What happens when two masses touch?

  • Context: Undergrad 
  • Thread starter Thread starter cowpuppy
  • Start date Start date
  • Tags Tags
    Two masses
Click For Summary

Discussion Overview

The discussion centers on the interaction between two masses when they come into contact, particularly focusing on the forces at play when charge-less masses collide. Participants explore the implications of classical and quantum physics in explaining this phenomenon.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the nature of the forces governing the interaction when two charge-less masses collide, noting that electromagnetic repulsion prevents direct contact.
  • Another participant references Van der Waals forces as a relevant concept for understanding interactions between neutral molecules.
  • A participant argues that classical physics cannot adequately explain the interaction, citing historical challenges and the role of quantum mechanics, specifically the exclusion principle and degeneracy pressure, in preventing particles from overlapping.
  • There is a clarification regarding the attribution of the exclusion principle to Pauli rather than Heisenberg, indicating some uncertainty about historical details.
  • One participant suggests that electromagnetic forces still influence adjacent neutral masses, as their electron clouds interact before any potential fusion or fission occurs.

Areas of Agreement / Disagreement

Participants express differing views on the adequacy of classical physics to explain the interaction of touching masses, with some emphasizing quantum mechanical principles while others reference classical forces. The discussion remains unresolved regarding the complete understanding of the forces involved.

Contextual Notes

Participants acknowledge limitations in historical understanding and the complexities of quantum mechanics versus classical explanations. There are unresolved aspects regarding the definitions and implications of forces at play when masses come into contact.

Who May Find This Useful

This discussion may be of interest to those exploring the intersections of classical and quantum physics, particularly in the context of particle interactions and the nature of forces at microscopic scales.

cowpuppy
Messages
8
Reaction score
0
What happens when two masses touch? I mean, really touch. When I touch something, I know that the atoms in my hand are separated by some distance from the object I am touching, due to mutual repulsion by the electromagnetic force.

So, if two charge-less masses were to collide with each other, what force governs that interaction?
 
Physics news on Phys.org
It's a question that simply cannot be answered by classical physics.

It was a big problem in the 19th Century that contemporary theory suggested that the most energetically favourable configuration of charged particle would be 'all on top of each other'.

It was only when Heisenberg came along that the 'exclusion principle' was formulated.

The idea is that these new laws predicted that two particles (like the neutral ones you mention) can never end up in the same place. As they get too close, the quantum mechanical 'degenerecy pressure' prevents them from ever 'overlapping'.

Not a great explanation, apologies.

Van der Waals forces are just one particular manifestation of classical electrostatics.

Incidentally, this degenerecy pressure is also the reason we never 'touch' anything ourselves. Classical electrostatics cannot account for that. Why would the atoms in our hand repel the atoms in the brick (or whatever)? Clasically, they would attract (due to polarisation within the atom), and then overlap, with the protons all hugging up to the electrons in a big particle soup.

Amazing to think that no-one before the beginning of the 20th century could even begin to explain why we don't fall through the floor.
 
opsb said:
It was only when Heisenberg came along that the 'exclusion principle' was formulated.

Do you mean pauli
 
Thanks, sorry. History a little shaky.
 
The electromagnetic force still plays it's part with adjacent neutral masses "touching"...like your hand and a baseball...because the neutral masses consist of electron clouds surrounding nuclei...and the electron clouds come into first "contact"...

If they REALLY "touch" they might fission or fuse as in bombs...or form a new compound like hydrogen and oxygen to form water...
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 35 ·
2
Replies
35
Views
5K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 55 ·
2
Replies
55
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 202 ·
7
Replies
202
Views
14K