school to graduate there in 1900 with a degree in
teaching. Unable to find a university position, Einstein
accepted a job at the Swiss Patent Office in Bern in
1902 and remained there for 7 years.
During his time at the patent office, Einstein stud-
ied theoretical physics in the evenings, without the ben-
efit of close contact with the scientific literature or
colleagues, and managed to produce and publish, all in
the year 1905, five truly outstanding papers:
• “Über einen die Erzeugung und Verwandlung des
Lichtes betreffenden heuristischen Gesichtspunkt”
(On a heuristic concerning the production and trans-
formation of light), published in Annalen der Physik,
March 1905.
• “Die von der molekularkinetischen Theorie der
Wärme gefurdete Bewegung von in ruhenden Flüs-
sigkeiten suspendierten Teilchen” (On the movement
of small particles suspended in a stationary liquid
demanded by the molecular kinetic theory of heat),
published in Annalen der Physik, May 1905.
• “Zur Elektrodynamik bewegter Körper” (On the
electrodynamics of moving bodies), published in
Annalen der Physik, June 1905.
• “Ist die Trägheit eines Körpes von seinem Energiein-
halt abhängig?” (Does the inertia of a body depend
upon its energy-content?), published in Annalen der
Physik, September 1905.
• “Eine neue Bestimmung der Moleküldimensionen”
(A new determination of molecular dimension), writ-
ten in April 1905, published in Annalen der Physik,
April 1906.
The first paper was concerned with the puzzling
photoelectric effect observed by scientists of the time.
Heinrich Hertz (1857–94) noticed that the number of
electrons released from a section of metal bombarded
with a beam of light was determined not by the inten-
sity of the beam, but rather by its wavelength. Max
Planck (1858–1947) also observed that electromagnetic
energy was emitted from radiating objects according to
discrete quantities, again in direct proportion to the
wavelength of the radiation. Einstein proposed that
light and radiation itself travel in discrete bundles,
which he called quanta, and described the mathematics
that would consequently explain these phenomena.
In his second paper, Einstein developed mathemati-
cal equations that correctly described the motion of
atoms and molecules under “Brownian motion.” In his
third paper, Einstein proposed his theory of special rela-
tivity. He noted that because light is able to travel
through a vacuum, there is no natural frame of refer-
ence for measuring its speed. (The speed of sound, for
instance, is measured with respect to the medium of air
through which it passes.) Also, since it is impossible to
determine whether one is stationary in space or moving
through space at a uniform velocity, it follows then that
all observers must observe light traveling at the same
speed. From this, Einstein developed a series of
“thought experiments” that clearly establish that
observers traveling at different speeds must hence
record different values when measuring quantities such
as length and time. (For instance, imagine a light beam
bouncing back and forth between two fixed mirrors set
at a distance so that the time taken to bounce between
the two mirrors is 1 sec. Suppose that a second observer
moves past the “clock” with uniform speed. According
to this observer, the clock moves past her at uniform
speed. A straightforward calculation shows that, since
the speed of light is unchanged for this observer, she
would see the light beam taking longer than 1 sec to
complete a cycle between the two mirrors.) The fourth
paper developed the special theory of relativity further,
culminating with his famous equation E= mc2, show-
ing that energy and mass are equivalent (with a factor
of the speed of light squared incorporated).
Einstein submitted his final paper as a doctoral the-
sis to the University of Zurich to receive a Ph.D. By
1909 Einstein had been recognized as a leading scien-
tific thinker. He resigned from the patent office and
was appointed a full professor at the Karl-Ferdinand
University in Prague in 1911. That same year, based on
his theory of relativity, Einstein made a prediction
about how light rays from distant stars would bend
around the Sun, hoping that some day astronomers
might be able to observe this effect and verify that his
theory of relativity is correct. He also began working
on incorporating the role of acceleration (nonuniform
motion) into his special theory to develop a general
theory of relativity. After a number of false starts, Ein-
stein finally published a coherent general theory in
1915. Four years later, during a solar eclipse, British
scientists were able to observe the bending of light rays
just as Einstein had predicted. The popular press cov-
ered the story, and Einstein immediately received world
attention for his achievement.
In 1921 Einstein received the Nobel Prize not for
his relativity theory, but, surprisingly, for his work on
the photoelectric effect. He also received the Copley
158 Einstein, Albert