- News Home
12 December 2013 1:00 pm ,
Vol. 342 ,
The iconic 125-year-old Lick Observatory on Mount Hamilton near San Jose, California, is facing the threat of closure...
Recent results from the Curiosity Mars rover have helped scientists formulate a plan for the next phase of its mission...
A new, remarkably powerful drug that cripples the hepatitis C virus (HCV) came to market last week, but it sells for $...
In pretoothbrush populations, gumlines would often be marred by a thick, visible crust of calcium phosphate, food...
Evolutionary biologists have long studied how the Mexican tetra, a drab fish that lives in rivers and creeks but has...
Victorian astronomers spent countless hours laboriously charting the positions of stars in the sky. Such sky mapping,...
In an ambitious project to study 1000 years of sickness and health, researchers are excavating the graveyard of the now...
Stefan Behnisch has won awards for designing science labs and other buildings that are smart, sustainable, and...
- 12 December 2013 1:00 pm , Vol. 342 , #6164
- About Us
Master of the Atomic Shell Game
7 October 1997 8:00 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.