202
OUANTA ARE
DISCRETE
PACKETS
OF ENERGY
MAX PLANCK (1858–1947)
I
n December 1900, the German
theoretical physicist Max
Planck presented a paper
setting out his method for resolving
a long-standing theoretical conflict.
In doing so, he made one of the
most important conceptual leaps
in the history of physics. Planck’s
paper marked the turning point
between the classical mechanics of
Newton and quantum mechanics.
The certainty and precision of
Newtonian mechanics was to give
way to an uncertain, probabilistic
description of the universe.
Quantum theory has its roots in
the study of thermal radiation, the
phenomenon that explains why we
feel heat from a fire, even when theIN CONTEXT
BRANCH
PhysicsBEFORE
1860 The distribution of
so-called black-body radiation
fails to match predictions
made by theoretical models.1870s Austrian physicist
Ludwig Boltzmann’s analysis
of entropy (disorder) introduces
a probabilistic interpretation of
quantum mechanics.AFTER
1905 Albert Einstein proposes
that the quantum is a real
entity, using Planck’s concept
of quantized light to introduce
the idea of the photon.1924 Louis de Broglie proves
that matter behaves both as a
particle and as a wave.1926 Erwin Schrödinger
formulates an equation for the
wave behavior of particles.