"It followed from the special theory of
relativity that mass and energy are both but different manifestations of the same thing --
a somewhat unfamilar conception for the average mind. Furthermore, the equation E is equal
to m c-squared, in which energy is put equal to mass, multiplied by the square of the velocity
of light, showed that very small amounts of mass may be converted into a very large amount of
energy and vice versa. The mass and energy were in fact equivalent, according to the formula
mentioned before. This was demonstrated by Cockcroft and Walton in 1932, experimentally."
From the soundtrack of the film, Atomic Physics
copyright © J. Arthur Rank Organization, Ltd., 1948.
Image © Brown Brothers, Sterling, PA