The Maestro explains how the revolutionary ideas of the early discoverers, which we now take for granted, were not always well received. Before Galileo, for example, everyone believed that the sun and all the other planets revolved around the earth!

In this video, a young Galileo gets one of his first revolutionary ideas on how to measure time. Pretty impressive for a fourteen-year-old, huh?

Episode nine of this series focuses on Galileo, a prolific inventor and scientist. He discovered the principle of the simple pendulum motion, very useful in the measure of time and later in the making of clocks.

In part four of this episode on "The Discoverers," Galileo, now a reputable scholar at the University of Padua, proceeds to make a telescope out of lenses with the help of his instrument maker, Marc'Antonio. In this cartoon, an attempt is made to explain Galileo's discoveries.

In part five of this episode on "The Discoverers," Galileo is warned. His belief that the Earth revolves around the sun is sacrilegious. Giordano Bruno, who claimed this fact, was burned as a heretic by the Inquisition Tribunal.

Galileo is about to throw caution to the wind and reveal his startling discoveries about planet Earth.

Galileo is under close scrutiny because of his Copernican views. Unfazed, he carries on his research and his teachings. Will the Inquisition bring his demise or will his powerful friends, Pope Urban VIII among them, protect him?

Galileo faces an uncertain future. Behind the scenes are political and religious intrigues and enemies plotting his downfall. The Pope, until now sympathetic to Galileo, has a change of heart. Under pressure from all sides and insulted by his latest works, The Dialogue Concerning the Two Chief World Systems, portraying the Church's view through the character Simplicio (Simpleton), the pope finally sends Galileo to the Inquisition Tribunal.

Galileo is in prison. He tries one more time to prove his theories to his inquisitor. But he finally recants during the trial saying the famous sentence: "and yet... it turns"

Have you ever wondered what a blood platelet actually does? Find out as the Once Upon a Time... series tackles biology.

Although antibodies mainly protect against bacteria, viruses, and other foreign substances, sometimes they can also attack your own blood cells! But this cartoon explains why you don't have to worry too much about that happening.

When the young platelets in this cartoon decide to have some fun and create a sort of "platelet pyramid" out of themselves, their older friend warns them that they could be causing a blood clot!

Watch the blood platelets in action in this fun cartoon. Moral of the story? Always listen to your mother.

The platelets vanquish the bacteria in the final installment of this animated series on blood. Who knew that a simple cut could be so epic?

Find out what happens in the body when we eat: the roles that teeth, the tongue, and nerve impulses play. But let's not forget about umami!