Model of Fresnel Refraction by Richard P. Baker, Baker #378

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Richard P. Baker, a mathematician at the University of Iowa, made a series of models relating to the relative intensity of polarized light transmitted by an isotropic medium. In all of them, the ratio of the magnitude of two electromagnetic vectors is plotted extending vertically, as a function of the index of refraction of the medium and the angle of incidence of the light. In Baker’s scheme, the vectors Ds, Es, and Rs lie in the surface between the two media, while the vectors Dp, Ep, and Rp lie in the plane of polarization. The E vectors represent the electric force, the R vectors the reflected wave, and the D vectors the refracted wave. This particular model plots values of the ratio of intensities Dp / Ep, a function equal to 2 cos θ sin φ / sin (θ + φ). Here θ is the angle of incidence of the light and φ is the angle of refraction.
The model has a wooden base and sides, with a plaster top. A typed paper tag attached to the base reads: No. 378 (/) 10 Freshnel [sic] surfaces. A paper label on the bottom, marked in ink, reads: No.378 (/) Refraction (/) Electric Vector (/) Dp / Ep.
Baker associated this model with “Drude’s Electric Vector.”
Accession File.
R. P. Baker, Mathematical Models, Iowa City, Iowa, 1931, p. 18.
Paul Drude, with C. Riborg Mann and Robert A. Millikan, translators, Theory of Optics, New York: Longmans, Green and Co., 1902, esp. pp. 279-280.
Currently not on view
date made
ca 1906-1935
Baker, Richard P.
Physical Description
plaster (overall material)
wood (overall material)
white (overall color)
black (overall color)
plaster cast,bolted to base. (overall production method/technique)
average spatial: 7.2 cm x 15 cm x 15 cm; 2 27/32 in x 5 29/32 in x 5 29/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Frances E. Baker
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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