What Causes Static Cling in Clothes?

[wmrunner24]

Homework Statement

Static cling causes your clothes to stick together.
What causes this to happen?

1. the nature of the material
2. external forces to the clothes
3. forces of nature
4. friction created by tumbling clothes

Homework Equations

None

The Attempt at a Solution

My original hunch was the nature of the material, but now, I'm not so sure. I poked around online and discovered that there were three conditions.

"From the above, it can be summarized that static cling occurs if the following conditions are fulfilled:

* When there is friction between two materials
* The two materials are not the same but are electrically insulating
* Dry conditions exist with humidity at very low levels (this is conducive to the transferring of electrons)"

-taken from http://www.whatisstaticcling.com/why_static_cling_occurs.html

So I'm now inclined to believe its either the nature of the material or the friction between them. I'm kinda leaning toward friction, but I'm not sure. Any ideas?

 

[RoyalCat]

What -force- acts between the two pieces of cloth to pull them together? What is its nature, and what is necessary for it to exist?

Once you answer those two questions, you'll know why friction results in this force appearing.