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5 December 2013 11:26 am ,
Vol. 342 ,
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Master of the Atomic Shell Game
7 October 1999 7:00 pm
Today is the birthday of Niels Bohr, a Danish physicist born in 1885, who elucidated the structure of the atom and explained the process of nuclear fission. Working with Ernest Rutherford to investigate the structure of the atom, Bohr developed a model of the atom in which electrons existed in shells around the nucleus. He then added Max Planck's quantum theory--that radiation is emitted or absorbed by atoms in discrete units or quanta of energy--to the picture.
In 1913, Bohr proposed that an atom can only exist in a certain number of stable states, each with a particular amount of energy, and that an atom will absorb or emit energy when an electron moves from one shell--or energy state--to another. By reconciling Rutherford's and Planck's views, Bohr produced a new and insightful model of the atom. Bohr's vision of the atomic nucleus, as particles weakly held together, led to his explanation of why some elements are prone to break apart by fission. Bohr received the Nobel Prize in physics in 1922.