This persnickety number determines the strength of magnetic fields. It figures in everything from motors and generators to audio speakers. Oh, and without it we’d live in eternal darkness.

Your everyday notion of forces probably includes pushing and pulling and similar actions. Technically, when something is pushed or pulled we say that "a force is applied to the object". What happens ...

The little spheres represent water molecules. Molecules are in constant motion. The attractions water molecules have for each other keep them close together. They can move past each other, but their ...

People usually think of a time constant as the time it takes a first order system to change 63% of the way to the steady state value in response to a step change in the input -- it's basically a ...