Isaac Newton: 5 Things You Should Know

Question: In 1665, a plague shut Cambridge University and sent Isaac Newton home. Why did those months off become so famous?

Answer: Newton’s biggest ideas took shape in his early 20s, while he worked alone at his family’s farm in Woolsthorpe. A crisis gave him time to think, and he used it to reshape science.

Question: Newton said watching an apple fall made him wonder about the Moon. What connection did he see between the apple and the Moon?

Answer: Newton realized gravity isn’t limited to Earth: the same pull works across space. This idea, called universal gravitation, explained the motion of moons and planets.

Question: For centuries, people thought moving things naturally slow down and stop. Why does a hockey puck glide so far on smooth ice?

Answer: This is Newton’s First Law of Motion, also called inertia: objects keep doing what they’re doing until a force changes their motion. Friction is why things on Earth seem to stop on their own.

Question: People once believed a glass prism added color to white sunlight. What did Newton prove when he passed light through prisms?

Answer: Newton showed that white light is actually a blend of every color in the rainbow. His work on light also led him to build a new kind of telescope that used mirrors instead of lenses.

Question: In 1687, Newton published the Principia, a book many call the most important in science. What did the book finally explain?

Answer: The Principia laid out Newton’s three laws of motion and universal gravitation as one system. For the first time, the same rules explained both a falling rock and an orbiting planet.