# Particle attraction

If you have two particles of opposite electrical charge in proximity, what actually sets them in motion? As a an analogy, if you have two balls in either end of a tube and remove the air between them, outside pressure will push them together. What is the equivalent process at the particle level?

Drakkith
Staff Emeritus
The particles exert an attractive electrical force on each other, resulting in an acceleration of each particle towards the other. In your example, the air molecules exerts a repulsive force on the balls when they collide with them, which pushes them together.

See here: http://en.wikipedia.org/wiki/Coulomb's_law

A.T.
If you have two particles of opposite electrical charge in proximity, what actually sets them in motion? As a an analogy, if you have two balls in either end of a tube and remove the air between them, outside pressure will push them together.
That is not an analogy, but an example of the very same force. The electrons in the air atoms and the ball atoms are repelling each other.

The particles exert an attractive electrical force on each other, resulting in an acceleration of each particle towards the other. In your example, the air molecules exerts a repulsive force on the balls when they collide with them, which pushes them together.

See here: http://en.wikipedia.org/wiki/Coulomb's_law

The question is why do they accelerate. The provided some information on virtual particle exchange, that's what I'm trying to get my head around.

Drakkith
Staff Emeritus