Final answer:
The electric charge of an electron has been measured in various media, most notably in Robert Millikan's oil drop experiment, where he calculated the charge on a single electron by adjusting electric field strength. Millikan's experiment demonstrated that all charges were multiples of the basic electron charge.
Step-by-step explanation:
The electric charge of an electron has been measured in various media, most notably in Robert Millikan's oil drop experiment. Millikan created electrically charged oil droplets and calculated the charge on a single electron by adjusting the electric field strength and making careful measurements.
By 1913, Millikan had measured the charge of the electron to an accuracy of 1%, and his experiment demonstrated that all charges were multiples of the basic electron charge.