What electromagnetic forces cause push and pull at contact surfaces?

[debayan]

how can wec trace the origin of push and pull to electromagnetic forces? I mean when we push a thing what actually are we doing? What are the atoms at the contact surface actually doing?

 

[Mentz114]

The electrons in the outer shells of the atoms making up the materials coming into contact will repel each other with the (very strong) force between like charges. That's why you can't walk through walls, even though you and the walls are mainly empty space.

 

[HallsofIvy]

Note that when you "pull" an object, whether with you hand, a rope, chain, etc., you are wrapping your hand, rope, etc. around some part of the object so it really is a "push". Oh- and electrons don't actually "come into contact". Mentz114 meant that their electric fields repel one another.