Joseph Fourier was born on March 21, 1768 in Auxerre, France and died in Paris on May 16, 1830. He had eleven brothers and sisters. Fourier was a very good student and did well in French, Latin and literature; however, by the time he became thirteen years old he decided that his favorite subject was mathematics. In 1787 he entered a Benedictine abbey to learn to become a priest. He never took the vows of a priest because he struggled between becoming a priest or spending his life studying mathematics. He decided to study math because he really wanted to do something very important in math. He eventually became a teacher and taught at the Ecole Polytechnique in Paris from 1795 to 1798. 

He took a break from his math studies to become involved in the French Revolution. He helped Napoleon in his invasion of Egypt as a scientific adviser. Also, he helped to set up learning facilities in Egypt, set up the Cairo Institute and he did some archaeological explorations. In 1801 he returned to France and began teaching again and doing mathematical research. 

One of the areas that Fourier did mathematical research on was heat. He published a paper called The Analytical Theory of Heat in 1822. The research in this paper is usually called the Fourier series. It shows that "periodic functions can be expressed as the sum of an infinite series of sines and cosines."

Fourier also did research with muscial sounds. He proved that all musical sounds, which have 3 components (pitch, loudness, and quality), can be shown by a mathematical expression. This paved the way for others to graphically represent these properties.

Fourier’s theories are used to study actions that repeat many times. Here are some examples where you can see Fourier’s work with numbers used in our everyday life: