physics
Sand is one of the most familiar materials on Earth and one of the most poorly understood by physics. It flows like a fluid, supports weight like a solid, exhibits force chains that physicists are still arguing about, and refuses to fit into the continuum equations that describe ...
mathematics
Cellular automata are the simplest possible computational systems and they exhibit some of the deepest behavior we know how to study. The schoolroom version is Conway's Game of Life. The mathematical reality is that the simplest known universal computer fits in three lines of pseudocode.
history
Before mechanical refrigeration, food had a small geography and a short timeline. The shift from local to global food systems happened in a generation, was driven by chemistry that almost killed the people who ran it, and changed the human diet more than any single agricultural innovation.
mathematics
When a dog runs at a duck swimming across a pond, the dog's path traces a pursuit curve. Pierre Bouguer worked out the mathematics in 1732. The same equations describe missile guidance, predator-prey dynamics, hot-pursuit problems in epidemiology, and the spiral arms of certain galaxies.
history
The well is the oldest piece of civic infrastructure that still works the way it did when it was invented. The Bronze Age innovations that solved problems we have largely forgotten existed, the strange persistence of medieval technology into the present, and the deep-aquifer engineering that qu
mathematics
Random numbers are simultaneously the most familiar and the most subtle objects in mathematics. The century of false starts, the philosophical puzzle of what randomness even means, the practical engineering of generators that fool sophisticated tests, and the cryptographic stakes when the engin
history
In 1942, the most beautiful woman in Hollywood patented a frequency-hopping spread spectrum system that the US Navy ignored, the FCC eventually ratified, and Bluetooth, GPS, and WiFi all use today. The story of Hedy Lamarr's other career — and what it reveals about who gets to be a scientist.
science
Glaciers are solid ice that flows downhill at speeds measured in meters per year, and the explanation involves crystal physics, pressure-melting, and the strange in-between behavior of materials near their melting point. A field guide to ice that creeps.
mathematics
Spirals appear at every scale in nature — galactic arms, hurricanes, ammonites, sunflowers, snail shells, the double helix. The reason is not coincidence; it is that a small number of mathematical processes generate spirals as their natural shape, and these processes recur at every scale where
science
A soap bubble is a small machine for solving a difficult mathematical problem: find the surface of minimum area enclosing a given volume. The fact that bubbles solve this problem instantly, by physics, has occupied mathematicians for two centuries — from Plateau's experiments with iron-wire frame...
history
Before 1883, every American city kept its own time, set by the local sun. Boston was 11 minutes ahead of New York, which was 5 minutes ahead of Philadelphia. Trains made this intolerable. The story of how four time zones replaced thousands of local solar times is a story about coordination proble...
math
In 1852 a London graduate student noticed he could color any map of England with four colors so that no adjacent counties shared a color. The conjecture took 124 years and the first major computer-assisted proof in mathematical history to settle. The story illuminates how a question that sounds