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10 April 2014 11:44 am ,
Vol. 344 ,
Tight budgets are forcing NASA to consider turning off one or more planetary science projects that have completed their...
Ebola is not a stranger to West Africa—an outbreak in the 1990s killed chimpanzees and sickened one researcher. But the...
In an as-yet-unpublished report, an international panel of geoscientists has concluded that a pair of deadly...
Tropical disease experts tried and failed before to eradicate yaws, a rare disfiguring disease of poor countries. Now,...
Since 2002, researchers have reported that agricultural communities in the hot and humid Pacific Coast of Central...
Balkan endemic kidney disease surfaced in the 1950s and for decades defied attempts to finger the cause. It occurred...
The Pyrenean ibex, an impressive mountain goat that lived in the central Pyrenees in Spain, went extinct in 2000. But a...
- 10 April 2014 11:44 am , Vol. 344 , #6180
- About Us
23 March 1998 7:00 pm
Yesterday was the birthday of Robert Millikan (born in 1868), the physicist who first measured the charge of an electron--an experiment repeated every year by physics students around the world. In 1908, physicists were struggling to measure the electron's charge with clouds of water droplets. By placing a charge on the droplets, they could tug the droplets upward against gravity with an electric field. Once the droplets were hovering in midair, their mass and the strength of the electric field would reveal the charge of the electron. But evaporation was foiling the measurements, so Millikan substituted oil droplets. His experiment succeeded, and Millikan proved that the electron was indeed an elementary particle with a fundamental charge. He published his value for the charge of an electron in 1913 and 10 years later received the Nobel Prize in physics.
[Source: Emily McMurray, Ed., Notable Twentieth Century Scientists (Gale Research Inc., ITP, 1995).]