Conservation of Energy
Year of Discovery: 1847
What Is It? Energy can neither be created nor lost. It may be converted from
one form to another, but the total energy always remains constant within a
closed system.
Who Discovered It? Hermann von Helmholtz
Why Is This One of the 100 Greatest?
Energy is never lost. It can change from one form to another, but the total amount of
energy never changes. That principle has allowed scientists and engineers to create the
power systems that run your lights and house and fuel your car. It’s called conservation of
energy and is one of the most important discoveries in all science. It has been called the
most fundamental concept of all nature. It forms the first law of thermodynamics. It is the
key to understanding energy conversion and the interchangeability of different forms of energy. When Hermann von Hemholtz assembled all of the studies and individual pieces of
information to discover this principle, he changed science and engineering forever.
How Was It Discovered?
Born in 1821 in Potsdam, Germany, Hermann von Hemholtz grew up in a family of
gold merchants. At the age of 16, he took a government scholarship to study medicine in exchange for 10 years of service in the Prussian Army. Officially he studied to be a doctor at
the Berlin Medical Institute. However, he often slipped over to Berlin University to attend
classes on chemistry and physiology.
While serving in the army, he developed a research specialty: proving that the work
muscles did was derived from chemical and physical principles and not from some “unspecified vital force.” Many researchers used “vital forces” as a way to explain anything they
couldn’t really explain. It was as if these “vital forces” could perpetually create energy out
of nothing.
Helmholtz wanted to prove that all muscle-driven motion could be accounted for by
studying physical (mechanical) and chemical reactions within the muscles. He wanted to
discredit the “vital force” theory. During this effort, he developed a deep belief in the concept of conservation of effort and energy. (No work could be created without coming from
somewhere or lost without going somewhere.)
He studied mathematics in order to better describe the conversion of chemical energy
into kinetic energy (motion and work) and the conversion of physical muscle changes into
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