James Franck was a physicist whose experimental work with atoms and electrons proved Niels Bohr's theory that atoms are quantized--that they transmit and absorb energy in discrete quantities or packages. Along with collaborator Gustav Hertz , he was awarded the 1925 Nobel Prize in physics. Franck was also known for his outspoken opposition to the use of the atomic bomb, which he helped develop during World War II.

Franck was born in Hamburg, Germany, on August 26, 1882, to Jacob Franck, a German Jewish banker, and Rebecka Nachum Drucker. Although Jacob Franck was deeply religious--he observed Jewish holidays with fasting chanting--his spiritual devotion did not, on the whole, pass on to James, who would later declare science and nature as his true love and religion. He attended school at the Wilhelm Gymnasium in Hamburg before enrolling at the University of Heidelberg. Franck's father wanted him to study law and economics with the...