Isaac Newton was a famous scientist and mathematician from England. He lived long ago. He was born in the manor house at Woolsthorpe, in England. His family were farmers. Newton went to Trinity College. It is part of Cambridge University. Then a sickness called the plague closed Cambridge University. So Newton went home to Woolsthorpe. Newton did important work in mathematics, in the study of light, and in the study of how things move.
While away from Cambridge because of the plague, Newton began important work in mathematics, light, physics and astronomy. He did this in less than two years. He shone sunlight through a glass prism. He saw a band of colors. He split white light into colors with one prism. Then he used a second prism to join the colors back into white light. White light is made of all the colors of the rainbow. Newton showed this.
Telescopes with glass lenses showed blurry colors. A mirror reflects all colors of light by the same amount. So a mirror telescope fixes this. Newton made a telescope that uses a mirror. In 1669 he became the Lucasian Professor at Cambridge. It is a professor's chair that Isaac Barrow had held.
Newton's first law says a still object stays still. A moving object keeps moving the same way, unless a force acts on it. His third law says that when one object pushes on another, the second pushes back just as hard in the opposite direction. Newton wrote that if you press a stone with your finger, the stone also presses on your finger. His second law says a bigger force changes an object's motion more. People write it as F=ma. That means force equals mass times acceleration.
Newton told a story about watching an apple fall from a tree. No one knows for sure if an apple really fell the way the story says. The part where it hits him on the head is called a myth. Newton said that everything pulls on everything else. He called this pull gravity. The farther apart two things are, the weaker the pull of gravity between them. The Earth pulls on the Moon with gravity. That pull keeps the Moon going around the Earth.
Newton wrote a famous book about how things move. It is called the Principia. His friend Edmond Halley paid to have the Principia printed. Newton's laws of motion and gravity became the base of classical mechanics. That is the study of how large things move. Newton's laws helped scientists understand how the planets move around the Sun and how the Moon moves around the Earth.
Newton was elected President of the Royal Society in 1703. That is a group of scientists. At the Royal Mint, Newton helped take old coins out of use. The Mint replaced them with more reliable ones. Newton lived to be 84 years old. He is buried in Westminster Abbey in London. Newton's laws are still used to reach the Moon, Mars and other places beyond Earth.
Words to know
- plague: a bad sickness
- prism: light-splitting glass
- gravity: pull between things
- myth: story, not fact
- mechanics: study of motion
