving backward at the same time at the same intensity, the cork seems to merely bob up and down. There must be some greater wave force in one direction to push the cork towards shore, where the waves break.

Or think about this: When you hit a metal shovel on a post, you hear a sound because sound waves are traveling through the metal. You also feel vibrations in your arms because of that impetus. Do your arms and the metal move because of those waves? Something to think about.

2007-03-01 14:45:49 · answer #9 · answered by Anonymous · 2 0

in some cases, yes, but not necessarilly.

A wave is an energy form. The energy may interact with the medium it is traveling through and displace the medium, or the medium may resume its original state.

A water wave will cause the water to move.

Sound conducted in an iron pipe willl not cause the metal of the pipe to move in the direction the sound travels.

2007-03-01 14:54:00 · answer #10 · answered by Anonymous · 0 0

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