Volcanoes & Perpetual Motion

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

  1. wellwisher Banned Banned

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    The earth's gravity creates pressure, with the highest pressure in the core. This creates a perpetual pressure gradient between the core and the surface. In weather, if we have high and low pressure systems, there is movement of air between them.

    If higher pressure moves toward lower pressure; volcano, this reduces the pressure gradient. But since gravity continues to act, it squashes the matter restoring the pressure gradient for another cycle.

    The problem with this perpetual motion scenario, is gravity creates a downward force that will point in the opposite direction of the force that is pushing from high to low pressure. These will cancel. We can't place a hose between the top and bottom of a lake and use the pressure on the bottom to pump water into the air, because gravity cancels this upward force.

    There is a work-around. This can be done using materials of various densities. The light materials will try to float upward as the heavies sink. With water and oil, for example, the lighter oil will follow the pressure gradient upward, while water will follow the gravity gradient downward. These balance out.

    Another way to do this is with heat since most materials get less dense when heated and more dense when they cool. The hotter lighter materials will follow the pressure gradient while the cooler denser materials will follow gravity and sink, with a balanced forming based on heating and cooling.

    Radioactive decay combines both of these to make heat and make small less dense atoms from heavier atoms.
     
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  3. origin Heading towards oblivion Valued Senior Member

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    Well my young fellow, I have not heard of this because it is not true. This is apparently one of your many misunderstanding that with some luck you will out grow. As a matter of fact many people have tried to contruct perpetual motion machines using only gravity, which all fail of course. The problem is you still are showing that you do not know what a perpetual motion machine is. I have told you what they are.

    So you do not understand cosmic inflation either.

    You are correct that the force of gravity can yield energy such as gravitational PE. If you draw heat from the earth such as geothermal electrical energy, that is not a perpetual motion device any more than a hydroelectical dam is a perpetual motion device. As you remove heat from the earth it will cool unless more energy is put into the earth to create more heat. Elementary thermodynamics. Gravity does not make heat. Pressure does not make heat. An INCREASE in pressure over time WILL produce heat.


    All real scientific attempts at perpetual motion machines ended almost 200 years ago when the laws of thermodynamics were discovered. Using the heat reservoir of the earth cannnot yield an example of a perpetual motion machine.

    Read what a perpetual motion machine actually is to see why!

    The key is a true perpetual motion machine must be an isolated system. Hopefully the subtleties are not beyond your grasp
     
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  5. krash661 [MK6] transitioning scifi to reality Valued Senior Member

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    exactly what you attempted before even reading origin's post huh.
     
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  7. krash661 [MK6] transitioning scifi to reality Valued Senior Member

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    raise temperature: to become or make something warm or hot


    tem·per·a·ture
    1. degree of heat: the degree of heat as an inherent quality of objects expressed as hotness or coldness relative to something else

    rise
    1. increase: an increase in amount
    3.get higher: to gain a greater height or level
    4.grow larger: to increase in amount,
    5. upward slope: an upward slope or gradient
    7. upward movement: an ascent or
    8. intensification: an increase in degree, intensity, or force

    heat
    1. energy perceived as temperature: a form of transferred energy that arises from the random motion of molecules and is felt as temperature, especially as warmth or hotness.
    Heat is transmitted by conduction, convection, or radiation
    2. degree of hotness: the perceptible or measurable degree of hotness
    3. source of higher temperature: a source of warmth,

    " temperature is a numerical measure of hot and cold.
    its measurement is by detection of heat radiation
    Many things depend on temperature, such as
    physical properties of materials including the phase (solid, liquid, gaseous or plasma), density, solubility, vapor pressure, electrical conductivity"

    " Clean fresh water boils at about 100 °C (212 °F) at earth's standard atmospheric pressure. The boiling point is the temperature at which the vapor pressure is equal to the atmospheric pressure around the water. "
     
  8. sideshowbob Sorry, wrong number. Valued Senior Member

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    7,057
    The obstacle to perpetual motion is the Second Law of Thermodynamics: You can't get something for nothing; you can't even break even.

    All of the energy in the universe is spreading out. There are local exceptions but the general rule is that the concentration of energy decreases toward equilibrium. That equilibrium is called the "heat death" of the universe: When all of the energy is spread out evenly, nothing can move.

    So... the core of the Earth is cooling, like everything else, even if it hasn't been measured in the very short time us humans have been here.

    Of course, the energy released by volcanoes will be available as long as humans exist, which is as good as perpetually. But the obstacle to using volcanoes, per se, as a source of energy is that they're too bloody unreliable; they're as likely to incinerate your house as to keep it warm.

    People do use geothermic energy to heat their houses, which is free (except for the infrastructure) but not literally perpetual.
     
  9. exchemist Valued Senior Member

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    This is not my understanding. What evidence do you have for the supposed regularity of volcanic eruptions?
     
  10. billvon Valued Senior Member

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    No, it requires zero work to apply a pressure to a surface. I can do that by putting a weight on the floor and leaving it there. Once placed, the weight does no work.
    Old Faithful has been gradually slowing down even in the tiny time span we have been watching it. Over geologic time all such activity will slow down and stop.
     
  11. Motor Daddy Valued Senior Member

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    The work is rotational work. The earth is forcing the object to rotate at a distance greater than zero away from the axis. That is rotational work, just like a load on a crankshaft while it is spinning at a constant RPM. There is force and rotation, and that is work.
     
  12. exchemist Valued Senior Member

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    Utter balls. Naturally.
     
  13. Motor Daddy Valued Senior Member

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    Really? Care to enlighten me about gravity and rotational work?
     
  14. exchemist Valued Senior Member

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    No.
     
  15. Motor Daddy Valued Senior Member

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    Then keep your BS to yourself.
     
  16. exchemist Valued Senior Member

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    The point is that it is not gravity that powers vulcanism, it is heat. Heat causes circulation of rocks in the Earth and in some places the temperature is high enough compared with the pressure and the melting points of the minerals for partial melting to occur. These are called zones of partial melting: http://en.wikipedia.org/wiki/Partial_melting

    The molten rock, being less dense and being able to flow through cracks, rises and as it does so dissolved gases start to come out of solution, further reducing the mean density and accelerating the rate of rise. As the mixture approaches the surface, the pressurised gas becomes a potent explosive force (because gas expands greatly as the pressure reduces).

    But the whole process is due to heat: without the high temperature there would be no circulation, there would be no spots where partial melting could take place and the rest of the process could not occur. Gravity is not the driver. Heat is.
     
  17. billvon Valued Senior Member

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    So if you allow a flywheel to spin freely in a vacuum, it does work?
     
  18. Motor Daddy Valued Senior Member

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    Gravity is not what you think. It is not an attraction, it is something way way different than you think.

    You are standing on earth in one spot. The earth is rotating. While the earth is rotating you bend down and lift a rock.

    Can you describe what just happened, from a "god's eye" view of the path that rock took in space as it was lifted and the earth rotated?

    Think about that as you lifted the rock, the distance between the rock and the center of the earth was increasing, causing the path to become larger and further away. When you hold the rock up in the air you are forcing the rock to rotate at a greater distance per time than it was being forced by the earth at rest while it was on the ground making a lesser path in space per time.

    When you lift the rock you cause the distance per time to increase, and that is an acceleration. When you remove the force (let go), there is less force, so the rock has to "decelerate" and the only way it can do that is to get closer to the axis, ie fall!
     
  19. Motor Daddy Valued Senior Member

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    No force means no work, just RPM.
     
  20. billvon Valued Senior Member

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    Oh, there's plenty of force inside a flywheel! Which is why they sometimes come apart with very . . . dramatic results.
     
  21. Motor Daddy Valued Senior Member

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    How much work is it doing while it's spinning in a vacuum?

    How much force is being applied to a flywheel that has no force being applied to it??? :bugeye:
     
  22. billvon Valued Senior Member

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    While it is spinning freely? Zero.
     
  23. Motor Daddy Valued Senior Member

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    Okay then, no force means no work. Do you know what work is?
     

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