University of Colorado
University of Colorado: Physics 2000: Spectral Lines
Several pages from an excellent site which describe the science of spectroscopy. The unique atomic emission (and absorption) line spectrum of elements are illustrated and explained. Includes a Java applet depicting the quantum energy...
PBS
Pbs: People & Discoveries Niels Bohr
A wonderful PBS biography of a great man. This contains many personal touches, yet does a fine job of describing Bohr's scientific work. But it's best at Bohr the man. Nice quotes, one in the middle, one at the end.
PBS
Pbs: Planck Discovers the Quantum Nature of Energy
PBS offers a short summary of the discovery of the quantum nature of the atom by Max Planck. Easy to follow.
Georgia State University
Georgia State University: Hyper Physics: Photoelectric Effect
Using graphics, words and numbers, the photoelectric effect is described and explained. Planck's theory about quanta of light is explained. Photon energies for the various regions of the EM spectrum are listed. An interactive JavaScript...
University of Maryland
University of Maryland: Optics, Electromagnetic Waves
This site from the University of Maryland provides part of an anecdotal history of optics and the study of light. Extremely thorough treatment of how scientists came to believe in the wave nature of light, the idea of an electromagnetic...
McGraw Hill
Mc Graw Hill Companies: Origins of the Quantum Theory
An indexing page for Chapter 27 (Origins of the Quantum Theory) of the companion web site for McGraw Hill's Contemporary College Physics textbook. Includes several worthy pages with chapter notes, simple definitions, online computer...