University of Maryland - Spring 2005
HIST 402
Study Questions for Topic 5

See instructions for Topic 1 Study Questions.

1. Identify: Marie Curie.
2. For many years it was believed that transmutation of one element into another was just a fantasy of the alchemists and could never be observed in the laboratory. Who were the two scientists who first demonstrated that it actually occurs? When did they do it?
3. What was the experiment that revealed to Rutherford that the atom is mostly empty space with most of its mass concentrated in a tiny nucleus at the center? Who did the experiment?
4. Identify: Louis de Broglie.
5. Discuss the introduction of the concepts of randomness, probability, and indeterminism into science, and how they changed our understanding of the world.
6. What is "wave mechanics"? Who proposed it? When?
7. What was the Einstein-Podolsky-Rosen (EPR) objection to quantum mechanics. How was it refuted by Aspect's experiment?
8. Discuss the statement "every time you take a breath of air, you swallow one of the molecules that came from Julius Caesar's last breath" from the viewpoint of quantum mechanics.
9. How did Heitler and London explain (qualitatively) why atoms form molecules?
10. Discuss X-rays and their connections with modern physics, chemistry, biology, and fin de siècle society.
11. Identify: Satyendranath Bose.
12. What is Heisenberg's "Uncertainty Principle"? Why might it be more properly called an "Indeterminacy Principle"?
13. What was Dirac's idea that was so outrageous it almost had to be right? How was it confirmed?
14. Why was Schrödinger's wave equation considered inadequate from the viewpoint of relativity theory?
15. According to a frequently-told story, when someone asked Ernest Rutherford how he always managed to be on top of the wave of progress in physics, he replied: "because I make the wave!" Discuss the validity of this claim.
16. Explain (using diagrams) how a positron can be considered an electron moving backward in time.
17. Identify: Feynman diagram.
18. Define "radioactive half life." What is the implication of this concept for the validity of the Newtonian paradigm?
19. How did the discoveries of Marie Curie and Ernest Rutherford undermine, in two ways, Lord Kelvin's estimate of the age of the Earth?
20. Describe Bohr's 1913 model of the hydrogen atom. How was it similar to Newton's model of the solar system? How was it different? Why was it (temporarily) accepted despite its obvious defects?
21. How did the discovery of radioactivity support the credibility of Darwin's theory of evolution?
22. Explain the difference between atomic weight and atomic number, on the basis of the theories of Rutherford and Heisenberg.
23. Identify: H. G. J. Moseley.
24. Identify: Joseph Fraunhofer.
25. Discuss the history of quantum theory from 1900 to 1935, including the major ideas and experiments, the relevant facts from 19th century physics and chemistry, and philosophical issues about its interpretation.
26. How did Kirchhoff explain the fact that the bright emission line of sodium vapor has the same wavelength as a particular dark line (actually a pair of lines very close together) in the solar spectrum?
27. How dd Kirchhoff's 1859 discovery allow scientists to refute a notorious statement published almost 30 years earlier by Auguste Comte?
28. Identify: "Doppler effect." How was it first confirmed?
29. Identify: J. J. Balmer.
30. How did Bohr, Born, Heisenberg and Schrödinger change our understanding of the world? Is there a real distinction between "the world" and "our understanding" of it? Your essay should include (but not be limited to) Cartesian and wave-particle dualisms, indeterminism, the Copenhagen Interpretation, and the cat paradox.
31. According to Karl Popper, in order to be "scientific" a theory must make testable predictions. Was Balmer's theory of the hydrogen spectrum scientific? What was his theory?
32. How did Niels Bohr, in his 1913 theory of the hydrogen atom, deal with the objection that according to Maxwell's electromagnetic theory, an charged electron moving in a curved path around a charged nucleus must radiate energy, so its orbit could not be stable?
33. Who predicted the "Bose-Einstein condensation"? Who confirmed it, and how?
34. What is Balmer's formula for the frequency (1/λ, inverse of wavelength) of lines in the hydrogen spectrum? What do the numbers n' and n" in that formula correspond to, according to Bohr's theory?
35. Does a scientific theory have to explain all the known facts in its domain in order to be considered valid? Discuss the history of two theories (or laws), one in physics and one in chemistry, each of which was widely accepted by scientists before there was a plausible explanation of why its basic assumptions should themselves be valid.
36. What is Pauli's exclusion principle? How does it help to explain the chemical properties of the elements?
37. Identify: Erwin Schrödinger.
38. Explain Schrödinger's "cat paradox." What point was he trying to make?
39. [no question]
40. Discuss the following statement of Dirac on the basis of your knowledge of the history of science: "It is more important to have beauty in one's equations than to have them fit experiment. ... It seems that if one is working from the point of view of getting beauty in one's equations, and if one has a really good insight, then one is on a sure line of progress. If there is not complete agreement between the results of one's work and experiment, one should not allow oneself to be too discouraged, because the discrepancy may well be due to minor features that are not properly taken into account and that will get cleared up with further developments of the theory."

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