Galileo Galilei (Feb. 15, 1564 -- Jan. 8, 1642) was an Italian physicist, astronomer, and mathematician who is widely considered to be the father of modern science, in which ideas about the world are only considered true after experiments are in agreement with them. Galileo is credited with first observing that falling bodies of different masses move the same through gravity, contradicting popular conceptions of the day. He proposed a heliocentric model of the Solar System to explain the observed motion of the planets.
Nikola Tesla (July 10, 1856 -- Jan. 7, 1943) was an American-Serbian physicist who made contributions to the study of electricity which were far ahead of his time. A man with a troubled social life, he never completed his program while at Austrian Polytechnic. After coming to America, he worked briefly for Thomas Edison, leaving after feeling his talents were unappreciated. Edison and Tesla continued to feud for the remainder of their lives. Tesla was an integral mind in the development of AC power (currently used in households around the world).
Maria Goeppert-Mayer (June 28,1906 -- Feb. 20, 1972) was a German-born American theoretical physicist, doing work in modeling the behavior of the atomic nucleus. Goeppert-Mayer attended the University of Gottingen, receiving her PhD and marrying her husband, a lab assistant of her graduate advisor in 1930. Due to sexism, she was unable to find steady full-time work in a University. While working part time in Argonne National Laboratory, she developed a mathematical model of atomic nuclei, which gave explanation to an otherwise not well understood phenomenon of stability within atoms.
Born in Cresco, Iowa (March 25, 1914 -- Sept. 12, 2009), Norman Borlaug was an agricultural researcher, plant pathologist, and plant geneticist. After receiving his doctorate at the University of Minnesota, Borlaug developed genetic varieties of wheat which are highly disease-resistant and are of especially high yield. His work led to staggering increases in the production of agricultural products which, by some estimations, has saved upwards of a billion people who would otherwise die of starvation. He won a Nobel Peace Prize in 1970 for his contributions to humanity.