History 181B - Class 13

History 181B: Modern Physics

Class 13 (2/19/03)
New radiations, new phenomena (1)
(There is no Class 12.)

Navigation

Home

Schedule

< Previous Class

Next Class >

Outline

Experimenting with cathode ray tubes
How they work (relatively simple)
What you see (relatively complicated)

X-rays (1895)
    Experimenting around the CRT
    What are these new rays? EM or not, what sort of EM
    X-rays as a tool: Radiography, crystal structure

Radioactivity (1896)
    Becquerel: From phosphorescence via x-rays to uranium
    What are these new rays? Particles or EM
    Where do they come from?
        Chemical isolation
        New radioactive elements
    What is going on?
        What is the source of the energy?
        Messy chemistry: More than one radioactive source
        The explanation: Transmutation (1902)
        Radioactive decay: A statistical process

Names and terms

Primary

Secondary

CRT, Geissler tube, Crookes tube, gas discharge tube
phosphorescence
Wilhelm Conrad Röntgen (1845-1923), NP 1901
uranium (chemical symbol: U)
Henri Becquerel (1852-1908), NP 1903
alpha, beta, gamma radiation
Pierre Curie (1859-1906), NP 1903
Marie Curie (1867-1934), NP 1903, NP Chemistry 1911
polonium (Po), radium (Ra)
Ernest Rutherford (1871-1937), NP Chemistry 1908
Frederick Soddy (1877-1957), NP 1921
transmutation, decay
decay series
half-life

cathode, cathode ray, gas discharge
Max von Laue (1879-1960), NP 1914
William Henry Bragg (1862-1942), NP 1915
William Lawrence Bragg (1890-1971), NP 1915
fluorescence
N = N₀ exp (-t/t₀)

Assignment

W.C. Röntgen, "On a New Kind of Rays," Nature 53 (1896): 274-276, also on the web .

    Röntgen's new phenomenon is identified already in the first paragraph of this report. What is the point of the following paragraphs on the first page?
    And in the rest of the paper? (What question was Röntgen trying to answer?)
    What conclusion did Röntgen end up drawing about the nature of the rays?

AND

Marie Curie, "Radium and Radioactivity" (1904), on the web .
"Marie Curie and the Science of Radioactivity," on the web .

    After the 1904 article, read through the chapters of the main exhibit (just use the "Next" links) through "The Radium Institute" (i.e., you can stop before "The next generation of Curies"). The side links are optional.
    By what route did Curie end up working on radioactivity? Why did she pick up the topic? What did she expect to find?
    What lab equipment and procedures were needed? What other sorts of infrastructure?
    For what did she receive each of her Nobel Prizes?
    Besides knowing more about Curie herself, what do you learn from the personal details?
    And what from the information about her efforts to raise money and build institutes?