Francis Bitter (July 22, 1902 - July 26, 1967) was an American physicist.

Bitter invented the bitter plate used in resistive magnets (also called bitter electromagnets. ) He is the one who thought of using dust to visualize a magnetic field. (Many grade school children put metal filings on a paper with a magnet underneath to help visualize magnetic field lines.) He built the bitter electromagnet by using stacked copper plates, rather than coiled wire. Previous to this time there was no way to cool the magnets so their power was limited.

Dr. Bitter was born in the Weehawken Township, New Jersey. He studied at Columbia University graduating in 1924. He continued his studies in Berlin from 1925-26 in physics and received a Ph.D. at Columbia in 1929. He is a 3rd generation Ph.D. from Hermann von Helmholtz who had 9 Nobel Prize winners in his academic progeny. Robert C. Richardson , one of Francis' students received the Nobel prize in physics in 1996.

His main contribution focuses on the magnetic properties of matter. He studied gases at Caltech with Robert Andrews Millikan, worked on various theoretical and applied problems at Westinghouse Electric and Manufacturing Company in Pittsburgh. In 1934 he joined the faculty at the Massachusetts Institute of Technology where he developed the bitter electromagnet which was/is the most powerful electromagnet design. The MIT National Magnet Laboratory in Boston is named in his honor. He also did work in the first characterization of the zeeman effect.