Generating Energy from Molecular Motion

In summary, "Generating Energy from Molecular Motion" discusses the innovative methods of harnessing energy from the kinetic activity of molecules. It explores techniques such as converting thermal energy into usable power through nanotechnology and advanced materials that exploit molecular vibrations. The article highlights the potential applications in sustainable energy solutions and the efficiency gains from utilizing molecular motion, promising a new frontier in energy generation that could address global energy challenges.
  • #1
painter
4
4
This question really troubles me.
Since we all know that the molecules are in perpetual random motion, why can't we make a perpetual motion machine by using molecular's always-moving energy??

I‘m a Grade 9 student and I'm unsure about this.

:doh::doh::doh:
 
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  • #3
Hi @painter and welcome to PF!

You seem to be aware that perpetual motion machines are impossible, which is good. You just need to recognize that the word "perpetual" is the key. In the case of random motion of molecules, any such collection of molecules only has a finite amount of energy in it due to random motion. You could conceivably convert that finite amount of energy into some other form to do useful work (though even then there are other limitations involved), but that wouldn't be "perpetual" motion because once that finite amount of energy was used up, you would be done: there would be no more energy left and whatever you were doing with the energy would stop. The reason the random motion of molecules is "perpetual" is that the energy in that random motion isn't being converted into anything else; it's not doing any useful work at all.
 
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  • #4
painter said:
it MUST have lost some of its energy when being converted into something else (is that?)
That's right: by conservation of energy, if you use some of the energy contained in the random motion of molecules for something else, that energy is no longer there in the random motion of molecules.
 
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  • #5
PeterDonis said:
Moderator's note: Thread moved to Classical Physics forum.
And thank you for moving the thread to a right place-----I'm new here and I really have no idea where to put it.
 
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  • #6
PeterDonis said:
That's right: by conservation of energy, if you use some of the energy contained in the random motion of molecules for something else, that energy is no longer there in the random motion of molecules.
I got it !! Thank you veeeeery much😃😃😃🤩
 
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  • #7
painter said:
I got it !! Thank you veeeeery much😃😃😃🤩
You're welcome!
 
  • #9
painter said:
Since we all know that the molecules are in perpetual random motion, why can't we make a perpetual motion machine by using molecular's always-moving energy??
We can already make machines that take advantage of a "molecule's always-moving energy". That's thermal energy, and machines that convert heat into other forms of work already exist. A stirling cycle engine does converts heat into mechanical motion, and thermionic generators can convert heat into electricity (at its most basic level, so does a thermocouple).

None of this is perpetual motion, however. When you extract heat energy from a material, the motion of its molecules decreases.
 
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  • #10
While I like Feynman's treatment, I would not suggest it to a 9th grader.
 

FAQ: Generating Energy from Molecular Motion

What is molecular motion and how does it relate to energy generation?

Molecular motion refers to the movement of molecules, which can be influenced by temperature, pressure, and other environmental factors. In the context of energy generation, harnessing this motion can convert kinetic energy into usable electrical energy, often through mechanisms such as piezoelectric materials or thermoelectric generators that exploit temperature differences.

What technologies are currently used to generate energy from molecular motion?

Several technologies are employed to generate energy from molecular motion, including piezoelectric devices, which convert mechanical stress into electrical energy, and thermoelectric generators, which convert temperature gradients into electrical voltage. Additionally, nanogenerators that use nanostructured materials are being developed to capture energy from small-scale molecular movements.

What are the advantages of generating energy from molecular motion?

Generating energy from molecular motion has several advantages, including the potential for renewable energy sources, the ability to harness energy from ambient sources (like vibrations and heat), and the opportunity for energy harvesting in small-scale applications. This approach can lead to sustainable energy solutions that reduce reliance on fossil fuels and diminish environmental impact.

What are the challenges associated with harnessing energy from molecular motion?

Challenges in harnessing energy from molecular motion include the efficiency of energy conversion, the scalability of technologies, and the need for materials that can withstand repeated stress without degrading. Additionally, optimizing these systems for practical applications while minimizing costs and maximizing output remains a significant hurdle in the field.

What future developments can we expect in this area of energy generation?

Future developments in generating energy from molecular motion may include advancements in nanotechnology to improve the efficiency and effectiveness of energy harvesting devices, the integration of smart materials that respond dynamically to environmental changes, and the development of hybrid systems that combine multiple energy generation methods for enhanced performance. Research is also focusing on improving the sustainability and affordability of these technologies to make them more accessible for widespread use.

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