Lightning defied explanation for a century. Colliding ice... | funfact.wiki | funfact.wiki
Lightning defied explanation for a century. Colliding ice grains separate charge, but symmetric ice makes no electricity when pressed — piezoelectricity fails. In 2025, bending ice was shown to break symmetry and generate it: flexoelectricity.
Hot water can freeze faster than cold — a phenomenon called the Mpemba effect. Known since Aristotle but still unexplained, it was named after Tanzanian student Erasto Mpemba, whose question physicist Denis Osborne took seriously enough to research together.
In 1818, Siméon Denis Poisson argued that if light were a wave, a bright spot should appear at the center of a circular object's shadow — which he thought was absurd. But when Arago actually ran the experiment, the bright spot appeared, proving light's wave nature.
A train's left and right wheels share one axle, always spinning together. Yet turns are possible because the wheels are conical. On a curve, centrifugal force shifts the train, changing each wheel's contact diameter and allowing a smooth turn.
An airplane doesn't turn by steering left or right like a car. With no friction in the air, that would cause it to drift sideways. Instead, it banks its body to redirect lift, and the horizontal component acts as centripetal force to make the turn.