Internal motion of atoms and collisions

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Discussion Overview

The discussion revolves around the nature of atomic collisions, particularly focusing on whether considering only the internal motion of atoms leads to all collisions being elastic. Participants explore the implications of this perspective at both macro and micro levels, touching on concepts from quantum mechanics and thermodynamics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that if only the internal motion of atoms is considered, all collisions would be elastic.
  • Another participant counters by introducing quantum mechanics, noting that inelastic scattering, such as the Raman process and deep inelastic scattering, occurs at the quantum level.
  • A different viewpoint emphasizes that at a macro level, collisions may appear inelastic due to the merging of masses, but at a micro level, the internal motion of particles could imply elastic behavior.
  • One participant raises the question of how reversible mechanical laws can lead to irreversible thermodynamic processes.
  • Another participant acknowledges that while collisions can be elastic, they may lead to effectively irreversible changes, such as splitting an atom, which complicates the notion of reversibility.

Areas of Agreement / Disagreement

Participants express differing views on the nature of collisions, with some supporting the idea that all collisions could be elastic under certain conditions, while others highlight the occurrence of inelastic processes, particularly at the quantum level. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations regarding the assumptions made about the definitions of elastic and inelastic collisions, as well as the scope of the discussion between macro and micro levels. The implications of energy levels in collisions and their effects on reversibility are also not fully resolved.

Dr.Brain
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I was thinking , if we take into account oly the internal motion of atoms , all collisions will turn out to be elastic. Wont they be?
 
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In quantum mechanics, photons can scatter off atoms inelastically in what is called a Raman process. Also, the technique known as deep inelastic scattering is a powerful tool for studying the structure of nuclei. So inelastic scattering can happen even at the quantum level.
 
Last edited:
I am talking at macro-level . The collisions which look to be inelastic viewed form outside due to merging of masses ( in the case of inelastic collisions in which the the two rigid bodies don't mix up after collision but retain their boundary even though they may change their shapes ), but their particles were not allowed to enter each other's boundaries , which would imply they retorted back after collision . At micro-level thsi would mean everything happened elastically even though from outside it appears to be inelastic.

(This thread I posted because I looked at collision from a different point of view..I am in no mood to change any laws...)

BJ
 
It looks like you are trying to address the question how reversible mechanical laws produce irreversible thermodynamics...
 
Dr.Brain said:
I was thinking , if we take into account oly the internal motion of atoms , all collisions will turn out to be elastic. Wont they be?

Yes, but some of the collisions may make essentially irreverible changes
even though they are elastic. For example, if a collision is energetic enough
you could split an atom. While this is reversible in principle, it would be very
unlikely that you could put the atoms back the way they were. So in
practice there is effective irreverability even though each individual
transformation is reversible.
 

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