bbc

A BBC Earth clip from Super Powered Owls in which the team uses sensitive sound equipment to compare owl flight with other birds. It shows why owls fly almost silently.

Hans Rosling uses augmented-reality animation to show 200 countries over 200 years in four minutes, built from 120,000 data points. It tracks life expectancy and income to show the world's development.

Marcus du Sautoy of the BBC demonstrates the wisdom of the crowd, showing that averaging many guesses of jelly beans in a jar lands near the true count.

A clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains heat as the jiggling of atoms and how we perceive it as hot and cold.

A short clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains how a train stays on the track. He covers the geometry of tapered wheels that steer the train back toward the center of the rails.

Richard Feynman, in a clip from the BBC series Fun to Imagine, takes on the puzzle of why mirrors seem to swap left and right but not top and bottom.