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physics

physics branch of science traditionally defined as the study of matter , energy , and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this name at a few universities. Physics is in some senses the oldest and most basic pure science; its discoveries find applications throughout the natural sciences, since matter and energy are the basic constituents of the natural world. The other sciences are generally more limited in their scope and may be considered branches that have split off from physics to become sciences in their own right. Physics today may be divided loosely into classical physics and modern physics. Classical Physics Classical physics includes the traditional branches and topics that were recognized and fairly well developed before the beginning of the 20th cent.— mechanics , sound , light , heat , and electricity and magnetism . 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, 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 (see spectrum ), 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 cent.; 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. Modern Physics Most of classical physics is concerned with matter and energy on the normal scale of observation; by contrast, 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, being 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. The 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 the quantum theory and the theory of relativity find applications in all areas of modern physics. Evolution of Physics Greek Contributions The earliest history of physics is interrelated with that of the other sciences. A number of contributions were made during the period of Greek civilization, dating from Thales and the early Ionian natural philosophers in the Greek colonies of Asia Minor (6th and 5th cent. BC). Democritus (c.460-370 BC) proposed an atomic theory of matter and extended it to other phenomena as well, but the dominant theories of matter held that it was formed of a few basic elements, usually earth, air, fire, and water. In the school founded by Pythagoras of Samos the principal concept was that of number; it was applied to all aspects of the universe, from planetary orbits to the lengths of strings used to sound musical notes. The most important philosophy of the Greek period was produced by two men at Athens, Plato (427-347 BC) and his student Aristotle (384-322 BC); Aristotle in particular had a critical influence on the development of science in general and physics in particular. The Greek approach to physics was largely geometrical and reached its peak with Archimedes (287-212 BC), who studied a wide range of problems and anticipated the methods of the calculus. Another important scientist of the early Hellenistic period, centered in Alexandria, Egypt, was the astronomer Aristarchus (c.310-220 BC), who proposed a heliocentric, or sun-centered, system of the universe. However, just as the earlier atomic theory had not become generally accepted, so too the astronomical system that eventually prevailed was the geocentric system proposed by Hipparchus (190-120 BC) and developed in detail by Ptolemy (AD 85-AD 165). Preservation of Learning With the passing of the Greek civilization and the Roman civilization that followed it, Greek learning passed into the hands of the Muslim world that spread its influence from the E Mediterranean eastward into Asia, where it picked up contributions from the Chinese (papermaking, gunpowder) and the Hindus (the place-value decimal number system with a zero), and westward as far as Spain, where Islamic culture flourished in Córdoba, Toledo, and other cities. Little specific advance was made in physics during this period, but the preservation and study of Greek science by the Muslim world made possible the revival of learning in the West beginning in the 12th and 13th cent. The Scientific Revolution The first areas of physics to receive close attention were mechanics and the study of planetary motions. Modern mechanics dates from the work of Galileo and Simon Stevin in the late 16th and early 17th cent. The great breakthrough in astronomy was made by Nicolaus Copernicus, who proposed (1543) the heliocentric model of the solar system that was later modified by Johannes Kepler (using observations by Tycho Brahe) into the description of planetary motions that is still accepted today. Galileo gave his support to this new system and applied his discoveries in mechanics to its explanation. The full explanation of both celestial and terrestrial motions was not given until 1687, when Isaac Newton published his Principia [Mathematical Principles of Natural Philosophy]. This work, the most important document of the Scientific Revolution of the 16th and 17th cent., contained Newton's famous three laws of motion and showed how the principle of universal gravitation could be used to explain the behavior not only of falling bodies on the earth but also planets and other celestial bodies in the heavens. To arrive at his results, Newton invented one form of an entirely new branch of mathematics, the calculus (also invented independently by G. W. Leibniz), which was to become an essential tool in much of the later development in most branches of physics. Other branches of physics also received attention during this period. William Gilbert, court physician to Queen Elizabeth I, published (1600) an


From Omilili

Anyone take modern physics?

I have a free elective next semester and I'm thinking about taking modern physics I, but I'm , astrophysics, nuclear physics, solid state physics, etc.) ), and calc basedphysics 1 & 2. While searching for "modern physics" I came across this old post of...

From Yahoo Answers

Question:all physics revolves around gravity, a force wqe really don't know anyything about, only the effets of it, could everything be going in the wrongf direction people seem to agree that gravity came before matter or some other matterless energy, what is this energy why do we only start from scratch with quantum physics, why not with all physics now the insults

Answers:The real problem is that the money for supporting research has chosen to go in only one direction before that direction has really proved itself. Programs that head in directions that might falsify the established theories have no chance to obtain funding. Therefore, we are condemned to live with the mistakes of the past for generations to come. General relativity has done a pretty good job of describing the effects of gravity within a certain range of scales---roughly from 10^-10 meter up to about 10^18 meter. Consequently, scientists have assumed that Newton's universal law of gravitation must hold at all scales and distances. Observations to the contrary are swept under the carpet by inventing fudge factors like dark matter and dark energy. Rather than trying to find the real cause of gravity, they try to pass it off as an intrinsic property of 4D space-time continuum, which is nothing more than a mathematical fantasy.

Question:

Answers:Agriculture - study of producing crops from the land, with an emphasis on practical applications Anatomy - the study of the animal form, with an emphasis on human bodies Biochemistry - the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level Bioengineering - the study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology. Bioinformatics - also classified as a branch of information technology (IT) it is the study, collection, and storage of genomic data Biomathematics or Mathematical Biology - the study of biological processes through mathematics, with an emphasis on modeling. Biomechanics - often considered a branch of medicine, the study of the mechanics of living beings, with an emphasis on applied use through artificial limbs, etc. Biophysics - the study of biological processes through physics, by applying the theories and methods traditionally used in the physical sciences Biotechnology - a new and sometimes controversial branch of biology that studies the manipulation of living matter, including genetic modification Botany - the study of plants Cell Biology - the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell. Conservation Biology - the study of the preservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife Cryobiology - the study of the effects of lower than normally preferred temperatures on living beings. Developmental Biology - the study of the processes through which an organism develops, from zygote to full structure. Ecology - the study of the ecosystem as a complete unit, with an emphasis on how species and groups of species interact with other living beings and non-living elements. Entomology - the study of insects Environmental Biology - the study of the natural world, as a whole or in a particular area, especially as affected by human activity Ethology - the study of animal behavior. Evolution or Evolutionary Biology - the study of the origin and decent of species over time Genetics - the study of genes and heredity. Herpetology - the study of reptiles (and amphibians?) Histology - The study of cells and tissue, a microscopic branch of anatomy. Ichthyology - the study of fish Macrobiology - the study of biology on the level of the macroscopic individual (plant, animal, or other living being) as a complete unit. Mammology - the study of mammals Marine Biology - the study of ocean ecosystems, plants, animals, and other living beings. Medicine - the study of the human body in health and disease, with allopathic medicine focusing on alleviating or curing the body from states of disease Microbiology - the study of microscopic organisms (microorganisms) and their interactions with other living things Molecular Biology - the study of biology and biological functions at the molecular level, some cross over with biochemistry Neurobiology - the study of the nervous system, including anatomy, physiology, even pathology Oceanography - the study of the ocean, including ocean life, environment, geography, weather, and other aspects influencing the ocean. See Marine Biology Ornithology - the study of birds Paleontology - the study of fossils and sometimes geographic evidence of prehistoric life Pathobiology or pathology - the study of diseases, and the causes, processes, nature, and development of disease Parisitology - the study of parasites and parasitism Pharmacology - the study and practical application of preparation, use, and effects of drugs and synthetic medicines. Physiology - the study of the functioning of living organisms and the organs and parts of living organisms Pre-medicine - a college major that covers the general aspects of biology as well as specific classes relevant to the study of medicine Zoology - the study of animals and animal life, including classification, physiology, development, and behavior (See also Entomology, Ethology, Herpetology, Ichthyology, Mammology, Ornithology

Question:

Answers:Aerodynamics: the study of the motion of gas on objects and the forces created Anatomy: the study of the structure and organization of living things Anthropology: the study of human cultures both past and present Archaeology: the study of the material remains of cultures Astronomy: the study of celestial objects in the universe Astrophysics: the study of the physics of the universe Bacteriology: the study of bacteria in relation to disease Biochemistry: the study of the organic chemistry of compounds and processes occurring in organisms Biophysics: the application of theories and methods of the physical sciences to questions of biology Biology: the science that studies living organisms Botany: the scientific study of plant life Chemical Engineering: the application of science, mathematics, and economics to the process of converting raw materials or chemicals into more useful or valuable forms Chemistry: the science of matter and its interactions with energy and itself Climatology: the study of climates and investigations of its phenomena and causes Computer Science: the systematic study of computing systems and computation Ecology: the study of how organisms interact with each other and their environment Electronics: science and technology of electronic phenomena Engineering: the practical application of science to commerce or industry Entomology: the study of insects Environmental Science: the science of the interactions between the physical, chemical, and biological components of the environment Forestry: the science of studying and managing forests and plantations, and related natural resources Genetics: the science of genes, heredity, and the variation of organisms Geology: the science of the Earth, its structure, and history Mathematics: a science dealing with the logic of quantity and shape and arrangement Medicine: the science concerned with maintaining health and restoring it by treating disease Hope This Helps :)


From Youtube

Lecture 2 | Modern Physics: Statistical Mechanics

April 6, 2009 - Leonard Susskind overviews elementary mathematics to define a method for understanding statistical mechanics. Stanford University: www.stanford.edu Stanford Continuing Studies Program: csp.stanford.edu Stanford University Channel on YouTube: www.youtube.com

Lecture 3 | Modern Physics: Statistical Mechanics

April 13, 2009 - Leonard Susskind reviews the Lagrange multiplier, explains Boltzmann distribution and Helm-Holtz free energy before oulining into the theory of fluctuations. Stanford University: www.stanford.edu Stanford Continuing Studies Program: csp.stanford.edu Stanford University Channel on YouTube: www.youtube.com

Lecture 1 | Modern Physics: Statistical Mechanics

March 30, 2009 - Leonard Susskind discusses the study of statistical analysis as calculating the probability of things subject to the constraints of a conserved quantity. Susskind introduces energy, entropy, temperature, and phase states as they relate directly to statistical mechanics. Stanford University: www.stanford.edu Stanford Continuing Studies Program: csp.stanford.edu Stanford University Channel on YouTube: www.youtube.com

Lecture 8 | Modern Physics: Statistical Mechanics

May 19, 2009 - Leonard Susskind lectures on a new class of systems, magnetic systems. He goes on to talk about mean field approximations of molecules in multidimensional lattice systems. Stanford University: www.stanford.edu Stanford Continuing Studies Program: csp.stanford.edu Stanford University Channel on YouTube: www.youtube.com


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