Electric field frequency at room temperature

Click For Summary

Discussion Overview

The discussion revolves around the concept of measuring electric field frequency at room temperature, particularly in relation to air molecules and their interactions with a sensitive voltmeter. Participants explore the feasibility of detecting voltage changes due to molecular collisions and the theoretical implications of such measurements.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Thought experiment

Main Points Raised

  • One participant inquires about the frequency of emf at standard temperature and pressure (STP) when using a nano-sized voltmeter to detect voltage changes from air molecule collisions.
  • Another participant questions whether neutral air molecules, such as oxygen and nitrogen, can produce an electric field or potential by themselves, suggesting that only molecules with dipole moments might have an effect.
  • Some participants mention that while oxygen and nitrogen do not have permanent dipole moments, water vapor does, which could potentially influence the measurements.
  • A participant proposes a thought experiment involving a capacitor and Faraday cage to explore the generation of AC current from ambient air, suggesting that many wires or coils may be needed to produce significant power.
  • Concerns are raised about the feasibility of measuring individual dipoles of gas molecules and whether the proposed setups could yield meaningful results.
  • Another participant expresses skepticism about the ability of neutral molecules to generate an EM field, while also acknowledging the potential influence of dipolar molecules.
  • One participant discusses the kinetic energy of gas molecules and how it could theoretically be converted into electrical power, although they recognize the challenges involved in achieving significant energy output.
  • There are references to the laws of thermodynamics and the implications of attempting to extract energy from a gas's kinetic energy.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of measuring voltage from neutral air molecules and the effectiveness of the proposed experimental setups. There is no consensus on whether the ideas presented could yield significant electrical power or if they violate thermodynamic principles.

Contextual Notes

Participants highlight limitations in measuring individual molecular interactions and the assumptions regarding the behavior of neutral versus dipolar molecules. The discussion also touches on the complexities of converting kinetic energy into electrical power and the potential need for additional components like semiconductors.

elegysix
Messages
404
Reaction score
15
Hello, I am trying to figure out what frequency emf there might be at STP. I mean that like this - Imagine that I have a nano-sized voltmeter with one probe grounded, and it's small/sensitive enough so that as air molecules collide with the other probe, it picks up a voltage. What sort of frequency would that change at? Is there a way to solve for this, or a ball-park figure?

thanks.
 
Physics news on Phys.org
"air molecules"? You mean Oxygen and Nitrogen molecules. Are they charged?
 
yes oxygen and nitrogen molecules, and maybe some Co2 and water vapor too. not necessarily charged. maybe a small portion of them. Like the air in my room, nothing special. I'm sure some of the molecules have dipole moments.
 
Spectral line for oxygen is about 513nm. So frequency about 5.85*10^14 hertz ?
 
CWatters said:
Spectral line for oxygen is about 513nm. So frequency about 5.85*10^14 hertz ?

The spectrum of oxygen undergoing electrical discharge excitation contains at least seventy-three (73) separate emission lines between four thousand (4,000) and seven thousand (7,000) Angstroms.

http://astro.u-strasbg.fr/~koppen/discharge/

If we select only one of those emission lines and take it’s inverse to convert from wavelength to frequency (as above) the result could not be measured by any voltmeter, and seems meaningless.

It appears the OP by elegysix is not easily answered, because measuring individual dipoles of gas molecules is probably impossible.
 
Last edited:
I think I remember something in thermo or chemistry about it, like the average rate of collisions between gas molecules. Would that give me a ball park figure? Anyone know what that might be called?
 
elegysix said:
yes oxygen and nitrogen molecules, and maybe some Co2 and water vapor too. not necessarily charged. maybe a small portion of them. Like the air in my room, nothing special. I'm sure some of the molecules have dipole moments.

Some molecules may have dipole moment.
Oxygen, nitrogen and CO2 don't have permanent (electric) dipole moment.
Water is the only molecule in the above list with a permanent dipole.
What do you actually want to measure or to do?
 
I don't believe your probe would pick up a voltage from neutral particles colliding with it.
 
here is the idea... haven't worked out any numbers yet, so it's just a thought experiment for now. There are two set ups for this thought experiment.

1) take a capacitor (very high C) and bias it in a specific way. have the capacitor placed inside a faraday cage or conductor so there is little or no external E field acting on the system. Connect a lead to one side of the capacitor and let a very small point of the lead be in contact with the air and fields outside the cage. The purpose is to try and have AC current flowing in the wire, even if it is absolutely minuscule.

2) attach many wires to a conductive plate, letting the other ends be separate and unconncected. have that system placed inside a conductor/faraday cage. Only allow the very tips of the unconnected ends to be exposed to the air and fields outside the cage. This way, a small difference in potential between any tips of the wires might cause a very small AC current in the wires and connecting plate.

The purpose is then to wind toroid coils around the wires carrying the small AC current, in hopes to remove some energy from the gases. I expect that this will take many, many hundreds or thousands of wires or coils to produce any significant power, if it is at all possible.
 
Last edited:
  • #10
I have a feeling the OP, and many people who responded to this thread, are all talking about different things, and none of them sinking in.

elegysix: before you invent a device here, can you tell me why you think that a neutral molecule will produce an EM field or a potential by itself? Let's established clearly what the physics involved here first and try to understand the scenario.

Zz.
 
  • #11
elegysix said:
here is the idea... haven't worked out any numbers yet, so it's just a thought experiment for now. There are two set ups for this thought experiment.

1) take a capacitor (very high C) and bias it in a specific way. have the capacitor placed inside a faraday cage or conductor so there is little or no external E field acting on the system. Connect a lead to one side of the capacitor and let a very small point of the lead be in contact with the air and fields outside the cage. The purpose is to try and have AC current flowing in the wire, even if it is absolutely minuscule.

2) attach many wires to a conductive plate, letting the other ends be separate and unconncected. have that system placed inside a conductor/faraday cage. Only allow the very tips of the unconnected ends to be exposed to the air and fields outside the cage. This way, a small difference in potential between any tips of the wires might cause a very small AC current in the wires and connecting plate.

The purpose is then to wind toroid coils around the wires carrying the small AC current, in hopes to remove some energy from the gases. I expect that this will take many, many hundreds or thousands of wires or coils to produce any significant power, if it is at all possible.

elegysix, Thank you for finally, after all the above obfuscation, making clear your proposal!
In my estimation no significant electrical power could be gleaned from such an apparatus.
 
  • #12
ZapperZ said:
can you tell me why you think that a neutral molecule will produce an EM field or a potential by itself?
Zz.

I don't really expect a neutral molecule have much effect on this, if any at all. Hopefully it will, but I too doubt it.

I expect that water vapor molecules or others with a significant dipole will be able to cause an effect, as well as any unbalanced molecules in the area.

I may have a Static E field in the vicinity to attract any unbalanced molecules in the area, to increase the effect. (I may try this)

The idea is that maybe with this, I can turn some of a gases' kinetic energy (heat) into electrical power.

I realize that this is going to be a very small amount of work.

However, there are no moving parts involved, and I can "theoretically" build millions or more of these conductors, which would then draw enough power to be significant. I don't imagine that there would be much cost to keep such a thing operating, it is essentially only wires, and there is no significant power through anyone wire. Make the world cooler by gaining electric power, with almost no upkeep - it's worth at least trying to me.
 
  • #13
I think this violates the laws of thermodynamics, in moving heat from a hot object and giving it to a cold object, for example, if you were to use this device to power a heater in another room.
 
  • #14
elegysix said:
The idea is that maybe with this, I can turn some of a gases' kinetic energy (heat) into electrical power.

I realize that this is going to be a very small amount of work.

However, there are no moving parts involved, and I can "theoretically" build millions or more of these conductors, which would then draw enough power to be significant.

The KE of a gas molecule is approximately equal to 3/2 kT. When you know its mass and the space it occupies you can work out a ballpark frequency.

But as you state, to farm any meaning full amount of energy say from a gas heated by (eg) solar energy you will need millions or more conductors. The frequency of the many small generated currents will all be out of phase and hence will cancel. Therefore you will need to rectify each small ac current into a dc flow. This means for each conductor you will also need a small semiconductor. And this way you are close to the idea of a solar panel.

Full marks for the idea but you’ve been beaten to it a long time ago. Anyway I hope you keep on going, we need people like you.
 
  • #15
MikeyW said:
I think this violates the laws of thermodynamics, in moving heat from a hot object and giving it to a cold object, for example, if you were to use this device to power a heater in another room.

I don't think it violates them, it isn't violating conservation of energy either. Rather, the moving molecules with an electric field should induce a small AC current in the conductor, essentially slowing down the molecules while providing a current. It is just transforming energy. Like the opposite of a fan.
 
  • #16
Per Oni said:
Full marks for the idea but you’ve been beaten to it a long time ago.

Who/what was made like this before? I think this is somewhat different from a solar panel. Did someone else already try this?

thanks
 
  • #17
elegysix said:
Who/what was made like this before? I think this is somewhat different from a solar panel. Did someone else already try this?
thanks

Not exactly like you propsed. Here are some sites you might be interested into start:
http://www.espressomilkcooler.com/how_thermoelectric_generators_work.htm
http://www.tegpower.com/
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 42 ·
2
Replies
42
Views
4K
Replies
92
Views
8K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 13 ·
Replies
13
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 9 ·
Replies
9
Views
7K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 9 ·
Replies
9
Views
5K