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jerry0696
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i had always belived that sound wave was a longitudinal wave till i come across something saying that its a transverse wave in solid.can anyone explain is it so??
jerry0696 said:i had always belived that sound wave was a longitudinal wave till i come across something saying that its a transverse wave in solid.can anyone explain is it so??
phyzguy said:In a fluid like air, sound waves are only longitudinal, since fluids don't support shear forces. Solids support both longitudinal and transverse sound waves, and they typically travel at different speeds.
jerry0696 said:if solid support both does that mean that sound is a transverse wave in solids??
jerry0696 said:does that mean that sound is a transverse wave in solids??
jtbell said:Sound can be a transverse wave in a solid, but it doesn't have to be transverse. It can be longitudinal instead, like in a gas or liquid.
However, at the surface of a solid, sound is transverse. The surface is a like a membrane, its oscillations can only be transverse
davenn said:Am desperately trying to picture that
any further info please ?
voko said:Inside a solid, sounds is longitudinal. However, at the surface of a solid, sound is transverse. The surface is a like a membrane, its oscillations can only be transverse.
Dadface said:There are different modes of vibration in solids but only those that can set up longitudinal waves in the surroundings are related to sound.
Dadface said:The eardrum can be considered as a membrane and this responds most strongly to longitudinal vibrations. It is sound that's being discussed,not vibrations in general.
Dadface said:I think the answer to the OPs question is no. Sound waves are longitudinal and not transverse. By definition sound waves are related to those types of waves that can be sensed by the ear and the ear drum reacts to longitudinal vibrations.
A solid may be able to vibrate in different ways but only the longitudinal components of those vibrations can be transferred to any surrounding air as sound waves. It reminds me of the longitudinal and transverse vibrations that can be set up on a stretched string. Both set up longitudinal vibrations (sound waves) in the surrounding air.
voko said:What's your definition of "sound"? And why is your definition relevant for me or anyone else?
Dadface said:Vibrations which travel through the air or another medium and are sensed by the ear.
The relevant part of this discussion is that the vibrations "are sensed by the ear" and the ear responds to longitudinal vibrations.
I think it's well understood by all here that ultrasound is sound and we could go for more detailed definitions such as defining "sounds which are audible to humans" or to bats or to any other animal species. But I don't want to get involved in semantics but want to see OPs question answered at a suitable level.voko said:So ultrasound is not sound then?
Dadface said:I'm assuming that the OP is currently at a level which is equivelent to GCSE or perhaps AS or A level (UK qualifications).If so the specifications require that students should understand that....."Sound waves are longitudinal" (P1.5.1b AQA physics)
AlephZero said:I can't be bothered to read what the AQA says this week (and they will probably say something different next week), but as sophiecentaur said, the bald statement "Sound waves are longitudina" will satisfy the kid with no interest in science who wants to scrape a C grade (and it will also satisfy teachers with the same objectives!) - but if a bright kid actually plucks a guitar string (or even twangs a ruler on a desk) and observes what happens, he or she is likely to get confused![/QUOTE
Where are you getting this information from? In AS specs kids study SHM and waves in strings in considerable detail.They know that both transverse as well as longitudinal vibrations of the string the ruler, or whatever it is sets up longitudinal waves in the surroundings which, depending on the frequency, can be detected as sound. I rarely see anyone get confused by that. Have you actually met any teachers who have the objectives you referred to?
sophiecentaur said:I am not suggesting that the specs should go into classification. Quite the reverse, (in fact have you read what I have written about classification?). I say that they should just state things clearly and unambiguously and give adequate, watertight definitions. If there is possible doubt, then things should be made clearer. How can you say that there is a "right level" for the course when the information is, in fact, incorrect or inadequate.? Which level of student are your remarks aimed at? The GCSE course is supposed to be aimed at all levels. The modern specifications are so inconsistent. On the same page, they refer to the most sophisticated of modern Science concepts and also use the sloppiest terms to discuss the very basic fundamentals of Science.
That reptile Gove has said so many things about British education that are perfectly accurate and people who support the present, flawed system are just giving him more excuses for his barbaric plans for change. Perhaps you are one of his fans?
You cannot predict how a bright student will receive a piece of badly stated information. It will be the bright student who sees the holes in inadequate teaching and will suffer because of them. The specifications are written, largely with a view to the lowest common denominator of the (non-specialist) staff who are required to deliver the stuff and not to the highest ability students.
These forums are littered with questions from students who have been confused because the information (the trite and over simplified stuff) they are given, has just not been thought through properly. I could point to dozens of posts which show how a poor syllabus has harmed the progress of high flyers.
Dadface said:AlephZero said:I can't be bothered to read what the AQA says this week (and they will probably say something different next week), but as sophiecentaur said, the bald statement "Sound waves are longitudina" will satisfy the kid with no interest in science who wants to scrape a C grade (and it will also satisfy teachers with the same objectives!) - but if a bright kid actually plucks a guitar string (or even twangs a ruler on a desk) and observes what happens, he or she is likely to get confused![/QUOTE
Where are you getting this information from? In AS specs kids study SHM and waves in strings in considerable detail.They know that both transverse as well as longitudinal vibrations of the string the ruler, or whatever it is sets up longitudinal waves in the surroundings which, depending on the frequency, can be detected as sound. I rarely see anyone get confused by that. Have you actually met any teachers who have the objectives you alluded to?
Well, if he hasn't, i certainly have. Plenty of teachers enter secondary Science education with nothing more than a GCSE Double award C grade in Physics and Chemistry plus, perhaps a degree in Biology. They are delighted at every student who gets C and above and very often, wouldn't spot a potential First Class Hons in Physics because they just don't know enough. It's not their fault; it's the system and they need a job. I never met one of them who actually wanted to be delivering Physics.
At AS, quite recently, kids were hit, first of all, with Fundamental Particles - involving the classification of particles in terms of Quarks. This was before they even knew the definition of Momentum or what an electron Volt was. A shameless bit of 'bums on seats' if ever there was one. Can you justify that?
Dadface said:"Sound waves are longitudinal" (P1.5.1b AQA physics)
Dadface said:I think it's well understood by all here that ultrasound is sound and we could go for more detailed definitions such as defining "sounds which are audible to humans" or to bats or to any other animal species. But I don't want to get involved in semantics but want to see OPs question answered at a suitable level.
I'm assuming that the OP is currently at a level which is equivelent to GCSE or perhaps AS or A level (UK qualifications).If so the specifications require that students should understand that....."Sound waves are longitudinal" (P1.5.1b AQA physics)
Dadface said:I think it's well understood by all here that ultrasound is sound and we could go for more detailed definitions such as defining "sounds which are audible to humans" or to bats or to any other animal species. But I don't want to get involved in semantics but want to see OPs question answered at a suitable level.
I'm assuming that the OP is currently at a level which is equivelent to GCSE or perhaps AS or A level (UK qualifications).If so the specifications require that students should understand that....."Sound waves are longitudinal" (P1.5.1b AQA physics)