Sir Isaac Newton

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Sir Isaac Newton is one of the most important scientists in history. He studied how the universe works and formulated laws of physics to help people understand things like gravity, motion and light. Isaac Newton also invented the branch of mathematics known as calculus. It can be said that he used math to explain the world (or at least some things about it).

Isaac Newton was born in England in 1642. His interest in science developed early. As a boy, he made sundials, model windmills, a water clock and a mechanical carriage. In 1661, Isaac went to Cambridge College, where he earned a bachelors degree. Soon after he graduated in 1665, he had already begun to develop ideas in calculus, which he called his “method of fluxions.” He had also begun to think about the law of gravity, the concept for which he is probably most famous. According to legend, the inspiration for Newton’s study of gravity came one day when he saw an apple fall from a tree. He would later develop the law of gravity, which says that all objects in the universe have an attraction to each other. Larger objects have a stronger force of attraction (or gravitational pull) than smaller ones. The strength of the attraction gets smaller as the distance between the objects gets longer. Since the largest object on Earth is the earth itself (by far), objects are attracted to the earth when they fall. Newton also reasoned that gravity keeps the moon in orbit around the earth. Gravity does not pull the moon all the way to the earth’s surface because the distance between them is great enough to prevent that from happening.

Newton was also very interested in studying light. He performed experiments with a prism, which broke beams of light into bands of color. Until this time, the idea that white light consisted of bands of color had not been considered.

Sir Isaac Newton (cont’d)

Newton showed that colors were produced when bands of light are bent. The specific color depends on how much or how little the light bends.

In 1667, Newton returned to Cambridge to study for an advanced degree. He continued his work in the field of optics (light), and in 1668, he became the first scientist to build a reflecting telescope. Newton also refined his ideas about calculus during this time. In 1672, he published a paper that contained his ideas about light. His ideas were disputed and criticized for some time by other scientists, though none of the criticisms held up and his ideas finally became universally accepted. However, Newton was very sensitive to criticism, and for a while, he did not publish any of his ideas.

In 1679, Newton returned to his study of planetary orbits, which had started with his thoughts about the gravitational pull on the moon that kept in orbit around the earth. He developed the idea that planets orbit the sun based on the same principal. In other words, the force of gravity between the sun and the planets keeps the planets in orbit around the sun. Newton’s theories about planetary orbits were just part of his ideas about motion. In 1687, his first book, which contained all of his ideas about the laws of motion, was published. It was called Philosophiae Naturalis Principia Mathematica (Principia for short), and it was considered to be one of the most important books in the field of science.

In 1705, Queen Anne knighted Newton, and he became known as Sir Isaac Newton. Toward the end of his life, a controversy developed over who was the true inventor of calculus.

Sir Isaac Newton (cont’d)

Another mathematician had come up with the same ideas as Newton, though most historians believe that Newton invented calculus first.

Because of the way he applied mathematics to the study of the universe, Sir Isaac Newton’s has a permanent and important place in the history of science. Modern scientific theories like Einstein’s Theory of Relativity and the field of quantum physics are based on Isaac Newton’s ideas, which still hold up after more than 300 years.

Sir Isaac Newton Questions

1. Isaac Newton was a a. mathematician. b. astronomer. c. physicist. d. All of these

2. Which of the following was not among the things that Newton studied? a. light b. weather c. planetary orbits d. calculus

3. Legend has it that when Newton saw an apple fall from a tree, he began to thing about a. the planets. b. the force that would later be called gravity. c. the best way to make apple pie. d. why apples are red.

4. Why doesn’t gravity cause the moon to fall to the earth? a. The moon is too small. b. The moon is too far away. c. The sun has a stronger pull on the moon than the earth does. d. Both a and b

5. Why did Newton stop publishing his ideas for a while? a. He hated to write. b. He didn’t have time to write. c. He was afraid he would be criticized. d. He was not allowed to publish his ideas.

Sir Isaac Newton Questions (cont’d)

6. Isaac Newton was the first scientist to build a a. telescope. b. telephone. c. microscope. d. microphone.

7. A prism a. bends light. b. separates light into bands of color. c. Both of these d. Neither of these

8. Isaac Newton is called Sir because a. people have great respect for him. b. all English scientists are called Sir. c. he was knighted by the Queen of England. d. he was a professor at Cambridge.

9. Isaac Newton was able to explain how the universe works by using a. light. b. mathematics. c. gravity. d. his religious beliefs.

10.Explain the Law of Gravity in your own words.

Sir Isaac Newton Answers

1. d 2. b 3. b 4. d 5. c 6. a 7. c 8. c 9. b 10. Answers will vary but should contain the following ideas: All objects in the universe have an attraction to each other. Larger objects have a stronger force of attraction (or gravitational pull) than smaller ones. The strength of the attraction gets smaller as the distance between the objects gets farther apart.