What is Touching: Examining the Microscopic Level

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Discussion Overview

The discussion explores the concept of "touching" at the microscopic level, questioning what occurs when two objects come into contact, particularly focusing on atomic and molecular interactions. The scope includes theoretical considerations and conceptual clarifications regarding the nature of contact between matter.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that on a microscopic level, nothing is truly "touching" due to the wave-like nature of elementary particles, which are spread out over space.
  • It is suggested that what is felt during touching is the electric repulsion between the outer electrons of atoms in the fingers, rather than direct contact.
  • One participant notes that the concept of "touching" becomes less meaningful at the molecular scale, indicating a shift in understanding as one examines smaller scales.
  • Another viewpoint suggests that touching involves both electric repulsion and the Pauli exclusion principle, although this claim lacks supporting references.
  • There is uncertainty regarding how close atoms are to each other during contact, with some suggesting they may be a significant distance apart at the microscopic level.

Areas of Agreement / Disagreement

Participants generally agree that defining "touching" at the microscopic level is complex and that electric forces play a crucial role. However, there are competing views on the implications of this complexity, particularly regarding the nature of particles and their interactions.

Contextual Notes

Limitations include the lack of consensus on the definitions of "touching" and the specific distances involved at the atomic level. The discussion also reflects varying interpretations of quantum mechanics and its implications for physical contact.

leroyjenkens
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If you touch your fingers together, what exactly is touching? When you touch your thumb and your index finger together, you feel them touching, but on a microscopic level, is anything really touching? If you somehow looked at all the atoms that are closest to each other from each finger, how close would they be?
 
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No, probably nothing is 'touching'. In fact, it's very hard to even define 'touching' on the microscopic level, since every elementary particle is in fact a wave or wave packet, and is in general smeared out over all space. So, in a sense, all particles are touching each other. Of course, the wavefunctions of two particles only 'feel' each other if they are very very close.

What you feel when you touch your fingers together is the electric repulsion between the outer electrons of the atoms in one finger and those in the other finger.

I'm not sure how close they would be, but in microscopic terms, probably a large distance apart!
 
On a microscopic scale, still "touching". You have to go down to the molecular scale before the concept of "touching" starts to become a bit meaningless.
 
I believe on a molecular or atomic scale that touching is a combination of electric repulsion and the Pauli exclusion principle, but I don't have any references to back that up.
 
Nick89 said:
No, probably nothing is 'touching'. In fact, it's very hard to even define 'touching' on the microscopic level, since every elementary particle is in fact a wave or wave packet, and is in general smeared out over all space. So, in a sense, all particles are touching each other. Of course, the wavefunctions of two particles only 'feel' each other if they are very very close.

What you feel when you touch your fingers together is the electric repulsion between the outer electrons of the atoms in one finger and those in the other finger.

I'm not sure how close they would be, but in microscopic terms, probably a large distance apart!


I concur!
 

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