Robert Milikan

Electron Charge

• charge-to-mass ration of electrons was discovered
• the actual values were unknown though
• Milikan and grad student figured actual values
• results of oil drop are integer multiples of this…
• 1.592x10^-19 coulom 

Electron Charge

• calculated charge carried by electron using falling drop method
• used oil drop experiment to measure force on droplets
• knowing electric field- charge can be solved  

Electron CHarge

• proved charge quantity is constant 
• demonstrates atomic structure of electricity

Background

• Grew up in Iowa, bachelors from oberlin college 
• PhD from Columbia university
• Professor and wrote several textbooks
• He had three sons, died at 85 in CA
• Vice Chairman of national research council during WW1