The Foucault pendulum (English pronunciation: /fuːˈkoʊ/ foo-koh; French pronunciation: [fuˈko]), or Foucault's pendulum, named after the French physicist Léon Foucault, is a simple device conceived as an experiment to demonstrate the rotation of the Earth. While it had long been known that the Earth rotates, the introduction of the Foucault pendulum in 1851 was the first simple proof of the rotation in an easy-to-see experiment.
The beautiful astronaut book Umberto Eco wrote to teach children about semiotics and tolerance
Umberto Eco is best known for his novels, like Foucault's Pendulum and The Name of the Rose, but he also wrote a handful of children's books. In his marvelous book The Three Astronauts, Eco offered children a lesson on tolerance, while also training their brains in basic semiotics.