# classification of waves

#### elftown

##### Full Member
10+ Year Member
could someone classify all the waves we need to know for me please? i can't seem to get them in my head without a coherent cumulative list/table of them.

and perhaps a take home point on each

#### inaccensa

##### Full Member
10+ Year Member
could someone classify all the waves we need to know for me please? i can't seem to get them in my head without a coherent cumulative list/table of them.

and perhaps a take home point on each

waves can be classified into transverse and longitudinal waves

Electromagnetic waves are Transverse waves Ex- Light, waves on string

Longitudinal/ compressional waves- Ex -sound waves aka mechnical waves or pressure waves

#### SuperSaiyan3

##### Full Member
7+ Year Member
waves can be classified into transverse and longitudinal waves

Electromagnetic waves are Transverse waves Ex- Light, waves on string

Longitudinal/ compressional waves- Ex -sound waves aka mechnical waves or pressure waves

That's about the gist of it. Your explanation was good but it kind of confused me so I'll try to break it down into something easily memorizable.

"LONG PANTS": longitudinal waves are PArallel in displacement. I say PA because of the PANTS. These waves are for the SOUNDWAVES or pressure waves as indicated by inaccensa. They are compressional. I like to memorize sound as long because sound actually gets somewhere.

"TRANS PERP": transverse waves have perpendicular displacement.

They are electromagnetic waves and water waves and waves on a string, as noted. They don't actually travel anywhere. They do propagate energy however.

Does anybody know if LONG PANTS waves also ONLY transmit energy and do not mediate matter movement? I don't think it does...

SS3

#### inaccensa

##### Full Member
10+ Year Member
That's about the gist of it. Your explanation was good but it kind of confused me so I'll try to break it down into something easily memorizable.

"LONG PANTS": longitudinal waves are PArallel in displacement. I say PA because of the PANTS. These waves are for the SOUNDWAVES or pressure waves as indicated by inaccensa. They are compressional. I like to memorize sound as long because sound actually gets somewhere.

"TRANS PERP": transverse waves have perpendicular displacement.

They are electromagnetic waves and water waves and waves on a string, as noted. They don't actually travel anywhere. They do propagate energy however.

Does anybody know if LONG PANTS waves also ONLY transmit energy and do not mediate matter movement? I don't think it does...

SS3

i think sound waves will mediate matter movement. This is what I think
Since sound wave is a pressure wave. Increase the pressure, you increase the density of the medium, so shouldn't it cause matter around it to move?

For electromagnetic waves, as someone else had explained that they only propogate energy. I had asked how EM waves propogate through vacuum since there is no matter. The reply was that they only propagate energy.

I'm confused

#### SuperSaiyan3

##### Full Member
7+ Year Member
i think sound waves will mediate matter movement. This is what I think
Since sound wave is a pressure wave. Increase the pressure, you increase the density of the medium, so shouldn't it cause matter around it to move?

For electromagnetic waves, as someone else had explained that they only propogate energy. I had asked how EM waves propogate through vacuum since there is no matter. The reply was that they only propagate energy.

I'm confused

Somebody's gonna have to double check on that claim that soundwaves will mediate matter movement because that sure is FISHY.

But ya. EM waves propagate energy only. Not sure why exactly, but I do know that radiation is the form of energy transfer that does not require a medium (the only thing that can transfer energy in a VACUUM). That is sort of proof for why it isn't... but if you want to look into it furhter, be my guest.

EDIT:::

I just looked into it and turns out ALL kinds of mechanical waves (sound, light, water waves, watever)
they ALL only propagate ENERGY, not matter.

Quote from Kaplan:
- mechanical waves (e.g., water, sound, etc.)
- Mechanical waves cause a local oscillation of material. In the case of a transverse wave on water, the material that makes up the wave (the water particles) oscillates up and down. No material is transported as a result of mechanical waves
- waves cause a propagation of energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy.
- mechanical wave, such as sound, where the wave is made up of the vibrations of atoms in air. While energy is propagated by a sound wave, the air particles themselves are not. On the other hand, in an electromagnetic wave, such as light, photons are transported across a medium along with the energy of the wave.
NOTE: PHOTONS are not MATTER. They are entities of energy.

Hope that helped.

Last edited:

#### inaccensa

##### Full Member
10+ Year Member
Somebody's gonna have to double check on that claim that soundwaves will mediate matter movement because that sure is FISHY.

But ya. EM waves propagate energy only. Not sure why exactly, but I do know that radiation is the form of energy transfer that does not require a medium (the only thing that can transfer energy in a VACUUM). That is sort of proof for why it isn't... but if you want to look into it furhter, be my guest.

EDIT:::

I just looked into it and turns out ALL kinds of mechanical waves (sound, light, water waves, watever)
they ALL only propagate ENERGY, not matter.

Quote from Kaplan:
- mechanical waves (e.g., water, sound, etc.)
- Mechanical waves cause a local oscillation of material. In the case of a transverse wave on water, the material that makes up the wave (the water particles) oscillates up and down. No material is transported as a result of mechanical waves
- waves cause a propagation of energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy.
- mechanical wave, such as sound, where the wave is made up of the vibrations of atoms in air. While energy is propagated by a sound wave, the air particles themselves are not. On the other hand, in an electromagnetic wave, such as light, photons are transported across a medium along with the energy of the wave.
NOTE: PHOTONS are not MATTER. They are entities of energy.

Hope that helped.

So the moral is that all Waves propagate Energy and not matter.

That makes sense, but let me ask you this
Since the waves propagate energy and momentum. Then this implies that the mass part of the equation is constant.

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