This article deals with the history of classical mechanics.
2 Medieval thought
3 Modern age – formation of classical mechanics
5 See also
Main article: Aristotelian physics
Aristotle's laws of motion. In
Physics he states that objects fall at
a speed proportional to their weight and inversely proportional to the
density of the fluid they are immersed in. This is a correct
approximation for objects in Earth's gravitational field moving in air
The ancient Greek philosophers,
Aristotle in particular, were among
the first to propose that abstract principles govern nature. Aristotle
argued, in On the Heavens, that terrestrial bodies rise or fall to
their "natural place" and stated as a law the correct approximation
that an object's speed of fall is proportional to its weight and
inversely proportional to the density of the fluid it is falling
Aristotle believed in logic and observation but it would be more than
eighteen hundred years before
Francis Bacon would first develop the
scientific method of experimentation, which he called a vexation of
Aristotle saw a distinction between "natural motion" and "forced
motion", and he believed that in a hypothetical vacuum, there would be
no reason for a body to move naturally toward one point rather than
any other, and so he concluded a body in a vacuum must either stay at
rest or else move indefinitely fast. In this way,
Aristotle was the
first to approach something similar to the law of inertia. However, he
believed a vacuum would be impossible because the surrounding air
would rush in to fill it immediately. He also believed that an object
would stop moving in an unnatural direction once the applied forces
were removed. Later Aristotelians developed an elaborate explanation
for why an arrow continues to fly through the air after it has left
the bow, proposing that an arrow creates a vacuum in its wake, into
which air rushes, pushing it from behind. Aristotle's beliefs were
influenced by Plato's teachings on the perfection of the circular
uniform motions of the heavens. As a result, he conceived of a natural
order in which the motions of the heavens were necessarily perfect, in
contrast to the terrestrial world of changing elements, where
individuals come to be and pass away.
Galileo would later observe "the resistance of the air exhibits itself
in two ways: first by offering greater impedance to less dense than to
very dense bodies, and secondly by offering greater resistance to a
body in rapid motion than to the same body in slow motion".
Jean Buridan developed the Theory of impetus. Albert,
Bishop of Halberstadt, developed the theory further.
Modern age – formation of classical mechanics
It wasn't until
Galileo Galilei's development of the telescope and his
observations that it became clear that the heavens were not made from
a perfect, unchanging substance. Adopting Copernicus's heliocentric
Galileo believed the
Earth was the same as other planets.
Galileo may have performed the famous experiment of dropping two
cannonballs from the tower of Pisa. (The theory and the practice
showed that they both hit the ground at the same time.) Though the
reality of this experiment is disputed, he did carry out quantitative
experiments by rolling balls on an inclined plane; his correct theory
of accelerated motion was apparently derived from the results of the
Galileo also found that a body dropped vertically hits
the ground at the same time as a body projected horizontally, so an
Earth rotating uniformly will still have objects falling to the ground
under gravity. More significantly, it asserted that uniform motion is
indistinguishable from rest, and so forms the basics of the theory of
Isaac Newton was the first to unify the three laws of motion (the
law of inertia, his second law mentioned above, and the law of action
and reaction), and to prove that these laws govern both earthly and
celestial objects. Newton and most of his contemporaries, with the
notable exception of Christiaan Huygens, hoped that classical
mechanics would be able to explain all entities, including (in the
form of geometric optics) light. Newton's own explanation of Newton's
rings avoided wave principles and supposed that the light particles
were altered or excited by the glass and resonated.
Newton also developed the calculus which is necessary to perform the
mathematical calculations involved in classical mechanics. However it
Gottfried Leibniz who, independently of Newton, developed a
calculus with the notation of the derivative and integral which are
used to this day.
Classical mechanics retains Newton's dot notation
for time derivatives.
Leonhard Euler extended
Newton's laws of motion
Newton's laws of motion from particles to
rigid bodies with two additional laws.
After Newton, re-formulations progressively allowed solutions to a far
greater number of problems. The first was constructed in 1788 by
Joseph Louis Lagrange, an Italian-French mathematician. In Lagrangian
mechanics the solution uses the path of least action and follows the
calculus of variations.
William Rowan Hamilton
William Rowan Hamilton re-formulated
Lagrangian mechanics in 1833. The advantage of Hamiltonian mechanics
was that its framework allowed a more in-depth look at the underlying
principles. Most of the framework of
Hamiltonian mechanics can be seen
in quantum mechanics however the exact meanings of the terms differ
due to quantum effects.
Although classical mechanics is largely compatible with other
"classical physics" theories such as classical electrodynamics and
thermodynamics, some difficulties were discovered in the late 19th
century that could only be resolved by more modern physics. When
combined with classical thermodynamics, classical mechanics leads to
Gibbs paradox in which entropy is not a well-defined quantity. As
experiments reached the atomic level, classical mechanics failed to
explain, even approximately, such basic things as the energy levels
and sizes of atoms. The effort at resolving these problems led to the
development of quantum mechanics. Similarly, the different behaviour
of classical electromagnetism and classical mechanics under velocity
transformations led to the theory of relativity.
By the end of the 20th century, classical mechanics in physics was no
longer an independent theory. Along with classical electromagnetism,
it has become imbedded in relativistic quantum mechanics or quantum
field theory. It defines the non-relativistic, non-quantum
mechanical limit for massive particles.
Classical mechanics has also been a source of inspiration for
mathematicians. The realization that the phase space in classical
mechanics admits a natural description as a symplectic manifold
(indeed a cotangent bundle in most cases of physical interest), and
symplectic topology, which can be thought of as the study of global
issues of Hamiltonian mechanics, has been a fertile area of
mathematics research since the 1980s.
Timeline of classical mechanics
^ a b Rovelli, Carlo (2015). "Aristotle's Physics: A Physicist's
Look". Journal of the American Philosophical Association. 1 (1):
^ Peter Pesic (March 1999). "Wrestling with Proteus:
Francis Bacon and
the "Torture" of Nature". Isis. The University of Chicago Press on
behalf of The History of Science Society. 90 (1): 81–94.
doi:10.1086/384242. JSTOR 237475.
Galileo Galilei, Dialogues Concerning Two New Sciences by Galileo
Galilei. Translated from the Italian and Latin into English by Henry
Crew and Alfonso de Salvio. With an Introduction by Antonio Favaro
(New York: Macmillan, 1914). Chapter: The Motion of Projectiles
Truesdell, C. (1968). Essays in the History of Mechanics. Berlin,
Heidelberg: Springer Berlin Heidelberg. ISBN 9783642866470.
Maddox, René Dugas ; foreword by Louis de Broglie ;
translated into English by J.R. (1988). A history of mechanics (Dover
ed.). New York: Dover Publications. ISBN 0-486-65632-2.
Buchwald, Jed Z.; Fox, Robert, eds. (2013). The Oxford handbook of the
history of physics (First ed.). Oxford: Oxford University Press.
pp. 358–405. ISBN 97