•---1900-1915

__Henri Becquerel1903__ Henri Becquerel was born December 15, 1852 in Paris and later he passed away August 25, 1908. Becquerel was part of a family full of scientists and scholars. His father was a physics professor and did research on raiation. His grandfather was a member of the Royal Society and an inventor of an elerolytic method for removing metals from their ores. Becquerel received his scientific education at the Ecole Polytechnique and engineering training at the Ecole des Pontes et Chaussess which was a bridge and highway school. He was appointed chief engineer in 1894 of the department of bridges and Highways. In 1876 he earned his first teaching job at Ecole Polytechnique. This picture from [] He was interested in the newly discovered X-rays and he thought that they were emitted in conjunction with phosporesence. His experiments involved him putting crystals composed of potassium uranyl sulfate on top of the photogenic plate wrapped in a black cloth. Then he put the wrapped plate and crystals outside to give it exposure to the sunlight. When he brought it back inside he could see a green glow. He also did this experiment in the dark and got the same result. He then realized that the uranium crystals themselves caused the emmision which he called uranic rays.

__Robert Millikan 1909__ Robert Millikan was born March 22, 1868 in Morrison Illinois United States and died in 1953. During World War I Millikan was vice chairman of the National Research council which was vital to the development of the anti submarine and also meterological devices. His grandparents were part of the Old New England Stock who came to America before 1750, and they were the pioneer settlers in the Middle West. In 1886 he went to Oberlin College in Ohio. His favorite subjects were mathematics and Greek. After he graduated he taught for two years in elementary physics. He later received his Ph.D. in 1895 for research on the polarization of light emmitted by incadescent surfaces. He also spent a year in Germany at the Universities of Berlin and Gottingen. This picture from [] At the University of Chicago he discovered the unit charge of the electron. He discovered this by performing an oil drop experiment. What he did was put a charge on a tiny drop of oil, and measured how strong the electron field had to be in order to stop the oil drop from falling. This oil drop experiment confirmed that the electron existed. What he basically did was release a cloud of droplets into a chamber, then he used charged plates to suspend the droplets against gravity. From this he was able to calculate the charge of an electron.

__Marie Curie 1911__ Marie Curie was born in Warsaw in 1867 and died in 1934. Curie received a general education in local schools and she also had some scientific experiments with her father. She was involved in the student's revolutionist organazation and she had to leave Warsaw. In 1881 she went to Paris and studied at Sorbonne. She got her degrees in Physics and Mathematical sciences. In 1903, she gained her doctrine of science degree. She was introduced to the use of radium during World War I where she worked as an X-ray technisian. Marie Curie and her husband led to the use of radioactive materials in medicine. They were able to isolate radium. She was the first women to win two noble peace prize for two different subjects. She discovered that all radioactive substances come from the atom itself. This was revolutionary and her hypothesis that radiation was an atomic property changed the war people looked at an atom. This picture from []