Monday, 20 May 2013

Short stories from Sir Isaac Newton's life

Isaac Newton set down the laws of motion and gravity. He didn't really "discover" them, but quantified them and showed how they were related and how they worked. He also (with Liebnitz, who worked independently) brought us the calculus, an extraordinary tool of mathematics.

Isaac Newton is arguably one of the most influential scientists in history. Though he lived in the late 1600s, many of his discoveries still affect us in the present. His various theories still hold true even centuries after his death and countless experiments. The scientists able to improve upon his work became famous themselves. Some would say that he was the greatest product of the Enlightenment, the explosion of intellectual knowledge that occurred in his century. Here is a collection of short stories from his life depicting how he discovered various laws of physics and mathematics.

Isaac and the Bully

Isaac Newton was a shy, quiet boy growing up on a farm in England 300 years ago. He was not a very good student and nobody paid much attention to him. Nobody that is, except the school bully. One day the bully punched Isaac in the stomach. That hurt, and that got Isaac very mad! He pulled himself up straight and fought back. Isaac pushed the bully onto the ground and rubbed his face in the mud. All the other kids hated the bully and came and cheered for Isaac.
So Isaac taught the bully a lesson, but he wasn't satisfied with that. Now that he knew he could fight better than the bully, he wanted to prove that he could do anything better than the bully. So he started paying attention to school and studying hard. He was soon the top of his class, proving he was smarter than the bully too.
Isaac Newton kept on studying and when he grew up he became a math professor at Cambridge University. He discovered lots of important things and is one of the most famous scientists who ever lived. 

Isaac and the Wind

If Isaac was so smart, then why didn't he always do well at school? Well, how well somebody does at school isn't the whole story about them. Its good to remember that just because somebody has trouble with something at school, it doesn't mean they are stupid. Isaac Newton proved that!
I expect that one reason he didn't do well for a long time was that he was always thinking about things. Its just that usually the things he was thinking about weren't the things other people wanted him to think about.
For example, one time there was a terrible wind storm on the farm. His mother was worried that the wind might break gates, doors and shutters. She sent Isaac out to check all over the farm buildings and fences to make sure there wasn't anything flapping in the wind.
Isaac went out, but he didn't come back. He looked at the strong wind blowing things all around and thought "I wonder ..."
His mother waited and waited, then went out looking for him. When she found him, he was jumping up off a fence over and over to see how far the wind would carry him. He had gotten thinking about how strong the wind was, and forgot completely about everything else.
Isaac loved the wind, so of course he loved kites. He even used to fly kites in the dark. He would tie a small lamp to the tail of the kite so he could see it up in the night sky. However, people were very superstitious when he lived. When the neighbors saw a light floating in the sky at night they were worried about ghosts, or witches, or other things. When Isaac heard about this he laughed, but he decided he better stop flying the kite at night.

Comets and Apple Trees

One day Isaac was reading a book under an apple tree on the farm. An apple fell out of the tree - bonk! Ow!
Now, for most people that would be the end of the story, but not for Isaac. Not for somebody who just couldn't stop asking why all the time.
Why did the apple fall out of the tree? Does everything fall? What makes things fall? Can anything stop things from falling? Are the sun, moon, and stars falling? Why don't they ever hit the ground?
So many questions. Newton spent many years answering these questions by thinking and doing experiments. He made up the law of gravity. According to this law everything pulled everything else to itself by a force called gravity. How strong that force is depends on how heavy the things are and how close together.
So even two apples pull toward each other. But, the force is so small that you need a very careful experiment to measure it. The reason that things fall toward the ground is that the earth we live on is so very heavy, and we are so close to it.
Newton's law of gravity not only explained how things fall on earth, but how planets move around the sun and how moons move around planets. A friend of his, Edmund Halley, decided to try Newton's theory on comets. People had been studying comets for hundreds of years without figuring them out, so he decided to study their reports and compare them to Newton's theories.
Up til then people had thought that comets just came and went, and that nobody could know when or why. But Newton's law of gravity gave rules that Halley could use to study the records of comets. He found some reports of a big bright comet that he was sure was the same one, coming back every 75 years. He predicted when it would come back next.
If anybody still didn't believe Newton, then the appearance of Halley's Comet just when Halley had predicted it using Newtons ideas was enough to convince them. Halley's comet has come a few times since then, always right on schedule. You'll be able to see it on its next trip near the sun and earth when you're old enough to be a grandparent.

Newton and Hooke

Do you know anybody who always has to be first? Maybe its your brother or sister, or a friend. When you say you learned something, they say "I already knew that". When you're going to do something, they say "I already did that".
There was another famous scientist named Robert Hooke who was very jealous of Netwon. Whenever Newton announced he had discovered something, Hooke would say "I already discovered that first, I just didn't tell anybody yet." This made Newton very mad.
Everybody makes mistakes sometimes, even very smart people like Newton. One time when Newton made a mistake, Hooke was the first to discover the mistake and tell everybody about it. Newton was mad and embarrassed. He didn't like to make mistakes, but he really hated that it was Hooke who figured out the mistake. Newton said that he would never tell anybody about his discoveries again. He didn't want to ever have Hooke catch him making a mistake again. In a while though, Newton realized how silly this was and started telling about his discoveries again.
Newton wrote a big book called Principia. This book told all about how things push and pull, and gave lots of examples of how machines work and how things like planets and comets move. It was a very important book, and scientists still like to read it, even though it is more than 300 years old. But guess what happened when he was writing it. Hooke found out about what he was writing and said "I already discovered that!" Newton was so angry that he decided not to write the book. It was a good thing that he again realized how silly it is to let somebody else bother you that much. He did finish writing it, and even mentioned some things that Hooke had done.

All the Colors of Light

Another important thing that Newton did was to figure out a lot about how light works. One day he bought a prism at the Stourbridge Fair. (This is a piece of glass shaped like a triangle.) He had it sitting on his desk, and noticed how when the sun shone on it, he got different colors out. This made him very curious. Does this change the light, or does the sunlight have lots of colors that the prism puts into different places? How does the prism do it?
To find the answers, Newton had to do some experiments. He first used his blinds to get a very thin sunbeam to hit the prism. This was important - to control the light that was coming in so that he knew exactly what he was starting with. He discovered that the separation of light was even clearer. There was red, then orange, then yellow, then green, and then blue.
Newton was pretty sure that what was happening was that the light from the sun had all these colors in it, and that what the prism was doing was bending them all to go into slightly different directions. To test this he got two prisms and a card with a hole in it. He used the first prism to get the sunlight to make different colors. Then he would choose a color and put the hole so than only that color went through into the next prism. He then had a very thin line of red, yellow or some other color of light going to the second prism.
He discovered that when the light came out of the other side of the next prism, it was still the same color as when it went in. So the prism doesn't change the light's color. What the prism did do was to bend the path the light went on, so that it hit a different place than when the prism wasn't there. When he tried different colors of light he found that the prism bent them all a little bit differently. That was why light that looked white, which had all the colors in it, made different colors when it went through the prism - the different colors all came out of it in slightly different directions.