history
For 2000 years, the Aristotelian doctrine that nature abhors a vacuum blocked the conceptual leap that the atmosphere has weight. Torricelli's 1643 mercury tube was a thought experiment as much as a device: a column 76 cm tall that balanced against an invisible ocean of air.
biology
An archerfish hovers below the water and knocks an insect off an overhanging leaf with a precisely aimed water jet. The trick requires correcting for refraction at the water-air boundary, computing for ballistic trajectory through air, and learning the target's location through other fish's ...
biology
The Saharan silver ant forages on sand at 70 degrees Celsius, hotter than the lethal limit for almost any animal. It survives via a combination of triangular hair geometry that reflects near-infrared light and radiates heat in the mid-infrared, the longest legs of any ant species, heat-shock...
science
Scincus scincus is a 20-centimeter lizard that lives in the dunes of the Sahara and the Arabian Peninsula. When threatened, it dives into loose sand and disappears, then propagates through the sand at remarkable speeds with no limbs visible. The biomechanics of how the lizard moves through a subs...
science
A 50-gram lizard hangs from polished glass by a single toe. The mechanism is not suction or stickiness or claws but a brute multiplication of contact area down to molecular scales, and the engineering implications are still being worked out 25 years after the discovery.
biology
Most transparent animals are aquatic, where the refractive index of the medium matches their tissue. Air is a much harder problem. The glasswing butterfly solved it 30 million years ago with nanostructured wings that engineers spent the 2010s trying to imitate for solar panels and screens.
science
The European robin's magnetic compass works only with light, only in the right-eye, and only when oriented within a narrow band of intensities. The reason for these constraints points at a chemical mechanism that uses quantum-mechanical superposition to read the Earth's magnetic field.
biology
A gecko can hang from a polished glass ceiling by a single toe. The mechanism is not suction, glue, friction, or static electricity. It is van der Waals forces multiplied across a hierarchy of structures so fine that one toe pad has more contact points than there are people on Earth.
mathematics
Roger Penrose discovered in 1974 that two simple shapes can tile the plane forever without ever repeating. The discovery solved an open mathematical problem and, a decade later, accidentally revealed a class of crystals that Linus Pauling spent the rest of his career denying existed.
history
The compass arrived in Europe sometime in the 12th century from sources that may or may not have been Chinese. Within 200 years it had restructured Mediterranean trade, cracked open the Atlantic, and made global navigation possible
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 ...
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.