第11篇1-11

11.
When an Apple Falls
Imagine yourself under the cool shade of an apple tree. Your mind and body relax as you sit quietly, thinking. Suddenly, a ripe apple falls from the tree, narrowly missing your head.
Most of us would be thankful that the apple did not hit us. And that would be the end of it. But sometimes, an ordinary happening can lead to extraordinary results.
Such was the case in the 17th century.Isaac Newton spent his life working out many laws of physics. He wanted to figure out how things worked. For him, the world was his laboratory in those early days of science.
For a long time, he had been working on the “laws of motion" . One lucky day, as he was sitting in his study at his mother's country home, he looked out over the yard. The apple trees were filled with ripe, red apples.
As he sat there thinking, he noticed an apple falling from the tree. Apples fall from trees all the time. They even fall and hit people on the head. But Isaac Newton's falling apple was no ordinary apple. And Newton was no ordinary man.
He saw more than an apple falling from a tree. As he watched the apple hit the ground, he asked himself some simple questions: Why did that apple fall straight down? Why did it not fall sideways? Why did it not fall up, towards the sky, instead of down, towards the centre of the earth?
With these simple questions,Newton discovered gravity.More correctly, he discovered how gravity works.
Scientists could now understand why the moon was held in orbit around the earth.Gravity explained why people did not fall off the face of the earth.
Imagine if Newton had watched that apple falling, and thought nothing more than,"Oh yes, just another apple falling from a tree!"