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Thread: Gain Energy from any temperature?

  1. #1 Gain Energy from any temperature? 
    Forum Sophomore confusedasyou's Avatar
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    So I started learning more about how gas and water behave when hot and cold temperatures are introduced to them . I learned that when gas or liquid is heated up, the particles move faster and spread further apart. When they are cooled they move slower and get closer together. I know that temperature is always around. No matter where you go. So is there a way to collect the energy created from the movement of these particles? I mean if the particles are force outward, when they get hot, then that force should be able to be used to benefit the human race right? The same with the force of the particles closing in when they get cold. I love learning about science. I also think it is cool how water is purified during its evaporation process. Just learned about that. Sadly I am 25 but at least I am learning right? As usual please leave your constructive criticism and logical answers below. Thanks in advance.


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    KJW
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    The question you ask is the essence of the second law of thermodynamics as it was originally formulated. The answer is no, you cannot extract work energy from a single temperature source. You must have a temperature difference in order to extract work from thermal energy.


    There are no paradoxes in relativity, just people's misunderstandings of it.
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    Quote Originally Posted by confusedasyou View Post
    So is there a way to collect the energy created from the movement of these particles?
    Any thermodynamic engine does just that. Steam turbines, automobile engines, etc. As mentioned, you do need a temperature difference.
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    Quote Originally Posted by confusedasyou View Post
    So I started learning more about how gas and water behave when hot and cold temperatures are introduced to them . I learned that when gas or liquid is heated up, the particles move faster and spread further apart. When they are cooled they move slower and get closer together. I know that temperature is always around. No matter where you go. So is there a way to collect the energy created from the movement of these particles? I mean if the particles are force outward, when they get hot, then that force should be able to be used to benefit the human race right? The same with the force of the particles closing in when they get cold. I love learning about science. I also think it is cool how water is purified during its evaporation process. Just learned about that. Sadly I am 25 but at least I am learning right? As usual please leave your constructive criticism and logical answers below. Thanks in advance.
    When these particles (=molecules) hit and rebound from the surface of the container enclosing them, the force they exert, over the area of the surface, gives rise to what we call the pressure of the gas. They move faster as the gas is heated, so the pressure goes up, unless the gas is allowed to expand. The principle of a heat engine (e.g. steam, diesel or gasoline engine, or turbine) is that hot gas expands by using the force of this pressure to drive a piston or turbine blades. There are some limits on how much energy you can get out (see the remarks from others about 2nd Law of Thermodynamics) but that is the principle of every heat engine. And it has benefitted the human race considerably, hasn't it?.

    As to the "force" of molecules closing in, it does not quite work like that. So long as there is any movement of the molecules, they will exert a positive pressure. However, if the pressure they exert is less than the background pressure we have all around us (the atmospheric pressure), the atmosphere will tend to push in and squash the gas. This is what give rise to what we commonly think of as "suction": really, it is the atmosphere "pushing" rather than anything "pulling".

    In early steam engines, the power stroke exploited this. The cylinder was filled with steam at only a little above atmospheric pressure (early boilers were cast iron and blew up if you pressurised them much). Then, a spray of cold water was injected into the cylinder, causing the steam to condense rapidly. As the steam had displaced most of the air from the cylinder, when the steam condensed it left a partial vacuum (=pressure well below atmospheric). The resulting "suction" (=really the atmosphere pushing, from the outside, with little to oppose it) caused the piston to move powerfully into the cylinder. As a matter of fact, even in later steam engines, and in steam turbines, there is always a condenser in the exhaust circuit, which removes all the pressure of the steam and thus creates a partial vacuum on the exhaust side of the engine. This adds to the total pressure difference in the engine and hence to its power output.

    So in a way you are also right that the "closing in" of the molecules provides a source of extractable energy.
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    Quote Originally Posted by exchemist View Post
    When these particles (=molecules) hit and rebound from the surface of the container enclosing them, the force they exert, over the area of the surface, gives rise to what we call the pressure of the gas. They move faster as the gas is heated, so the pressure goes up, unless the gas is allowed to expand. The principle of a heat engine (e.g. steam, diesel or gasoline engine, or turbine) is that hot gas expands by using the force of this pressure to drive a piston or turbine blades. There are some limits on how much energy you can get out (see the remarks from others about 2nd Law of Thermodynamics) but that is the principle of every heat engine. And it has benefitted the human race considerably, hasn't it?.

    As to the "force" of molecules closing in, it does not quite work like that. So long as there is any movement of the molecules, they will exert a positive pressure. However, if the pressure they exert is less than the background pressure we have all around us (the atmospheric pressure), the atmosphere will tend to push in and squash the gas. This is what give rise to what we commonly think of as "suction": really, it is the atmosphere "pushing" rather than anything "pulling".

    In early steam engines, the power stroke exploited this. The cylinder was filled with steam at only a little above atmospheric pressure (early boilers were cast iron and blew up if you pressurised them much). Then, a spray of cold water was injected into the cylinder, causing the steam to condense rapidly. As the steam had displaced most of the air from the cylinder, when the steam condensed it left a partial vacuum (=pressure well below atmospheric). The resulting "suction" (=really the atmosphere pushing, from the outside, with little to oppose it) caused the piston to move powerfully into the cylinder. As a matter of fact, even in later steam engines, and in steam turbines, there is always a condenser in the exhaust circuit, which removes all the pressure of the steam and thus creates a partial vacuum on the exhaust side of the engine. This adds to the total pressure difference in the engine and hence to its power output.

    So in a way you are also right that the "closing in" of the molecules provides a source of extractable energy.
    Wow thanks for this detailed explanation. It is amazing how we can manipulate our surroundings to benefit us. I had never known the science behind a heat engine but I have a really good understanding of it now. I will look into the 2nd Law of Thermodynamics. Thanks for taking the time to reply to this thread and helping me understand the world around me a little better.
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    Forum Sophomore confusedasyou's Avatar
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    Quote Originally Posted by KJW View Post
    The question you ask is the essence of the second law of thermodynamics as it was originally formulated. The answer is no, you cannot extract work energy from a single temperature source. You must have a temperature difference in order to extract work from thermal energy.
    Thank you for your time and your responce to this thread. Will I find the answer, as to why we cannot gather work energy from a single temperature, by reading about the 2nd Law of Thermodynamics? Is there a certain subject that you can point me to that will help me understand why this is not possible? Thank you again for your reply. I really do appreciate it.
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    Quote Originally Posted by Harold14370 View Post
    Quote Originally Posted by confusedasyou View Post
    So is there a way to collect the energy created from the movement of these particles?
    Any thermodynamic engine does just that. Steam turbines, automobile engines, etc. As mentioned, you do need a temperature difference.
    Thank you very much for taking the time to respond to this thread. I really do appreciate every bit of communication I receive. I never knew the science of how gasoline works in cars but can see now how it does.
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