

A matrix is simply an array of numbers. 



In 1922, Heisenberg was 20 years
old and still working on his PhD. He attended one of Bohr's
lectures and rose at the end to object to a point Bohr had
made. Bohr was so impressed that he invited Heisenberg to
walk in the mountains after the lecture. Bohr confided that
he was deeply worried about the ad hoc state of quantum
mechanics. Heisenberg loathed Bohr's atomic models and set
to work to develop an alternate theory more to his liking.
He immediately discarded Bohr's solar system model as he
disliked the classical idea of orbits being applied to the
atomic scale. He developed a description of quantum mechanics
based on mathematical objects called matrices – simply
arrays of numbers.
Heisenberg's matrix description of quantum mechanics
was not at all popular as it was so abstract and hard
to visualize. There were no visual aids, like Bohr's orbits
to fall back on. Despite this, Heisenberg is generally
regarded as the father of quantum mechanics and he won
the 1932 Nobel Prize in physics for his outstanding contributions. 