What Is Energy at a Microscopic Level?

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Discussion Overview

The discussion centers on the concept of energy at a microscopic level, exploring its definition, implications, and the nature of energy in physical phenomena. Participants examine theoretical aspects, conceptual clarifications, and the abstract nature of energy without reaching definitive conclusions.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant defines energy as the ability to perform work, specifically through the force-displacement relationship, and questions its nature at a microscopic level.
  • Another participant discusses the conservation of energy as a fundamental law, emphasizing its abstract nature and the lack of a concrete understanding of what energy is.
  • A third participant suggests that energy is a bookkeeping device, questioning the relevance of energy concepts at the molecular level, particularly in specific scenarios like potential energy.
  • There is a reference to Feynman's lectures to provide further context on the discussion of energy, indicating a desire to explore established ideas in physics.

Areas of Agreement / Disagreement

Participants express differing views on the nature of energy, with some emphasizing its abstract and mathematical properties while others challenge the applicability of energy concepts at the molecular level. No consensus is reached regarding the understanding of energy at a microscopic scale.

Contextual Notes

Participants highlight the abstractness of energy and its dependence on definitions, with unresolved questions about its mechanisms and implications at different scales.

nil1996
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Hello PF:smile:


Up till now i have learned that something that has the ability to do force*displacement is called energy.But what is energy at a microscopic level ?
 
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See last paragraph:

Richard Feynman said:
There is a fact, or if you wish, a law governing all natural phenomena that are known to date. There is no known exception to this law – it is exact so far as we know. The law is called the conservation of energy.

It states that there is a certain quantity, which we call “energy,” that does not change in the manifold changes that nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says there is a numerical quantity which does not change when something happens.

It is not a description of a mechanism, or anything concrete; it is a strange fact that when we calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same.

It is important to realize that in physics today, we have no knowledge of what energy “is.” We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. It is an abstract thing in that it does not tell us the mechanism or the reason for the various formulas.
 
To expand on this, it might be useful to read the entire chapter that the Feynman quote comes from:

http://www.feynmanlectures.info/docroot/I_04.html
 
I don't think it makes sense to talk about energy "at the molecular level". What in the world would the "potential energy of a rock sitting on a cliff" even mean "at the molecular level. Fundamentally, energy is a "bookkeeping" device. Every time we find a situation in which it appears that energy is NOT conserved, we define a new kind of energy to cover the difference!
 

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