On Christmas Day 1642, a farmer's wife gave birth to a baby boy in Lincolnshire, England. Isaac Newton was a sickly child who found it difficult to make friends. When it came to farming, he got into trouble for letting the pigs go astray and the fences fall down. But he was fascinated by inventions, spending his time carving sundials and making kites. No one would have guessed that, when Newton grew up, he would be one the the greatest scientists the world has ever known. His discoveries would change the way people understood the universe.