Physics is that branch of science that deals with matter , energy and interrelation or interaction between them...
This energy can take the form of motion, light, electricity,
radiation, gravity . . . just about anything, honestly. Physics deals with
matter on scales ranging from sub-atomic particles (i.e. the particles that
make up the atom and the particles that make up those particles) to stars and
even entire galaxies.
How Physics Works
As an experimental science, physics utilizes the scientific
method to formulate and test hypotheses that are based on observation of the
natural world. The goal of physics is to use the results of these experiments
to formulate scientific laws,...
usually expressed in the language of mathematics, which can then be used to predict other phenomena.
usually expressed in the language of mathematics, which can then be used to predict other phenomena.
History
To understand the behavior of natural phenomena and their effects evolved from philosophy, progressively replaced by natural philosophy then natural science, to eventually arrive at the modern conception of physics.
Natural philosophy has its origins in Greece during the Archaic period, (650 BCE – 480 BCE), when Pre-Socratic philosophers like Thales refused supernatural, religious or mythological explanations for natural phenomena and proclaimed that every event had a natural cause.[8] They proposed ideas verified by reason and observation and many of their hypotheses proved successful in experiment, for example atomism.
Classical physics became a separate science when early modern Europeans used these experimental and quantitative methods to discover what are now considered to be the laws of physics. Kepler, Galileo and more specifically Newton discovered and unified the different laws of motion. Experimental physics had its debuts with experimentation concerning statics by medieval Muslim physicists like al-Biruni and Alhazen. During the industrial revolution, as energy needs increased, so did research, which led to the discovery of new laws in thermodynamics, chemistry and electromagnetics.
Modern physics started with the works of Max Planck in quantum theory and Einstein in relativity, and continued in quantum mechanics pioneered by Heisenberg, Schrödinger and Paul Dirac.
The Role of Physics in Science
In a broader sense, physics can be seen as the most
fundamental of the natural sciences. Chemistry, for example, can be viewed as a
complex application of physics, as it focuses on the interaction of energy and
matter in chemical systems. We also know that biology is, at its heart, an
application of chemical properties in living things, which means that it is
also, ultimately, ruled by the physical laws.
Major Concepts in Physics
Because physics covers so much area, it is divided into
several specific fields of study, such as electronics, quantum physics,
astronomy, and biophysics.
Classical Physics
Classical Physics
Classical physics includes the traditional branches and
topics that were recognized and well-developed before the beginning of the 20th
century—classical mechanics, acoustics, optics, thermodynamics, and
electromagnetism. Classical mechanics is concerned with bodies acted on by
forces and bodies in motion and may be divided into statics (study of the
forces on a body or bodies at rest), kinematics (study of motion without regard
to its causes), and dynamics (study of motion and the forces that affect it);
mechanics may also be divided into solid mechanics and fluid mechanics (known
together as continuum mechanics), the latter including such branches as
hydrostatics, hydrodynamics, aerodynamics, and pneumatics. Acoustics, the study
of sound, is often considered a branch of mechanics because sound is due to the
motions of the particles of air or other medium through which sound waves can
travel and thus can be explained in terms of the laws of mechanics. Among the
important modern branches of acoustics is ultrasonics, the study of sound waves
of very high frequency beyond the range of human hearing. Optics, the study of
light, is concerned not only with visible light but also with infrared and
ultraviolet radiation, which exhibit all of the phenomena of visible light
except visibility, e.g., reflection, refraction, interference, diffraction,
dispersion, and polarization of light. Heat is a form of energy, the internal
energy possessed by the particles of which a substance is composed;
thermodynamics deals with the relationships between heat and other forms of
energy. Electricity and magnetism have been studied as a single branch of
physics since the intimate connection between them was discovered in the early
19th century; an electric current gives rise to a magnetic field and a changing
magnetic field induces an electric current. Electrostatics deals with electric
charges at rest, electrodynamics with moving charges, and magnetostatics with
magnetic poles at rest.
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Modern Physics
Classical physics is generally concerned with matter and
energy on the normal scale of observation, while much of modern physics is
concerned with the behavior of matter and energy under extreme conditions or on
the very large or very small scale. For example, atomic and nuclear physics
studies matter on the smallest scale at which chemical elements can be
identified. The physics of elementary particles is on an even smaller scale, as
it is concerned with the most basic units of matter; this branch of physics is
also known as high-energy physics because of the extremely high energies
necessary to produce many types of particles in large particle accelerators. On
this scale, ordinary, commonsense notions of space, time, matter, and energy
are no longer valid.
The two chief theories of modern physics present a different
picture of the concepts of space, time, and matter from that presented by
classical physics. Quantum theory is concerned with the discrete, rather than
continuous, nature of many phenomena at the atomic and subatomic level, and
with the complementary aspects of particles and waves in the description of
such phenomena. The theory of relativity is concerned with the description of phenomena
that take place in a frame of reference that is in motion with respect to an
observer; the special theory of relativity is concerned with relative uniform
motion in a straight line and the general theory of relativity with accelerated
motion and its connection with gravitation. Both quantum theory and the theory
of relativity find applications in all areas of modern physics.
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Difference between Classical and Modern Physics
While physics aims to discover universal laws, its theories
lie in explicit domains of applicability. Loosely speaking, the laws of
classical physics accurately describe systems whose important length scales are
greater than the atomic scale and whose motions are much slower than the speed
of light. Outside of this domain, observations do not match their predictions.
Albert Einstein contributed the framework of special relativity, which replaced
notions of absolute time and space with spacetime and allowed an accurate
description of systems whose components have speeds approaching the speed of
light. Max Planck, Erwin Schrödinger, and others introduced quantum mechanics,
a probabilistic notion of particles and interactions that allowed an accurate
description of atomic and subatomic scales. Later, quantum field theory unified
quantum mechanics and special relativity. General relativity allowed for a
dynamical, curved spacetime, with which highly massive systems and the
large-scale structure of the universe can be well-described. General relativity
has not yet been unified with the other fundamental descriptions; several
candidate theories of quantum gravity are being developed.
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