Physics (from Ancient Greek: phusikḗ) which stands for “knowledge of nature”, is the
natural science that involves the study of matter and its motion through space
and time, along with related concepts such as energy and force. More broadly,
it is the general analysis of nature, conducted in order to understand how the
universe behaves.
Physics is one of the oldest academic disciplines, perhaps
the oldest through its inclusion of astronomy. Physics intersects with many
interdisciplinary areas of research, such as biophysics and quantum chemistry,
and the boundaries of physics are not rigidly defined. New ideas in physics
often explain the fundamental mechanisms of other sciences while opening new
avenues of research in areas such as mathematics and philosophy.
Physics also makes significant contributions through
advances in new technologies that arise from theoretical breakthroughs. For
example:
- advances in the understanding of electromagnetism or
nuclear physics led directly to the development of new products which have
dramatically transformed modern-day society, such as television,
computers,domestic appliances, and nuclear weapons
- advances in thermodynamics led to the development of
industrialization and
- advances in mechanics inspired the development of
calculus.
The History of Physics can be explained as follows:
Astronomy:
Astronomy is the oldest of the natural sciences. The
earliest civilizations dating back to beyond 3000 BCE, such as the Sumerians,
Ancient Egyptians, and the Indus Valley Civilization, all had a predictive
knowledge and a basic understanding of the motions of the Sun, Moon, and stars.
The stars and planets were often a target of worship, believed to represent
their gods. While the explanations for these phenomena were often unscientific
and lacking in evidence, these early observations laid the foundation for later
astronomy.
Philosophy:
Natural philosophy has its origins in Greece during the
Archaic period, (650 BCE – 480 BCE), when Pre-Socratic philosophers like Thales
rejected non-naturalistic explanations for natural phenomena and proclaimed
that every event had a natural cause.They proposed ideas verified by reason and
observation, and many of their hypotheses proved successful in experiment.
Classical physics:
Sir Isaac Newton (1643–1727), whose laws of motion and
universal gravitation were major milestones in classical physics. Physics became a separate science when early modern
Europeans used experimental and quantitative methods to discover what are now
considered to be the laws of physics.
Major developments in this period include the replacement of
the geocentric model of the solar system with the Sun-centric Copernican model,
the laws governing the motion of planetary bodies determined by Johannes Kepler
between 1609 and 1619, pioneering work on telescopes and observational
astronomy by Galileo Galilei in the 16th and 17th Centuries, and Isaac Newton's
discovery and unification of the laws of motion and universal gravitation that
would come to bear his name.Newton also developed calculus, the mathematical
study of change, which provided new mathematical methods for solving physical
problems.
The discovery of new laws in thermodynamics, chemistry, and
electromagnetics resulted from greater research efforts during the Industrial
Revolution as energy needs increased. The laws comprising classical physics
remain very widely used for objects on everyday scales travelling at
non-relativistic speeds, since they provide a very close approximation in such
situations, and theories such as quantum mechanics and the theory of relativity
simplify to their classical equivalents at such scales. However, inaccuracies
in classical mechanics for very small objects and very high velocities led to
the development of modern physics in the 20th century.
Modern physics:
Albert Einstein (1879–1955), whose work on the photoelectric
effect and the theory of relativity led to a revolution in 20th century
physics.
Modern physics began in the early 20th century with the work
of Max Planck in quantum theory and Albert Einstein's theory of relativity.
Both of these theories came about due to inaccuracies in classical mechanics in
certain situations. Classical mechanics predicted a varying speed of light,
which could not be resolved with the constant speed predicted by Maxwell's
equations of electromagnetism; this discrepancy was corrected by Einstein's
theory of special relativity, which replaced classical mechanics for fast-moving
bodies and allowed for a constant speed of light.
Black body radiation provided another problem for classical
physics, which was corrected when Planck proposed that light comes in
individual packets known as photons; this, along with the photoelectric effect
and a complete theory predicting discrete energy levels of electron orbitals,
led to the theory of quantum mechanics taking over from classical physics at
very small scales.
Quantum mechanics would come to be pioneered by Werner
Heisenberg, Erwin Schrödinger and Paul Dirac.From this early work, and work in
related fields, the Standard Model of particle physics was derived. Following
the discovery of a particle with properties consistent with the Higgs boson at
CERN in 2012, all fundamental particles predicted by the standard model, and no
others, appear to exist; however physics beyond the Standard Model, with
theories such as supersymmetry, is an active area of research.
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