© David Kaplan.
This figure represents how we believe friction works at the microscopic level. The picture to the left is a cartoon of the tire and road at their points of contact, where bits of each block each other from movement. The picture on the right is an even tighter close-up. Individual molecules interact with each other through the electromagnetic force. The molecules repel one another, preventing the tire from sliding freely across the surface of the road. (Unit: 2)