Anti-Semitism - · The hatred of Jews. Anti-Semitism was common in Germany even
before the 1930s, but it increased as economic conditions grew
worse and as the German people grew more discontented and looked
for someone to blame. Adolf Hitler capitalized on this rising wave
of anti-Semitism, riding it to power. Once Hitler was in power,
anti-Semitism became a government policy, and Jews across the country
were driven by their jobs and persecuted by their neighbors.
Appeal of the Ninety-Three Intellectuals - · A manifesto signed by ninety-three German intellectuals
in support of German military action in World War I. Many of these
academics were so eager to announce their support of the fatherland
that they signed without reading it. It was a move they came to
regret. After the war, the German intellectual community was shunned
by many of their European colleagues, in part due to their signatures
on this type of document.
Blackbody Radiation - · A blackbody is a black box that absorbs all the radiation
directed at it. The amount of energy it emits is independent of
the size or shape of the box and depends only on temperature. The
concept was introduced by Robert Kirchhoff in 1859. For decades afterward,
physicists struggled with trying to figure out the spectrum of
the energy emitted by the blackbody. But the problem remained unsolved
until 1900, when Planck finally came up with a working formula.
Copenhagen Interpretation - · The interpretation of quantum physics that came to
be accepted in the late 1920s. Planck disliked the theory, believing
that it was a way of giving up on the important questions. If the Copenhagen
Interpretation was correct, Planck reasoned, it would mean that
scientists could never learn any objective facts about the universe.
E = hv - · In this equation that made Planck famous, E stands
for energy, v stands for frequency, and h is
a constant, now known as Planck's constant. The equation defines
the relationship between energy and frequency in a blackbody. The
radical implication of this equation was that light came in finite
packets, multiples of hv.
International Research Council - · A scientific organization founded in 1919, which was
designed to shut German scientists out of the international scientific community.
Planck and his colleagues battled to get German scientists admitted
to the organization's meetings, projects, and publications. They
Positivism - · A philosophy of science asserting that scientific
truths can only come from and refer to scientists' direct experience
with the world. According to the positivists, there is no objective
reality, no deeper truth. Fact can only come from direct, subjective observation.
Physics - · The new system of physics created at the beginning
of the twentieth century to explain the bizarre, counterintuitive behavior
of light and subatomic particles. Physicists realized that activity
on this small scale could not be described using physical models
from the larger world, and they were forced to cobble together
a new understanding of the way the basic particles of matter interact.
The creation of quantum physics constituted an exciting revolution
in the way people studied and applied physics.
Solvay Conference - · A series of conferences about the problems of quantum
physics that attracted top physicists from all over Europe. Planck
was invited to the 1927 conference, even though his most productive years
were behind him. The invitation was symbolic of his position as
the father of quantum physics and of a new spirit of tolerance
and acceptance toward the German scientists.
University of Göttingen - · The German center of the quantum physics revolution.
- Bohr's theory of complementarity was one of two components
of the Copenhagen interpretation of quantum physics. It proposed
that science will never be able to answer the question of whether
light "is" a particle or a wave. Science is about the results of experiments,
not about the way things really are, and the design of the experiment
dictated whether the light would be measured as a particle or a
- The most famous scientist of the twentieth century. In
1905, Einstein introduced the theory of relativity, which overturned
the classic Newtonian physics that had dominated the field for
hundreds of years. This was the same year he published his paper
on blackbody radiation, which reinterpreted Planck's famous equation
as evidence that light was emitted in quanta, rather than waves.
Einstein, a Jew, left Germany when the Nazis came to power and
moved to the United States, where he lived out the rest of his
life. For more information, see SparkNote on Albert Einstein
- Heisenberg's Uncertainty Principle was one of two
components of the Copenhagen interpretation of quantum physics.
It asserted that it was impossible for an observer to know both
the exact position and the exact momentum of a subatomic particle.
Heisenberg, like Planck, also stayed in Germany throughout World War
II. After the war, some doubt remained as to whether Heisenberg
had actively helped the Nazis develop an atomic bomb.
- The leader of Germany's national socialist workers' (Nazi)
party. In 1933, Hitler was elected the Chancellor of the German
Reich. He carried out a ruthless campaign against the German Jews, culminating
in the Holocaust. His hunger for power and territorial conquest
led the country into World
Marga Von Hoesslin
- Planck's second wife. Planck married Marga Von Hoesslin
a year after his first wife died. Planck and Marga were married
for twenty-three years, and they raised four children together.
- The author of Deutsche Physik,
work that proclaimed the superiority of German science. By German
science, Lenard meant Aryan science–he claimed that relativity
and quantum physics were perverse, non-Aryan creations, part of
an international Jewish conspiracy led by men such as Einstein.
- Planck's longest surviving son. Planck's other three children
all died within a year after World War I. In 1945, Erwin Planck
was executed for conspiring to assassinate Hitler.
- A German physicist working on the blackbody radiation
problem at the end of the nineteenth century. Wien developed a
formula for the energy distribution that seemed to work but was
eventually proven incorrect. Planck and Wien remained lifelong