Physics
This article is about the field of science. For other uses, see Physics (disambiguation).Not to be confused with Physical science.Various examples of physical phenomena

Physics (from Ancient Greek: φυσική (ἐπιστήμη), translit. physikḗ (epistḗmē),lit. 'knowledge of nature', from φύσις phýsis "nature")[1][2][3] is the natural science that studies matter[4] and its motion and behavior through space and time and that studies the related entities of energy and force.[5] Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.[a][6][7][8] (from Ancient Greek: φυσική (ἐπιστήμη), translit. physikḗ (epistḗmē),lit. 'knowledge of nature', from φύσις phýsis "nature")[1][2][3] is the natural science that studies matter[4] and its motion and behavior through space and time and that studies the related entities of energy and force.[5] Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.[a][6][7][8] (from Ancient Greek: φυσική (ἐπιστήμη), translit. physikḗ (epistḗmē),lit. 'knowledge of nature', from φύσις phýsis "nature")[1][2][3] is the natural science that studies matter[4] and its motion and behavior through space and time and that studies the related entities of energy and force.[5] Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.[a][6][7][8]

Physics is one of the oldest academic disciplines and, through its inclusion ofastronomy, perhaps the oldest.[9] Over the last two millennia, physics,chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the scientific revolution in the 17th century, these natural sciences emerged as unique research endeavors in their own right.[b] Physics intersects with many interdisciplinary areas of research, such as biophysicsand quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences[6] and suggest new avenues of research in academic disciplines such as mathematics and philosophy.academic disciplines and, through its inclusion ofastronomy, perhaps the oldest.[9] Over the last two millennia, physics,chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the scientific revolution in the 17th century, these natural sciences emerged as unique research endeavors in their own right.[b] Physics intersects with many interdisciplinary areas of research, such as biophysicsand quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences[6] and suggest new avenues of research in academic disciplines such as mathematics and philosophy.academic disciplines and, through its inclusion ofastronomy, perhaps the oldest.[9] Over the last two millennia, physics,chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the scientific revolution in the 17th century, these natural sciences emerged as unique research endeavors in their own right.[b] Physics intersects with many interdisciplinary areas of research, such as biophysicsand quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences[6] and suggest new avenues of research in academic disciplines such as mathematics and philosophy.

Advances in physics often enable advances in new technologies. For example, advances in the understanding of electromagnetism and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons;[6] advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.technologies. For example, advances in the understanding of electromagnetism and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons;[6] advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.technologies. For example, advances in the understanding of electromagnetism and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons;[6] advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.

History
Main article: History of physicsAncient astronomy
Main article: History of astronomyAncient Egyptian astronomy is evident in monuments like the ceiling of Senemut's tomb from theEighteenth Dynasty of Egypt.

Astronomy is one of the oldest natural sciences. Early civilizations dating back to beyond 3000 BCE, such as the Sumerians, ancient Egyptians, and the Indus Valley Civilization, had a predictive knowledge and a basic understanding of the motions of the Sun, Moon, and stars. The stars and planets were often worshipped, believed to represent gods. While the explanations for the observed positions of the stars were often unscientific and lacking in evidence, these early observations laid the foundation for later astronomy, as the stars were found to traverse great circles across the sky,[9] which however did not explain the positions of the planets. is one of the oldest natural sciences. Early civilizations dating back to beyond 3000 BCE, such as the Sumerians, ancient Egyptians, and the Indus Valley Civilization, had a predictive knowledge and a basic understanding of the motions of the Sun, Moon, and stars. The stars and planets were often worshipped, believed to represent gods. While the explanations for the observed positions of the stars were often unscientific and lacking in evidence, these early observations laid the foundation for later astronomy, as the stars were found to traverse great circles across the sky,[9] which however did not explain the positions of the planets. is one of the oldest natural sciences. Early civilizations dating back to beyond 3000 BCE, such as the Sumerians, ancient Egyptians, and the Indus Valley Civilization, had a predictive knowledge and a basic understanding of the motions of the Sun, Moon, and stars. The stars and planets were often worshipped, believed to represent gods. While the explanations for the observed positions of the stars were often unscientific and lacking in evidence, these early observations laid the foundation for later astronomy, as the stars were found to traverse great circles across the sky,[9] which however did not explain the positions of the planets.

According to Asger Aaboe, the origins of Western astronomy can be found inMesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy.[11] Egyptian astronomers left monuments showing knowledge of the constellations and the motions of the celestial bodies,[12] while Greek poet Homer wrote of various celestial objects in his Iliadand Odyssey; later Greek astronomers provided names, which are still used today, for most constellations visible from the northern hemisphere.[13]Asger Aaboe, the origins of Western astronomy can be found inMesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy.[11] Egyptian astronomers left monuments showing knowledge of the constellations and the motions of the celestial bodies,[12] while Greek poet Homer wrote of various celestial objects in his Iliadand Odyssey; later Greek astronomers provided names, which are still used today, for most constellations visible from the northern hemisphere.[13]Asger Aaboe, the origins of Western astronomy can be found inMesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy.[11] Egyptian astronomers left monuments showing knowledge of the constellations and the motions of the celestial bodies,[12] while Greek poet Homer wrote of various celestial objects in his Iliadand Odyssey; later Greek astronomers provided names, which are still used today, for most constellations visible from the northern hemisphere.[13]

Natural philosophy
Main article: Natural 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.[14] They proposed ideas verified by reason and observation, and many of their hypotheses proved successful in experiment;[15]for example, atomism was found to be correct approximately 2000 years after it was proposed by Leucippus and his pupil Democritus.[16] 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.[14] They proposed ideas verified by reason and observation, and many of their hypotheses proved successful in experiment;[15]for example, atomism was found to be correct approximately 2000 years after it was proposed by Leucippus and his pupil Democritus.[16] 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.[14] They proposed ideas verified by reason and observation, and many of their hypotheses proved successful in experiment;[15]for example, atomism was found to be correct approximately 2000 years after it was proposed by Leucippus and his pupil Democritus.[16]

Physics in the medieval European and Islamic world
Main article: European science in the Middle AgesMain article: Physics in the medieval Islamic worldThe basic way a pinhole camera works

The Western Roman Empire fell in the fifth century, and this resulted in a decline in intellectual pursuits in the western part of Europe. By contrast, theEastern Roman Empire (also known as the Byzantine Empire) resisted the attacks from the barbarians, and continued to advance various fields of learning, including physics.[17]Western Roman Empire fell in the fifth century, and this resulted in a decline in intellectual pursuits in the western part of Europe. By contrast, theEastern Roman Empire (also known as the Byzantine Empire) resisted the attacks from the barbarians, and continued to advance various fields of learning, including physics.[17]Western Roman Empire fell in the fifth century, and this resulted in a decline in intellectual pursuits in the western part of Europe. By contrast, theEastern Roman Empire (also known as the Byzantine Empire) resisted the attacks from the barbarians, and continued to advance various fields of learning, including physics.[17]

In the sixth century Isidore of Miletus created an important compilation of Archimedes' works that are copied in the Archimedes Palimpsest.Archimedes Palimpsest.Archimedes Palimpsest.

In sixth century Europe John Philoponus, a Byzantine scholar, questioned Aristotle's teaching of physics and noting its flaws. He introduced the theory of impetus. Aristotle's physics was not scrutinized until John Philoponus appeared, and unlike Aristotle who based his physics on verbal argument, Philoponus relied on observation. On Aristotle's physics John Philoponus wrote:John Philoponus, a Byzantine scholar, questioned Aristotle's teaching of physics and noting its flaws. He introduced the theory of impetus. Aristotle's physics was not scrutinized until John Philoponus appeared, and unlike Aristotle who based his physics on verbal argument, Philoponus relied on observation. On Aristotle's physics John Philoponus wrote:John Philoponus, a Byzantine scholar, questioned Aristotle's teaching of physics and noting its flaws. He introduced the theory of impetus. Aristotle's physics was not scrutinized until John Philoponus appeared, and unlike Aristotle who based his physics on verbal argument, Philoponus relied on observation. On Aristotle's physics John Philoponus wrote:

“But this is completely erroneous, and our view may be corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as the other, you will see that the ratio of the times required for the motion does not depend on the ratio of the weights, but that the difference in time is a very small one. And so, if the difference in the weights is not considerable, that is, of one is, let us say, double the other, there will be no difference, or else an imperceptible difference, in time, though the difference in weight is by no means negligible, with one body weighing twice as much as the other”[18]But this is completely erroneous, and our view may be corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as the other, you will see that the ratio of the times required for the motion does not depend on the ratio of the weights, but that the difference in time is a very small one. And so, if the difference in the weights is not considerable, that is, of one is, let us say, double the other, there will be no difference, or else an imperceptible difference, in time, though the difference in weight is by no means negligible, with one body weighing twice as much as the other”[18]But this is completely erroneous, and our view may be corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as the other, you will see that the ratio of the times required for the motion does not depend on the ratio of the weights, but that the difference in time is a very small one. And so, if the difference in the weights is not considerable, that is, of one is, let us say, double the other, there will be no difference, or else an imperceptible difference, in time, though the difference in weight is by no means negligible, with one body weighing twice as much as the other”[18]

John Philoponus' criticism of Aristotelian principles of physics served as an inspiration for Galileo Galilei ten centuries later, during the Scientific Revolution. Galileo cited Philoponus substantially in his works when arguing that Aristotelian physics was flawed.[19][20] In the 1300s Jean Buridan, a teacher in the faculty of arts at the University of Paris, developed the concept of impetus. It was a step toward the modern ideas of inertia and momentum.[21]Galileo Galilei ten centuries later, during the Scientific Revolution. Galileo cited Philoponus substantially in his works when arguing that Aristotelian physics was flawed.[19][20] In the 1300s Jean Buridan, a teacher in the faculty of arts at the University of Paris, developed the concept of impetus. It was a step toward the modern ideas of inertia and momentum.[21]Galileo Galilei ten centuries later, during the Scientific Revolution. Galileo cited Philoponus substantially in his works when arguing that Aristotelian physics was flawed.[19][20] In the 1300s Jean Buridan, a teacher in the faculty of arts at the University of Paris, developed the concept of impetus. It was a step toward the modern ideas of inertia and momentum.[21]

Islamic scholarship inherited Aristotelian physics from the Greeks and during the Islamic Golden Age developed it further, especially placing emphasis on observation and a priori reasoning, developing early forms of the scientific method. inherited Aristotelian physics from the Greeks and during the Islamic Golden Age developed it further, especially placing emphasis on observation and a priori reasoning, developing early forms of the scientific method. inherited Aristotelian physics from the Greeks and during the Islamic Golden Age developed it further, especially placing emphasis on observation and a priori reasoning, developing early forms of the scientific method.

The most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics (also known as Kitāb al-Manāẓir), written by Ibn al-Haytham, in which he conclusively disproved the ancient Greek idea about vision, but also came up with a new theory. In the book, he presented a study of the phenomenon of the camera obscura (his thousand-year-old version of the pinhole camera) and delved further into the way the eye itself works. Using dissections and the knowledge of previous scholars, he was able to begin to explain how light enters the eye. He asserted that the light ray is focused, but the actual explanation of how light projected to the back of the eye had to wait until 1604. His Treatise on Lightexplained the camera obscura, hundreds of years before the modern development of photography.[22]Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics (also known as Kitāb al-Manāẓir), written by Ibn al-Haytham, in which he conclusively disproved the ancient Greek idea about vision, but also came up with a new theory. In the book, he presented a study of the phenomenon of the camera obscura (his thousand-year-old version of the pinhole camera) and delved further into the way the eye itself works. Using dissections and the knowledge of previous scholars, he was able to begin to explain how light enters the eye. He asserted that the light ray is focused, but the actual explanation of how light projected to the back of the eye had to wait until 1604. His Treatise on Lightexplained the camera obscura, hundreds of years before the modern development of photography.[22]Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics (also known as Kitāb al-Manāẓir), written by Ibn al-Haytham, in which he conclusively disproved the ancient Greek idea about vision, but also came up with a new theory. In the book, he presented a study of the phenomenon of the camera obscura (his thousand-year-old version of the pinhole camera) and delved further into the way the eye itself works. Using dissections and the knowledge of previous scholars, he was able to begin to explain how light enters the eye. He asserted that the light ray is focused, but the actual explanation of how light projected to the back of the eye had to wait until 1604. His Treatise on Lightexplained the camera obscura, hundreds of years before the modern development of photography.[22]

Ibn al-Haytham (c. 965–c. 1040), Book of Optics Book I, [6.85], [6.86]. Book II, [3.80] describes his camera obscuraexperiments[23]

The seven-volume Book of Optics (Kitab al-Manathir) hugely influenced thinking across disciplines from the theory of visual perception to the nature ofperspective in medieval art, in both the East and the West, for more than 600 years. Many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler andIsaac Newton, were in his debt. Indeed, the influence of Ibn al-Haytham's Optics ranks alongside that of Newton's work of the same title, published 700 years later.Book of Optics (Kitab al-Manathir) hugely influenced thinking across disciplines from the theory of visual perception to the nature ofperspective in medieval art, in both the East and the West, for more than 600 years. Many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler andIsaac Newton, were in his debt. Indeed, the influence of Ibn al-Haytham's Optics ranks alongside that of Newton's work of the same title, published 700 years later.Book of Optics (Kitab al-Manathir) hugely influenced thinking across disciplines from the theory of visual perception to the nature ofperspective in medieval art, in both the East and the West, for more than 600 years. Many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler andIsaac Newton, were in his debt. Indeed, the influence of Ibn al-Haytham's Optics ranks alongside that of Newton's work of the same title, published 700 years later.

The translation of The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build devices that replicated those Ibn al-Haytham had built, and understand the way light works. From this, such important things as eyeglasses, magnifying glasses, telescopes, and cameras were developed.The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build devices that replicated those Ibn al-Haytham had built, and understand the way light works. From this, such important things as eyeglasses, magnifying glasses, telescopes, and cameras were developed.The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build devices that replicated those Ibn al-Haytham had built, and understand the way light works. From this, such important things as eyeglasses, magnifying glasses, telescopes, and cameras were developed.

Classical physics
Main article: Classical physicsSir Isaac Newton (1643–1727), whose laws of motionand universal gravitationwere 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.[24][page needed]early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics.[24][page needed]early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics.[24][page needed]

Major developments in this period include the replacement of the geocentric model of the solar system with the heliocentric Copernican model, the laws governing the motion of planetary bodies determined by Johannes Keplerbetween 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.[25] Newton also developed calculus,[c] the mathematical study of change, which provided new mathematical methods for solving physical problems.[26]geocentric model of the solar system with the heliocentric Copernican model, the laws governing the motion of planetary bodies determined by Johannes Keplerbetween 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.[25] Newton also developed calculus,[c] the mathematical study of change, which provided new mathematical methods for solving physical problems.[26]geocentric model of the solar system with the heliocentric Copernican model, the laws governing the motion of planetary bodies determined by Johannes Keplerbetween 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.[25] Newton also developed calculus,[c] the mathematical study of change, which provided new mathematical methods for solving physical problems.[26]

The discovery of new laws in thermodynamics, chemistry, andelectromagnetics resulted from greater research efforts during the Industrial Revolution as energy needs increased.[27] The laws comprising cla

Relation to other fields
This parabola-shaped lava flowillustrates the application of mathematics in physics—in this case,Galileo's law of falling bodies.Mathematics and ontology are used in physics. Physics is used in chemistry and cosmology.Prerequisites

Mathematics provides a compact and exact language used to describe the order in nature. This was noted and advocated by Pythagoras,[48] Plato,[49]Galileo,[50] and Newton.Pythagoras,[48] Plato,[49]Galileo,[50] and Newton.Pythagoras,[48] Plato,[49]Galileo,[50] and Newton.

Physics uses mathematics[51] to organise and formulate experimental results. From those results, precise or estimated solutions are obtained, quantitative results from which new predictions can be made and experimentally confirmed or negated. The results from physics experiments are numerical data, with theirunits of measure and estimates of the errors in the measurements. Technologies based on mathematics, like computation have madecomputational physics an active area of research.[51] to organise and formulate experimental results. From those results, precise or estimated solutions are obtained, quantitative results from which new predictions can be made and experimentally confirmed or negated. The results from physics experiments are numerical data, with theirunits of measure and estimates of the errors in the measurements. Technologies based on mathematics, like computation have madecomputational physics an active area of research.[51] to organise and formulate experimental results. From those results, precise or estimated solutions are obtained, quantitative results from which new predictions can be made and experimentally confirmed or negated. The results from physics experiments are numerical data, with theirunits of measure and estimates of the errors in the measurements. Technologies based on mathematics, like computation have madecomputational physics an active area of research.

The distinction between mathematics and physics is clear-cut, but not always obvious, especially in mathematical physics.

Ontology is a prerequisite for physics, but not for mathematics. It means physics is ultimately concerned with descriptions of the real world, while mathematics is concerned with abstract patterns, even beyond the real world. Thus physics statements are synthetic, while mathematical statements are analytic. Mathematics contains hypotheses, while physics contains theories. Mathematics statements have to be only logically true, while predictions of physics statements must match observed and experimental data. is a prerequisite for physics, but not for mathematics. It means physics is ultimately concerned with descriptions of the real world, while mathematics is concerned with abstract patterns, even beyond the real world. Thus physics statements are synthetic, while mathematical statements are analytic. Mathematics contains hypotheses, while physics contains theories. Mathematics statements have to be only logically true, while predictions of physics statements must match observed and experimental data. is a prerequisite for physics, but not for mathematics. It means physics is ultimately concerned with descriptions of the real world, while mathematics is concerned with abstract patterns, even beyond the real world. Thus physics statements are synthetic, while mathematical statements are analytic. Mathematics contains hypotheses, while physics contains theories. Mathematics statements have to be only logically true, while predictions of physics statements must match observed and experimental data.

The distinction is clear-cut, but not always obvious. For example, mathematical physics is the application of mathematics in physics. Its methods are mathematical, but its subject is physical.[52] The problems in this field start with a "mathematical model of a physical situation" (system) and a "mathematical description of a physical law" that will be applied to that system. Every mathematical statement used for solving has a hard-to-find physical meaning. The final mathematical solution has an easier-to-find meaning, because it is what the solver is looking for.[clarification needed][52] The problems in this field start with a "mathematical model of a physical situation" (system) and a "mathematical description of a physical law" that will be applied to that system. Every mathematical statement used for solving has a hard-to-find physical meaning. The final mathematical solution has an easier-to-find meaning, because it is what the solver is looking for.[clarification needed][52] The problems in this field start with a "mathematical model of a physical situation" (system) and a "mathematical description of a physical law" that will be applied to that system. Every mathematical statement used for solving has a hard-to-find physical meaning. The final mathematical solution has an easier-to-find meaning, because it is what the solver is looking for.[clarification needed]

Physics is a branch of fundamental science, not practical science. Physics is also called "the fundamental science" because the subject of study of all branches of natural science like chemistry, astronomy, geology, and biology are constrained by laws of physics,[53] similar to how chemistry is often called the central science because of its role in linking the physical sciences. For example, chemistry studies properties, structures, and reactions of matter (chemistry's focus on the atomic scale distinguishes it from physics). Structures are formed because particles exert electrical forces on each other, properties include physical characteristics of given substances, and reactions are bound by laws of physics, like conservation of energy, mass, and charge.fundamental science, not practical science. Physics is also called "the fundamental science" because the subject of study of all branches of natural science like chemistry, astronomy, geology, and biology are constrained by laws of physics,[53] similar to how chemistry is often called the central science because of its role in linking the physical sciences. For example, chemistry studies properties, structures, and reactions of matter (chemistry's focus on the atomic scale distinguishes it from physics). Structures are formed because particles exert electrical forces on each other, properties include physical characteristics of given substances, and reactions are bound by laws of physics, like conservation of energy, mass, and charge.fundamental science, not practical science. Physics is also called "the fundamental science" because the subject of study of all branches of natural science like chemistry, astronomy, geology, and biology are constrained by laws of physics,[53] similar to how chemistry is often called the central science because of its role in linking the physical sciences. For example, chemistry studies properties, structures, and reactions of matter (chemistry's focus on the atomic scale distinguishes it from physics). Structures are formed because particles exert electrical forces on each other, properties include physical characteristics of given substances, and reactions are bound by laws of physics, like conservation of energy, mass, and charge.

Physics is applied in industries like engineering and medicine.

Application and influence
Main article: Applied physicsArchimedes' screw, asimple machine for liftingThe application of physical laws in lifting liquids

Applied physics is a general term for physics research which is intended for a particular use. An applied physics curriculum usually contains a few classes in an applied discipline, like geology or electrical engineering. It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving a problem. is a general term for physics research which is intended for a particular use. An applied physics curriculum usually contains a few classes in an applied discipline, like geology or electrical engineering. It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving a problem. is a general term for physics research which is intended for a particular use. An applied physics curriculum usually contains a few classes in an applied discipline, like geology or electrical engineering. It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving a problem.

The approach is similar to that of applied mathematics. Applied physicists use physics in scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics.applied mathematics. Applied physicists use physics in scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics.applied mathematics. Applied physicists use physics in scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics.

Physics is used heavily in engineering. For example, statics, a subfield ofmechanics, is used in the building of bridges and other static structures. The understanding and use of acoustics results in sound control and better concert halls; similarly, the use of optics creates better optical devices. An understanding of physics makes for more realistic flight simulators, video games, and movies, and is often critical in forensic investigations.engineering. For example, statics, a subfield ofmechanics, is used in the building of bridges and other static structures. The understanding and use of acoustics results in sound control and better concert halls; similarly, the use of optics creates better optical devices. An understanding of physics makes for more realistic flight simulators, video games, and movies, and is often critical in forensic investigations.engineering. For example, statics, a subfield ofmechanics, is used in the building of bridges and other static structures. The understanding and use of acoustics results in sound control and better concert halls; similarly, the use of optics creates better optical devices. An understanding of physics makes for more realistic flight simulators, video games, and movies, and is often critical in forensic investigations.

With the standard consensus that the laws of physics are universal and do not change with time, physics can be used to study things that would ordinarily be mired in uncertainty. For example, in the study of the origin of the earth, one can reasonably model earth's mass, temperature, and rate of rotation, as a function of time allowing one to extrapolate forward or backward in time and so predict future or prior events. It also allows for simulations in engineering which drastically speed up the development of a new technology.standard consensus that the laws of physics are universal and do not change with time, physics can be used to study things that would ordinarily be mired in uncertainty. For example, in the study of the origin of the earth, one can reasonably model earth's mass, temperature, and rate of rotation, as a function of time allowing one to extrapolate forward or backward in time and so predict future or prior events. It also allows for simulations in engineering which drastically speed up the development of a new technology.standard consensus that the laws of physics are universal and do not change with time, physics can be used to study things that would ordinarily be mired in uncertainty. For example, in the study of the origin of the earth, one can reasonably model earth's mass, temperature, and rate of rotation, as a function of time allowing one to extrapolate forward or backward in time and so predict future or prior events. It also allows for simulations in engineering which drastically speed up the development of a new technology.

But there is also considerable interdisciplinarity in the physicist's methods, so many other important fields are influenced by physics (e.g., the fields ofeconophysics and sociophysics).interdisciplinarity in the physicist's methods, so many other important fields are influenced by physics (e.g., the fields ofeconophysics and sociophysics).interdisciplinarity in the physicist's methods, so many other important fields are influenced by physics (e.g., the fields ofeconophysics and sociophysics).

Research
Scientific method

Physicists use the scientific method to test the validity of a physical theory. By using a methodical approach to compare the implications of a theory with the conclusions drawn from its related experiments and observations, physicists are better able to test the validity of a theory in a logical, unbiased, and repeatable way. To that end, experiments are performed and observations are made in order to determine the validity or invalidity of the theory.[54]the scientific method to test the validity of a physical theory. By using a methodical approach to compare the implications of a theory with the conclusions drawn from its related experiments and observations, physicists are better able to test the validity of a theory in a logical, unbiased, and repeatable way. To that end, experiments are performed and observations are made in order to determine the validity or invalidity of the theory.[54]the scientific method to test the validity of a physical theory. By using a methodical approach to compare the implications of a theory with the conclusions drawn from its related experiments and observations, physicists are better able to test the validity of a theory in a logical, unbiased, and repeatable way. To that end, experiments are performed and observations are made in order to determine the validity or invalidity of the theory.[54]

A scientific law is a concise verbal or mathematical statement of a relation which expresses a fundamental principle of some theory, such as Newton's law of universal gravitation.[55]scientific law is a concise verbal or mathematical statement of a relation which expresses a fundamental principle of some theory, such as Newton's law of universal gravitation.[55]scientific law is a concise verbal or mathematical statement of a relation which expresses a fundamental principle of some theory, such as Newton's law of universal gravitation.[55]

Theory and experiment
Main articles: Theoretical physics and Experimental physicsThe astronaut and Earth are both infree-fallLightning is an electric current

Theorists seek to develop mathematical models that both agree with existing experiments and successfully predict future experimental results, whileexperimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they are strongly dependent upon each other. Progress in physics frequently comes about when experimentalists make a discovery that existing theories cannot explain, or when new theories generate experimentally testablepredictions, which inspire new experiments.[56]mathematical models that both agree with existing experiments and successfully predict future experimental results, whileexperimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they are strongly dependent upon each other. Progress in physics frequently comes about when experimentalists make a discovery that existing theories cannot explain, or when new theories generate experimentally testablepredictions, which inspire new experiments.[56]mathematical models that both agree with existing experiments and successfully predict future experimental results, whileexperimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they are strongly dependent upon each other. Progress in physics frequently comes about when experimentalists make a discovery that existing theories cannot explain, or when new theories generate experimentally testablepredictions, which inspire new experiments.[56]

Physicists who work at the interplay of theory and experiment are calledphenomenologists, who study complex phenomena observed in experiment and work to relate them to a fundamental theory.[57] who work at the interplay of theory and experiment are calledphenomenologists, who study complex phenomena observed in experiment and work to relate them to a fundamental theory.[57] who work at the interplay of theory and experiment are calledphenomenologists, who study complex phenomena observed in experiment and work to relate them to a fundamental theory.[57]

Theoretical physics has historically taken inspiration from philosophy;electromagnetism was unified this way.[d] Beyond the known universe, the field of theoretical physics also deals with hypothetical issues,[e] such as parallel universes, a multiverse, and higher dimensions. Theorists invoke these ideas in hopes of solving particular problems with existing theories. They then explore the consequences of these ideas and work toward making testable predictions.electromagnetism was unified this way.[d] Beyond the known universe, the field of theoretical physics also deals with hypothetical issues,[e] such as parallel universes, a multiverse, and higher dimensions. Theorists invoke these ideas in hopes of solving particular problems with existing theories. They then explore the consequences of these ideas and work toward making testable predictions.electromagnetism was unified this way.[d] Beyond the known universe, the field of theoretical physics also deals with hypothetical issues,[e] such as parallel universes, a multiverse, and higher dimensions. Theorists invoke these ideas in hopes of solving particular problems with existing theories. They then explore the consequences of these ideas and work toward making testable predictions.

Experimental physics expands, and is expanded by, engineering andtechnology. Experimental physicists involved in basic research design and perform experiments with equipment such as particle accelerators and lasers, whereas those involved in applied research often work in industry developing technologies such as magnetic resonance imaging (MRI) and transistors.Feynman has noted that experimentalists may seek areas which are not well-explored by theorists.[58] physics expands, and is expanded by, engineering andtechnology. Experimental physicists involved in basic research design and perform experiments with equipment such as particle accelerators and lasers, whereas those involved in applied research often work in industry developing technologies such as magnetic resonance imaging (MRI) and transistors.Feynman has noted that experimentalists may seek areas which are not well-explored by theorists.[58] physics expands, and is expanded by, engineering andtechnology. Experimental physicists involved in basic research design and perform experiments with equipment such as particle accelerators and lasers, whereas those involved in applied research often work in industry developing technologies such as magnetic resonance imaging (MRI) and transistors.Feynman has noted that experimentalists may seek areas which are not well-explored by theorists.[58]

Scope and aims
Physics involves modeling the natural world with theory, usually quantitative. Here, the path of a particle is modeled with the mathematics of calculus to explain its behavior: the purview of the branch of physics known as mechanics.

Physics covers a wide range of phenomena, from elementary particles (such as quarks, neutrinos, and electrons) to the largest superclusters of galaxies. Included in these phenomena are the most basic objects composing all other things. Therefore, physics is sometimes called the "fundamental science".[53]Physics aims to describe the various phenomena that occur in nature in terms of simpler phenomena. Thus, physics aims to both connect the things observable to humans to root causes, and then connect these causes together.phenomena, from elementary particles (such as quarks, neutrinos, and electrons) to the largest superclusters of galaxies. Included in these phenomena are the most basic objects composing all other things. Therefore, physics is sometimes called the "fundamental science".[53]Physics aims to describe the various phenomena that occur in nature in terms of simpler phenomena. Thus, physics aims to both connect the things observable to humans to root causes, and then connect these causes together.phenomena, from elementary particles (such as quarks, neutrinos, and electrons) to the largest superclusters of galaxies. Included in these phenomena are the most basic objects composing all other things. Therefore, physics is sometimes called the "fundamental science".[53]Physics aims to describe the various phenomena that occur in nature in terms of simpler phenomena. Thus, physics aims to both connect the things observable to humans to root causes, and then connect these causes together.

For example, the ancient Chinese observed that certain rocks (lodestone andmagnetite) were attracted to one another by an invisible force. This effect was later called magnetism, which was first rigorously studied in the 17th century. But even before the Chinese discovered magnetism, the ancient Greeks knew of other objects such as amber, that when rubbed with fur would cause a similar invisible attraction between the two.[59] This was also first studied rigorously in the 17th century and came to be called electricity. Thus, physics had come to understand two observations of nature in terms of some root cause (electricity and magnetism). However, further work in the 19th century revealed that these two forces were just two different aspects of one force—electromagnetism. This process of "unifying" forces continues today, and electromagnetism and the weak nuclear force are now considered to be two aspects of theelectroweak interaction. Physics hopes to find an ultimate reason (Theory of Everything) for why nature is as it is (see section Current research below for more information).[60]ancient Chinese observed that certain rocks (lodestone andmagnetite) were attracted to one another by an invisible force. This effect was later called magnetism, which was first rigorously studied in the 17th century. But even before the Chinese discovered magnetism, the ancient Greeks knew of other objects such as amber, that when rubbed with fur would cause a similar invisible attraction between the two.[59] This was also first studied rigorously in the 17th century and came to be called electricity. Thus, physics had come to understand two observations of nature in terms of some root cause (electricity and magnetism). However, further work in the 19th century revealed that these two forces were just two different aspects of one force—electromagnetism. This process of "unifying" forces continues today, and electromagnetism and the weak nuclear force are now considered to be two aspects of theelectroweak interaction. Physics hopes to find an ultimate reason (Theory of Everything) for why nature is as it is (see section Current research below for more information).[60]ancient Chinese observed that certain rocks (lodestone andmagnetite) were attracted to one another by an invisible force. This effect was later called magnetism, which was first rigorously studied in the 17th century. But even before the Chinese discovered magnetism, the ancient Greeks knew of other objects such as amber, that when rubbed with fur would cause a similar invisible attraction between the two.[59] This was also first studied rigorously in the 17th century and came to be called electricity. Thus, physics had come to understand two observations of nature in terms of some root cause (electricity and magnetism). However, further work in the 19th century revealed that these two forces were just two different aspects of one force—electromagnetism. This process of "unifying" forces continues today, and electromagnetism and the weak nuclear force are now considered to be two aspects of theelectroweak interaction. Physics hopes to find an ultimate reason (Theory of Everything) for why nature is as it is (see section Current research below for more information).[60]

Research fields

Contemporary research in physics can be broadly divided into nuclear andparticle physics; condensed matter physics; atomic, molecular, and optical physics; astrophysics; and applied physics. Some physics departments also support physics education research and physics outreach.[61]nuclear andparticle physics; condensed matter physics; atomic, molecular, and optical physics; astrophysics; and applied physics. Some physics departments also support physics education research and physics outreach.[61]nuclear andparticle physics; condensed matter physics; atomic, molecular, and optical physics; astrophysics; and applied physics. Some physics departments also support physics education research and physics outreach.[61]

Since the 20th century, the individual fields of physics have become increasingly specialised, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) andLev Landau (1908–1968), who worked in multiple fields of physics, are now very rare.[f]specialised, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) andLev Landau (1908–1968), who worked in multiple fields of physics, are now very rare.[f]specialised, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) andLev Landau (1908–1968), who worked in multiple fields of physics, are now very rare.[f]

The major fields of physics, along with their subfields and the theories and concepts they employ, are shown in the following table.

FieldSubfieldsMajor theoriesConceptsNuclear andparticle physicsNuclear physics,Nuclear astrophysics,Particle physics,Particle astrophysics,Particle physics phenomenologyStandard Model,Quantum field theory,Quantum electrodynamics,Quantum chromodynamics,Electroweak theory,Effective field theory,Lattice field theory,Lattice gauge theory,Gauge theory,Supersymmetry, Grand unification theory,Superstring theory, M-theoryFundamental force(gravitational,electromagnetic,weak, strong),Elementary particle,Spin, Antimatter,Spontaneous symmetry breaking,Neutrino oscillation,Seesaw mechanism,Brane, String,Quantum gravity,Theory of everything,Vacuum energyAtomic, molecular, and optical physicsAtomic physics,Molecular physics, Atomic and Molecular astrophysics,Chemical physics, Optics,PhotonicsQuantum optics,Quantum chemistry,Quantum information sciencePhoton, Atom,Molecule, Diffraction,Electromagnetic radiation, Laser,Polarization (waves),Spectral line, Casimir effectCondensed matter physicsSolid state physics, High pressure physics, Low-temperature physics,Surface Physics,Nanoscale and Mesoscopic physics,Polymer physicsBCS theory, Bloch wave,Density functional theory, Fermi gas, Fermi liquid, Many-body theory, Statistical MechanicsPhases (gas, liquid,solid), Bose-Einstein condensate,Electrical conduction,Phonon, Magnetism,Self-organization,Semiconductor,superconductor,superfluid, Spin,AstrophysicsAstronomy,Astrometry,Cosmology,Gravitation physics, High-energy astrophysics,Planetary astrophysics,Plasma physics, Solar physics, Space physics, Stellar astrophysicsBig Bang, Cosmic inflation, General relativity, Newton's law of universal gravitation,Lambda-CDM model,MagnetohydrodynamicsBlack hole, Cosmic background radiation, Cosmic string, Cosmos, Dark energy, Dark matter,Galaxy, Gravity,Gravitational radiation,Gravitational singularity, Planet,Solar System, Star,Supernova, UniverseApplied PhysicsAccelerator physics, Acoustics, Agrophysics, Biophysics,Chemical Physics, Communication Physics, Econophysics,Engineering physics, Fluid dynamics, Geophysics, Laser Physics, Materials physics, Medical physics, Nanotechnology,Optics, Optoelectronics, Photonics, Photovoltaics, Physical chemistry, Physics of computation, Plasma physics, Solid-state devices, Quantum chemistry, Quantum electronics, Quantum information science, Vehicle dynamics