Do Sound Waves Have Gravitational Force?

  • Context: Undergrad 
  • Thread starter Thread starter matpec
  • Start date Start date
  • Tags Tags
    Gravity Sound
Click For Summary

Discussion Overview

The discussion revolves around whether sound waves possess gravitational force. Participants explore the nature of sound, its relationship with energy and mass, and the implications of these relationships on gravitational effects. The conversation includes theoretical considerations and conceptual clarifications.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that sound is merely a disturbance of molecules and does not inherently possess gravitational force.
  • Others argue that since sound involves the movement of mass (air molecules), it could influence the gravitational field.
  • A participant suggests that energy is required to create sound, which may imply a gravitational force associated with that energy.
  • Some participants discuss the relationship between sound frequency and energy, referencing equations like E=hf and E=mc², but express confusion about their implications for mass and gravity.
  • One participant points out that the frequency of sound waves differs from the frequency associated with photons, indicating a common misconception.
  • Another participant outlines a reasoning process suggesting that sound waves increase the energy and thus the mass of air molecules, potentially leading to an increase in gravitational effects.
  • A later reply humorously questions the relevance of the original question, likening it to a whimsical notion, indicating a level of skepticism about the inquiry's seriousness.

Areas of Agreement / Disagreement

Participants express differing views on whether sound waves can be said to have gravitational force, with no consensus reached. Some maintain that sound itself does not have gravity, while others suggest that the energy associated with sound could lead to gravitational effects.

Contextual Notes

There are unresolved questions regarding the definitions of sound, energy, and their relationships to mass and gravity. Participants reference various equations and concepts, but there is no clear agreement on their interpretations or implications.

matpec
Messages
7
Reaction score
0
I come to these forums asking for help as I have searched up and down google without any success on finding an answer to this question and I frankly lack the knowledge to figure this out on my own...

but do sound waves have gravitational force?
 
Physics news on Phys.org
Not necesarrily. when you think of what sound is, it is just vibrating molecules. A disturbance of molecules. Energy, on the other hand, does have a gravitational force. Hope that helps! If you need anymore clarification just ask, I am sure i could help out more.
 
I would imagine that to cause a disturbance within molecules that energy would be required ... making that disturbance have some sort of a gravitational force?
 
well yes in a way. but the disturbance at the smallest part is molecules pushing against each other. therefore sound is primarily molecules pushing against each other. Therefore the molecules and the energy in the molecules has gravity, but not sound itself. Its hard to comprehend, this is a good question!
 
Air consists of molecules. Each molecule has a mass. Mass attracts other masses and that attraction is what we call gravity. Sound is a disturbance of the positions of the air molecules - so it is a disturbance in the positions of mass - so it will cause a change in the gravitational field.
 
in a sense like two tall building next to each other and a wind current flowing through the center?

should the molecules that compose sound be ignored, then is sound just a frequency?
 
yes that's exactly is. sound is not matter nor energy. sound is an interaction. therefore it wouldn't have gravity. Does this clear things up for you at all?
 
unfortunately yes :\
 
but wait ... I just did a lil more reading and found that since E=hf and E=mc^2 then hf=mc^2

so a frequency would indeed have a mass or am I misunderstanding something here
 
  • #10
i think the E in that equation is different. I just looked up the definition of sound in my dictionary of physics. it gave this equation, c^2= E/p where E= mediums relevant elastic constant, and P being density of the medium. C is the speed of sound. so there maybe a mix up of variables. however, i can ask my physics teacher tomorrow. This is really one to make you think.
 
  • #12
the frequency that talks about is the wavelength of a particular photon. the frequency of that wave, not a sound wave. common misconception.
 
  • #13
aaahh damn it ... I got my hopes up for a slight moment

/facepalm
 
  • #14
hahaha its ok! that's what physics is all about really. It was a good idea and you seemed to give it a good, intellectual approach. It sure seemed like it for a second.
 
  • #15
matpec said:
but wait ... I just did a lil more reading and found that since E=hf and E=mc^2 then hf=mc^2

so a frequency would indeed have a mass or am I misunderstanding something here

Yes, you are misunderstanding something. But you also have a good idea. The frequency in the above formula is (very, very roughly) a vibration of the internal state of one molecule, whereas the frequency of the sound wave involves the displacement of many, many molecules. So our "internal frequency" and the "sound frequency" are not related, except through many intermediate steps (involving many other sorts of frequencies also, but let's avoid those).

Let me sketch out the intermediate steps.
1a) By the formula you quoted, the "internal state" frequency is related to the energy of the molecule.
1b) By E=mc2, we know that energy has mass.
2) Because a sound wave increases the energy of the air molecules, it also increases the mass of the air molecules.
3) Since the mass of the air molecules has increased, the gravity it causes will increase. So in this sense, a sound wave has gravity.

Note that we actually did not need statement 1a to reach statement 3. We could have just started from 1b (E=mc2). We currently have a good theory of how to get from 1b to 3. We do not have a good theory of how to get from 1a to 3, and it is an area of active research.
 
  • #16
sorry to p00p on this, but isn't the question sort of like "Mommy, do kitten-fairy souls go to heaven when they die?"

at least that's what it seems like to me.
 

Similar threads

Undergrad Does two-slit sound-wave interference pattern return to original form?
  • · Replies 10 ·
Replies
10
Views
2K
High School What sound frequencies can pass through a hole in a wall?
  • · Replies 31 ·
2
Replies
31
Views
5K
Undergrad Sound pressure and inverse distance law
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Relationship between frequency and power for sound?
  • · Replies 11 ·
Replies
11
Views
6K
Undergrad How fast does a blastwave travel?
  • · Replies 236 ·
8
Replies
236
Views
17K
Undergrad Amplitudes of longitudinal sound waves
  • · Replies 8 ·
Replies
8
Views
4K
High School How's it possible to push on systems with 2 parts? (Newton's third law)
  • · Replies 14 ·
Replies
14
Views
1K
Graduate Exactly how do pressure waves work at the molecular level?
  • · Replies 49 ·
2
Replies
49
Views
5K
Undergrad Speed of Sound in Different Mediums
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Sound power, amplitude, frequency, and decibels
  • · Replies 5 ·
Replies
5
Views
2K