What causes texture on surfaces?

[OrigamiCaptain]

I know that we aren't touching anything because atoms are repelling because electron can't touch each other.

What I'm trying to figure out is texture.

I think the reason we feel texture is because of the variance in atoms in a particular spot. For example a table is smooth because the atoms are about the same distance from the same distance from your hand or finger. If there is a scuff on a table then the number of atoms in that location is scraped off leading you to feel the difference in repulsion.

Am I thinking about this right?

If you need to use math just be aware that I haven't had calculus, but have had precalc/trig.

Thank you for your help.

 

[Drakkith]

That's pretty much correct as far as I know. A very smooth surface, such as a polished mirror used in a high quality telescope, will have a surface that is very even, with surface irregularities perhaps tens of nanometers in height. A rough surface will have surface irregularities that are much larger, perhaps hundreds of micrometers if not larger. For example, 100 grit sandpaper (a medium grit that is between coarse and fine) has particles roughly 140-160 micrometers in size, while 20 grit (very, very coarse) has particles about 1000 micrometers (1 mm) in size.

Nickes, gouges, pits, bumps, and other types of damage to a surface will affect the texture based on how large they are and how many are in any given area.