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how things moved. Using his laws of motion, he could solve a range of problems, from the time it takes for a falling apple to hit the ground to the motion of the moon. Newton’s laws were highly accurate in almost all cases. However, in the nineteenth century, new discoveries were made that could not be fully explained by Newton’s laws. Ludwig Boltzmann (1844–1906) developed a new theory of heat that made it possible to calculate how a gas would behave when heated. This could be used to make steam engines more efficient. The laws of electricity and the properties of magnets were discovered by James Clerk Maxwell (1831–79), leading to the development of electric motors. These laws enabled physicists to better understand what light is. Again, as the nineteenth century drew to a close, there was a feeling among scientists that man really understood how nature works. But again, this was not so. As new experiments were carried out, new results were found that did not work with the existing theories. At first, some scientists thought that minor changes to the mathematical formulas would resolve the problems. As the failures of the old theories increased, however, it became clear that this was not so. What was needed was a change in the way people thought about the problems. The new theories would be very different from the ideas of the previous four centuries. Many scientists would contribute to a changing understanding of how the world works in the first three decades of the twentieth century. None of them contributed more of lasting value than Albert Einstein. Einstein’s Early Life Albert Einstein was born on March 14, 1879, in Ulm, a small town in southern Germany. Albert’s mother, Pauline, to whom he was always deeply attached, came from a family of moderate wealth. Two years before he was born, they had helped Hermann Einstein, Albert’s father, to set up a small engineering workshop. They helped again when the business failed a year after Albert’s birth, and the family moved to nearby Munich. Hermann Einstein was a jovial, well-meaning man, but he was not serious enough to make a success of his business. However, with the aid of his wife’s relations, he was able to provide a comfortable home for his wife, his son, and his daughter Maja, born two years after Albert.

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