Volcanoes & Perpetual Motion

Discussion in 'Pseudoscience' started by Layman, Jul 2, 2014.

  1. Layman Totally Internally Reflected Valued Senior Member

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    One major flaw most perpetual motion devices have is that they try to take energy from the force of gravity and then expect no forces of friction or a transfer of energy, so they are unable to bring parts of the device to an equal elevation as when they started. Then take a volcano for instance, dust and debris from a volcano can reach an elevation that is higher than where it started at. Then how is that possible? Well, volcanoes erupt from an increase and release of heat and pressure created from Earths gravity. The gravitation pull of the layers of rock sitting on top of each other will always be a constant pull that will always create more heat and pressure. This heat and pressure should then never go away. Therefore, volcanoes will continue to erupt indefinitely into the future. It is nothing that will ever stop. The core of the Earth will always remain hot. Then there should be a never ending cycle of volcano eruptions on Earth. Then why hasn't this ever been seen as an example of perpetual motion in nature?
     
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  3. exchemist Valued Senior Member

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    Because it is not, any more than the wind is.

    The energy source of vulcanism is the interior heat of the Earth, but this comes from radioactive decay, which is a finite energy supply. The energy source of winds is solar heat, which is similarly a finite source of energy.

    Both are very large and long-lived energy sources by the standards of human beings, but the physical scale and timescale of stellar and planetary phenomena almost always are.
     
    Last edited: Jul 2, 2014
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  5. origin In a democracy you deserve the leaders you elect. Valued Senior Member

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    The one major flaw in perpetual motion is that it is not possible.

    You do not understand what perpetual motion is.

    If I have a waterwheel it will run a mill with zero energy input except for the water flow, which is of course due to gravity -this is not perpetual motion.

    A perpetual motion machine is a device that when you start it, it will continue to run with no additional energy input. A volcano has continuous energy input from the heat of the earth, the watewheel has energy input from the stream, so these are not perpetual motion.
     
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  7. Layman Totally Internally Reflected Valued Senior Member

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    The interior heat of the Earth does not come from radioactive decay. Do you even know what radioactive decay even is? Solar radiation will eventually end when a star burns out. Although, the star will continue to always have internal pressure that will cause heat. It would just be questionable if the heat from that alone would heat up the planet. If the Earth was flung out of orbit of the sun, it could still have volcanoes, and this could happen when Andromeda Galaxy collides with the Milky Way.
     
  8. Layman Totally Internally Reflected Valued Senior Member

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    According to Newtons Laws, any body in motion will remain in motion until acted on by another force.


    Are you trying to insult my intelligence again? Of course I know what perpetual motion is.
    I am sorry that watermills do not run on "zero energy" as you put it. Do you even know what energy is?
    Gravity is not supposed to be able to be considered a form of energy that could be added to the system. I think it actually is perpetual motion, because a volcanoes is able to take energy from the force of gravity. That is where the energy from the heat of the Earth comes from. All that is required for perpetual motion is that it is a system that remains in motion that never ends. The photon itself in deep space has been said to be a perpetual motion machine in some books.
     
  9. Janus58 Valued Senior Member

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    Internal pressure by itself even if due to gravity, doe not create heat. To create heat, the body in motion has to compress further under that pressure. ( the Earth would have to shrink in size).

    The Earth's internal heat is the product of three things: Earlier compression of the Earth during it's formation. Impacts from extraterrestrial bodies, and yes, the decay of radioactive isotopes. Much of the heat from the Earth's formation remains because rock is a poor conductor of heat. Once the crust formed, it slowed down the loss of heat. Radioactive decay also replaces some of that lost heat.

    This will not continue forever. The Earth's internal heat was hotter in the past and will will be cooler in the future. It will eventually become geologically inactive.
     
  10. billvon Valued Senior Member

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    Actually that is one of the sources. It is slowly cooling and thus will not be "perpetual." Eventually we will end up like Mars, with a solid core.

    Pressure does not cause heat. It can cause a rise in temperature. Temperature does not equal heat.

    Sure, if you add energy back to the planet after it solidifies. A collision with another solar system (and a change in orbital dynamics) could do that.
    No, they take energy from the differential between the core of the Earth and the surface. As that differential decreases with time volcanoes will slow down and stop.
     
  11. KitemanSA Registered Senior Member

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    No. Volcanos are driven by the radioactive decay heat at the core of the earth. That decay heat comes from 4 significant sources; U238, U235, Th232, & K40.
     
  12. Layman Totally Internally Reflected Valued Senior Member

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    How do you know that the Earth hasn't decreased from it's original size already? To me, the idea that a high amount of gravitational pressure does not create heat is just absurd. It is a well known fact that an increase in temperature will be found with an increase of of pressure. I get the feeling that your just assuming that, because it has been tied to perpetual motion in this case. That doesn't justify doing away with that concept in itself.
    If radioactive decay was solely responsible for the temperature of Earths core, then it wouldn't be that much hotter than the surface...
    It has already been almost forever that volcanoes have been active on Earth, roughly 4.5 billion years.
     
  13. Janus58 Valued Senior Member

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    The key word phrase here is "with an increase of pressure". If you increase the pressure on a substance, it will heat up, but once the pressure becomes constant, no more heat is generated, and what heat there is will radiate away over time. A constant pressure will not keep creating new heat.
    I never said that it was solely responsible. Again, much of the Earth's internal heat is left over from its formation. As such, most of the heat would be generated at the center. As objects cool, they cool from the outside in, so we expect the core to be the hottest. Radioactive decay slows the cooling.
    4.5 billion year on the cosmic scale is nowhere near "almost forever". The Earth has been geologically active for as long as it has mainly due to its size. Larger objects have smaller surface area to volume ratios. Since surface area controls how fast the object can radiate way heat, larger planets cool slower. Also, in its earlier years, the radioisotope concentration was higher. As time goes on the earth will continue to cool from the outside in, the crust will become thicker, there will be fewer and fewer points where magma can push through to the surface and there will be fewer and fewer volcanoes, until one day, there will be none. It will be a long time, but it will not be forever or even nearly forever.
     
  14. cosmictraveler Be kind to yourself always. Valued Senior Member

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  15. origin In a democracy you deserve the leaders you elect. Valued Senior Member

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    correct.

    Again? No.

    It did not seem so.

    I never said that.

    Yes.

    Really? Why did you make up that rule?
    By the way gravity is not energy. Do you even know what energy is?

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    So if you ignore this force or that energy then something can look like a perpetual motion device - that is sort of silly isn't it?
     
  16. TBodillia Registered Senior Member

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    http://physicsworld.com/cws/article...active-decay-accounts-for-half-of-earths-heat

    "About 50% of the heat given off by the Earth is generated by the radioactive decay of elements such as uranium and thorium, and their decay products."

    Mars doesn't have any active volcanoes, neither does Venus (as far as we know). Earth's volcanoes are mainly at the boundaries of the tectonic plates. Mantle plumes account for some too.
     
  17. billvon Valued Senior Member

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    Then a bit more study of physics might be in order. The ideal gas law would be a good place to start.
    Again, once you understand the ideal gas law this will all become clearer. You can compress a gas and it will heat up. That requires work. Once you stop doing work, and just maintain the pressure that is already there, no new energy is added. Again heat does not equal temperature.

    What that means is that if you compress the core of the Earth with gravitational force, you can add heat energy ONCE. That happened several billion years ago. It is not happening now.
    Yes, and they have been gradually decreasing in intensity as both the heat of formation and the heat of radioactive decay drops off.
     
  18. Layman Totally Internally Reflected Valued Senior Member

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    I didn't make up that rule. That is the rule that I heard against perpetual motion and why perpetual motion devices are not possible. I am surprised you never heard that one being that your so incredibly old. You should tell that to Alan Guth, and that disproves his inflation theory. He seems to think that the energy of gravity can be transferred from the expansion of the universe for some unknown reason. I don't think science has even been able to take the first baby steps in order to explain how that could be possible. If gravity is not considered a source of energy, then one could never explain how it ever transferred that energy to anything!

    I don't see your point here. Gravity is considered a force, but like you said, "By the way gravity is not energy". If the force of gravity could be converted to energy, then I think a perpetual motion device would work as long as it is converted to heat and then that heat is converted to kinetic energy. As far as I know, there are no attempts at building perpetual motion devices in this fashion. Most of them try to transfer the force of gravity into kinetic energy and just lose kinetic energy to heat.
     
  19. Layman Totally Internally Reflected Valued Senior Member

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    The force of gravity will always continue to pull down and apply pressure to the surface it is sitting on. I see how this would be no different than mechanical pressure being continued to be applied to a surface. It would require work to do that.

    I think you could use a study in geology. For instance Old Faithful is as regular as ever. Then volcanic activity happens at a normal consistent cycle.
     
  20. Layman Totally Internally Reflected Valued Senior Member

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    Then no material will achieve escape velocity of the Earth, and the core of the Earth will remain under the same amount of pressure. Therefore, the core will remain at the same constant temperature. It will stay at the same temperature that is generated from a certain amount of pressure.
    You do realize that is a bit over a fourth of the lifetime of the universe, right? There has been no evidence that the core of the Earth is cooling, or that the activity of volcanoes has been slowing down in pace. It happens almost like clockwork.
     
  21. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Old Faithful, named by members of the 1870 Washburn Expedition, was once called “Eternity’s Timepiece” because of the regularity of its eruptions. However, despite the myth, this geyser has never erupted at exact hourly intervals, nor is it the largest or most regular geyser in Yellowstone. However, it does erupt more frequently than any other of the large geysers.

    https://www.google.com/url?sa=t&rct...uYDQDQ&usg=AFQjCNEHj1poZCXOlgoL4mEeedDeCSJ00A
     
  22. Layman Totally Internally Reflected Valued Senior Member

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    That may be true, but geological records have shown that volcanoes erupt at regular intervals. They can know this from the sediment layers and are able to date when previous eruptions occurred. Then they can set a time frame when a volcano is expected to erupt again.
     
  23. cosmictraveler Be kind to yourself always. Valued Senior Member

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    I visited there and had to wait over 1 hour before it erupted then I waited again over 1.5 hours before it erupted once more. That shows the statement I posted was correct that the geyser does not erupt on a regular basis but when it wants to. They have a snack/souvenir store about a quarter of a mile away for the geyser and do a good deal of business which makes me believe they somehow have a valve which turns the geyser on and off.

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