Born as Galileo Galilei, on February 15, 1564 in Pisa, Italy, Galileo invented even as a child. When he was a child, he used items found around his home and put them together to make small mechanical toys. I think that this influenced his later life, because this was like practice for inventing. All of these toys worked, and he probably learned to keep at it, because he must have made mistakes. Inventing is similar to this, because you have try out many designs before any of your inventions can work.
As a 10-year-old, he attended school at Vallembrosa. He got good grades, and as he grew up, his father, Vincenzio Galilei, decided Galileo should become a doctor. Galileo did not want to do this, but did as he was told. In 1581, Galileo entered the University of Pisa. However, his study of medicine was not interesting to him, and his grades were not good. He began to study mathematics instead. Like his father, Galileo liked mathematics, and preferred it to medicine.
During his first year at the university, Galileo made his first important discovery. He discovered the law of the pendulum. The law says that no matter how long the length of the string is, the time of the swing will stay the same. With his new discovery, Galileo invented the pulsilogia, which measures a person's pulse. Because of his low grades, Galileo's father took him out of the university in 1585.
Soon after leaving the university, Galileo invented the hydrostatic balance. This could weigh objects in water and then, their density could be figured out. Galileo wrote a paper about this scale in 1586. The Marchese Guidobaldo del Monte became interested in Galileo's studies, and the two became friends. The Marchese was wealthy and gave Galileo money to fund his experiments.
By now, Galileo began to look for a job. The University of Bologna had a mathematics professor position open, but Galileo was not hired. At his old university, there was a position open, and this time, Galileo was hired. His job only lasted for two years, and again Galileo had to look for a job. But in 1592, his luck changed. He was hired at the University of Padua, one of the best universities at that time. He was an appreciated teacher, and was now married to a woman named Marina Gamba. He was now free to experiment and invent. During that time, he built himself a geometrical compass, and invented the first thermometer.