Gravity is, at heart, a mystery. Yes, we can talk about curvature of space-time and perhaps make analogies with stretched rubber sheets. But we don’t know why mass causes space-time to curve. To put ...

Introduction Did you know that playground swings can provide a good lesson in physics—as well as lots of fun? The back-and-forth motion of a swing is an example of a pendulum. We see pendulums in ...

While most of us take gravity for granted, physicists have a big problem with it. Their beef: As forces go, gravity is implausibly feeble. (Try asking a physicist why a kitchen magnet can pick up a ...

Scientific American is the authority on science and technology for a general audience, with coverage that explains how research changes our understanding of the world and shapes our lives. First ...