- 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