<<1900-1915>>

Marie Curie was born November 7, 1867 in Warsaw, Poland, and died on July 4, 1934 in Haute Savoie. She studied radioactivity, and discovered polonium and radium. Marie Curie was also the first person to win two Nobel prizes. Her radium was a key to a basic change in our understanding of matter and energy. Marie was and still remains as the world’s most famous woman scientist.

Robert Andrews Millikan was born on March 22 1868, in Morrison ILL. He did not discover his intrest for science until teaching physics at an elementary school. He soon excelled, and made numerous momentous discoveries, chiefly in the fields of electricity, optics and molecular physics. One of his earliest major discovery was the charge carried by an electron, he did this by using the falling drop method. He proved with this that it was a constant for all electrons. Also by experiment he verified Einsteins photoelectric equation, and mad the first direct photoelectric determination of Planck’s constant h. His studies of the Brownian movements in gases put an end to all oppostion to the atomic and kinetic theories of matter Ernest Rutherford was awarded the 1908 Nobel Prize in chemistry for his investigations into the disintegration of the elements, and the chemistry of radioactive substances. He was one of the founders of nuclear physics. In 1894 he developed a detector for radio waves which depended on the magnetization of iron. Rutherford with the help by Soddy realized that radioactive atoms change spontaneously to other atoms, and had defined the idea of isotopes. Rutherford determined the ratio of electric charge to mass of he alpha practice. The deflection of the particles in the electric field, and the required ration was obtained from the magnitudes of these deflections. In 1911 he proposed his most revolutionary idea, concerning the existence of the atomic nucleus. He lived from 1871-1937.





Niels Bohr was born in Copenhagen on October 7, 1885. He was born into an educated family and started young. In 1911 he worked with Ernest Rutherford. Bohr then began to work on the structure of the atom on the basis of Rutherford’s discovery of the atomic nucleus. He succeeded in working out and presenting a picture of atomic structure that, with later improvements. He also contributed to the clarification of the problems encountered in quantum physics, in particular by developing the concept of complementarity. He received the Nobel Prize in Physics in 1922.