The discovery of nuclear fission was one of the most dramatic scientific breakthroughs of the 20th century. Within a few years, the fantastic energy latent in the nuclei of atoms would be powering reactors and bombs, a development that fundamentally changed the relationship between physics and human affairs. To drive home the magnitude of this energy, authors of popular articles and books often present some superlative statistic such as how far you could drive your automobile with the energy available in a kilogram of uranium. Another example often quoted is that the energy released in the fission of a single nucleus of uranium is sufficient to make a grain of sand visibly jump. This image has an appealing simplicity, but is it true? This brief article investigates the issue.

1.
G.
DeGroot
,
The Bomb: A Life
(
Harvard University Press
,
Cambridge, MA
,
2004
), p.
16
.
2.
The visual acuity of the eye is usually taken to be about one minute of arc
. See https://en.wikipedia.org/wiki/Visual_acuity.
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