Pentcho Valev
2017-03-23 12:10:29 UTC
Consider a constant-charge parallel-plate capacitor with a polarized SOLID dielectric between the plates:
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Since the molecules of the dielectric material are polarized, they generate an electric field which counteracts the original field and so reduces the voltage between the plates. On the other hand, the attraction between the plates increases (the polarization obviously reinforces the original attraction).
If the dielectric is LIQUID and the plates are totally immersed in it, the attraction between the plates surprisingly decreases, due to a pressure that emerges in the space between the plates:
http://farside.ph.utexas.edu/teaching/jk1/lectures/node46.html
"However, in experiments in which a capacitor is submerged in a dielectric liquid the force per unit area exerted by one plate on another is observed to decrease... [...] This apparent paradox can be explained by taking into account the difference in liquid pressure in the field filled space between the plates and the field free region outside the capacitor."
We have a high pressure between the plates and a lower pressure outside the capacitor so if we punch a small hole in one of the plates, there will be an ETERNAL FLOW through the hole, from inside (between the plates) to outside. In other words, we will have a SYSTEM IN DYNAMIC EQUILIBRIUM. The eternal flow can be harnessed to do work, in violation of the second law of thermodynamics.
The system can violate the second law in a more traditional way. If the plates of the capacitor are only partially immersed, the pressure between them pushes the liquid upwards:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.205.5763&rep=rep1&type=pdf
I. BREVIK, EXPERIMENTS IN PHENOMENOLOGICAL ELECTRODYNAMICS AND THE ELECTROMAGNETIC ENERGY-MOMENTUM TENSOR, pp. 143-144: "We shall first give some supplementary comments on the well known situation shown in fig. 1, where two parallel condenser plates are partially immersed in a dielectric liquid. When a horizontal electric field E is applied between the plates, the liquid will rise within the condenser to some equilibrium height h."
http://www.academia.edu/25650739/Fluids_in_electric_and_magnetic_fields_Pressure_variation_and_stability
I. Brevik, Fluids in electric and magnetic fields: Pressure variation and stability, Can. J . Phys. (1982): "Fig. 1. Two charged condenser plates partly immersed in a dielectric liquid. [...] Fig. 2. The hydrostatic pressure variation from point 1 to point 5 in Fig. 1."
Rise in Liquid Level Between Plates of a Capacitor
Liquid Dielectric Capacitor
Chapter 11.6.2: Force on a liquid dielectric
But the rising dielectric liquid can do useful work, e.g. by lifting some floating weight, and the crucial question is: At the expense of what energy is the work done? Since, by switching the field on and off, we do no work on the system, the energy supplier can only be the ambient heat. That is, the system can cyclically lift floating weights at the expense of heat absorbed from the surroundings, in violation of the second law of thermodynamics.
Let me try to explain the molecular mechanism behind the effect. When two opposite charges (or capacitor plates) are immersed in a dielectric liquid, e.g. water, some additional pressure emerges between them, pushes them apart and so counteracts their electrostatic attraction. If the plates are vertical and only partially immersed, the pressure forces the liquid between the plates to rise above the surface of the pool:
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If it were not for the indicated (with an arrow) dipole, other dipoles in the picture are perfectly polarized as if there were no thermal motion. Of course, this is an oversimplification – thermal motion is a factor which constantly disturbs the polarization order. However the crucial point is that, as can be inferred from the picture, any thermal disturbance contributes to the creation of a pressure between the plates. Consider the indicated dipole. It has just received a strong thermal stroke and undergone rotation. As a result, it pushes adjacent dipoles electrostatically, towards the plates. Macroscopically, the sum of all such disturbances is expressed as a pressure exerted on the plates. One can also say, somewhat roughly, that the indicated dipole has absorbed heat and now, by pushing adjacent dipoles, is trying to convert it into work.
In general terms, electric fields manage to channel the chaotic thermal motion into a macroscopically expressed force capable of doing macroscopic work. Here is an amazing illustration:
"The Formation of the Floating Water Bridge including electric breakdowns"
The eternal motion is driven by heat absorbed from the surroundings. This heat eventually returns to the surroundings, due to friction. However the eternal motion can be harnessed - then heat absorbed from the surroundings will be converted into work, in violation of the second law of thermodynamics.
Pentcho Valev
Loading Image...
Since the molecules of the dielectric material are polarized, they generate an electric field which counteracts the original field and so reduces the voltage between the plates. On the other hand, the attraction between the plates increases (the polarization obviously reinforces the original attraction).
If the dielectric is LIQUID and the plates are totally immersed in it, the attraction between the plates surprisingly decreases, due to a pressure that emerges in the space between the plates:
http://farside.ph.utexas.edu/teaching/jk1/lectures/node46.html
"However, in experiments in which a capacitor is submerged in a dielectric liquid the force per unit area exerted by one plate on another is observed to decrease... [...] This apparent paradox can be explained by taking into account the difference in liquid pressure in the field filled space between the plates and the field free region outside the capacitor."
We have a high pressure between the plates and a lower pressure outside the capacitor so if we punch a small hole in one of the plates, there will be an ETERNAL FLOW through the hole, from inside (between the plates) to outside. In other words, we will have a SYSTEM IN DYNAMIC EQUILIBRIUM. The eternal flow can be harnessed to do work, in violation of the second law of thermodynamics.
The system can violate the second law in a more traditional way. If the plates of the capacitor are only partially immersed, the pressure between them pushes the liquid upwards:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.205.5763&rep=rep1&type=pdf
I. BREVIK, EXPERIMENTS IN PHENOMENOLOGICAL ELECTRODYNAMICS AND THE ELECTROMAGNETIC ENERGY-MOMENTUM TENSOR, pp. 143-144: "We shall first give some supplementary comments on the well known situation shown in fig. 1, where two parallel condenser plates are partially immersed in a dielectric liquid. When a horizontal electric field E is applied between the plates, the liquid will rise within the condenser to some equilibrium height h."
http://www.academia.edu/25650739/Fluids_in_electric_and_magnetic_fields_Pressure_variation_and_stability
I. Brevik, Fluids in electric and magnetic fields: Pressure variation and stability, Can. J . Phys. (1982): "Fig. 1. Two charged condenser plates partly immersed in a dielectric liquid. [...] Fig. 2. The hydrostatic pressure variation from point 1 to point 5 in Fig. 1."
Rise in Liquid Level Between Plates of a Capacitor
Liquid Dielectric Capacitor
Chapter 11.6.2: Force on a liquid dielectric
But the rising dielectric liquid can do useful work, e.g. by lifting some floating weight, and the crucial question is: At the expense of what energy is the work done? Since, by switching the field on and off, we do no work on the system, the energy supplier can only be the ambient heat. That is, the system can cyclically lift floating weights at the expense of heat absorbed from the surroundings, in violation of the second law of thermodynamics.
Let me try to explain the molecular mechanism behind the effect. When two opposite charges (or capacitor plates) are immersed in a dielectric liquid, e.g. water, some additional pressure emerges between them, pushes them apart and so counteracts their electrostatic attraction. If the plates are vertical and only partially immersed, the pressure forces the liquid between the plates to rise above the surface of the pool:
Loading Image...
If it were not for the indicated (with an arrow) dipole, other dipoles in the picture are perfectly polarized as if there were no thermal motion. Of course, this is an oversimplification – thermal motion is a factor which constantly disturbs the polarization order. However the crucial point is that, as can be inferred from the picture, any thermal disturbance contributes to the creation of a pressure between the plates. Consider the indicated dipole. It has just received a strong thermal stroke and undergone rotation. As a result, it pushes adjacent dipoles electrostatically, towards the plates. Macroscopically, the sum of all such disturbances is expressed as a pressure exerted on the plates. One can also say, somewhat roughly, that the indicated dipole has absorbed heat and now, by pushing adjacent dipoles, is trying to convert it into work.
In general terms, electric fields manage to channel the chaotic thermal motion into a macroscopically expressed force capable of doing macroscopic work. Here is an amazing illustration:
"The Formation of the Floating Water Bridge including electric breakdowns"
The eternal motion is driven by heat absorbed from the surroundings. This heat eventually returns to the surroundings, due to friction. However the eternal motion can be harnessed - then heat absorbed from the surroundings will be converted into work, in violation of the second law of thermodynamics.
Pentcho Valev