Isaac Newton
Isaac Newton was a student at Cambridge University when the black death, also called the Great Plague, struck nearby London again. It was a horrible disease that the people did not know how to cure. Thousands died. Misery, despair, and fear were everywhere. Soon fear turned to panic. Riots broke out in the streets. London was locked down, and Cambridge was closed. Isaac retreated to his mother’s home in the countryside. Isaac Newton had many questions about the universe. He did not let the closing of the school close his mind. He used the time to experiment and think. One day he went into his mother’s garden. It was a beautiful sunny day, but he hardly noticed. He was sitting in the shade of an apple tree, deep in thought. As he sat there, an apple fell from the tree. It plummeted straight down.
That caused him to ask questions. Why did the apple fall straight down? Why did it fall at all? Why did it not float in the air or fall up? And why do all things fall to the ground when not supported? Why does everything seem stuck to the earth? To answer his questions, Newton developed a new kind of math. He labored over many equations. He eventually figured out that all objects attract other objects. He reasoned that since the earth is so large, its force must be very strong. So, when the apple broke from the branch, it was pulled toward the center of the earth by this force. He believed that this was the same force that kept the moon from flying away from the earth. He wrote about it in a book called Principia. He called his idea the Law of Universal Gravitation. Isaac Newton discovered much about gravity!
Epilogue
The story of the falling apple is likely true, though the apple probably did not fall on his head as some stories say. The incident is included in Stukeley’s biography of Isaac Newton, Memories of Sir Isaac Newton’s Life
