"Everything that can be invented has been invented."
Charles H. Duell, Commissioner, U.S. Office of Patents, 1899.
The term modern physics often finds students raising an eyebrow as they read about experiments and discoveries that were successfully completed more than hundred years ago. The term was coined by physicists who saw in the work of Thomson and Rutherford, of Planck and Einstein, and a host of others, a new physics significantly different from the classical mechanics of Newton, the electrodynamics of Maxwell, or the conception of the atom espoused by Dalton.
What you will encounter at this site is an extended history outlining the arguments to support the existence of atoms. Following that comes descriptions of what are called in physics "classic experiments" the results of which lend themselves to the modern explanation of how nature seems to work.
At the end of this unit the student should have firm understanding of how we know what we know about the parts of the atom. Please remember two points: 1) Text books tell of only the success stories. Failed experiments, dead ends, time and resources wasted are never mentioned here. 2) Every new discovery represents a refinement of our view of nature. None of these discoveries should be considered as an ultimate truth, never to be refined again.
For a cursory overview of this period find the time line at
For a good collection of lectures on the topics listed below, go to
A fairly basic look at the atom from University of Colorado
A. Early evidence of atomic structure
B. J.J.Thomson - the Electron
C. Millikan oil drop experiment
D. Rutherford/ Bohr - the Nuclear atom
E. The Photoelectric Effect
F. Matter waves
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Click here I to find a list of people who have made a significant contribution to our understanding of the atom and its outer structure. On the instructor's door is a sign-up sheet. Select one of the persons listed and prepare a biographical profile of your physicist. Along the way, in addition to relating what he/she did for science, describe any pertinent details about his/her private, non-science life that may give you a sense of the people-issues surrounding their work. This paper should be a minimum two pages in length and should be written according to the style approved by the English department.
References - For useful references regarding this topic, go to REFERENCES.
Last edited 12/26/05
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