Robert Millikan - 1897

video
Born: born and raised in Illinois 
EducationMaquoketa High School, Oberlin College, then discovered passion for Greek and mathematics. 
  • Then worked teaching elementary physics - ended up loving. 
  • Received masters in physics then got Ph.D. for research of polarization of light emitted by incandescent surfaces.
Biggest accomplishment in life?
  • Made it possible to measure the charge of an electron.
·    How?
  •       The Oil Drop Experiment:
An atomizer sprayed a fine mist of oil droplets into the chamber. Some of these tiny droplets fell through a hole in the upper floor. Millikan first let them fall until they reached terminal velocity. Using the microscope, he measured their terminal velocity, and by use of a formula, calculated the mass of each oil drop.
Next, Millikan applied a charge to the falling drops by illuminating the bottom chamber with x-rays. This caused the air to become ionized, and electrons to attach themselves to the oil drops.
By attaching a battery to the plates above and below this bottom chamber, he was able to apply an electric voltage. The electric field produced in the bottom chamber by this voltage would act on the charged oil drops; if the voltage was just right, the electromagnetic force would just balance the force of gravity on a drop, and the drop would hang suspended in mid-air. (The Oil Drop Experiment).
·         Other accomplishments:
o   Verified Einstein’s photoelectric equation
o   Made the first direct photoelectric determination of Planck's constant h
o   His studies of the Brownian movements in gases put an end to all opposition to the atomic and kinetic theories of matter
o   The hot-spark spectroscopy of the elements (which explored the region of the spectrum between the ultraviolet and X-radiation), thereby extending the ultraviolet spectrum downwards far beyond the then known limit
o   The discovery of his law of motion of a particle falling towards the earth after entering the earth's atmosphere, together with his other investigations on electrical phenomena, ultimately led him to his significant studies of cosmic radiation
o   During WWI, played a major part in developing anti-submarine and meteorological devices

  • Enjoyed mushing together religion and science with his books (Science and Life(1924); Evolution in Science and Religion (1927), ect)
  • Millikan was an enthusiastic tennis player, and golf was also one of his recreations