Now I get to do something with that force scale I built. I had a request some time ago to talk about friction. Friction is surprisingly complicated. When two surfaces rub against each other, why is ...

This article has been updated to include comments from Raymond Goldstein and Patrick Warren. It is a mathematical puzzle that stumped Galileo, but researchers in France think they have discovered how ...

Here’s the rub with friction — scientists don’t really know how it works. Although humans have been harnessing its power since rubbing two sticks together to build the first fire, the physics of ...