Tuesday, April 9, 2019
Physics in the Past Essay Example for Free
Physics in the Past quizOne hundred days ago, in a poky apartment in Bern, Switzerland, Albert mind, then merely if a 26-year-old patent office clerk restrained working part-time towards his PhD, published five terra firma breaking scientific papers. Each of these papers, written during Einsteins annus mirabilis , has become a classic in the account statement of science On a Heuristic Viewpoint Concerning the Production and Transformation of Light , which discusses optical photons and photoelectric effects. Molecular and New Measurement , which deduces the mathematical equation for calculating the speed of the diffusion of molecules. On the exercise of Small Particles Suspended in Stationary Liquids Required by the Molecular-Kinetic Theory of Heat , which provides proof for the beingness of pinchs. Does the Inertia of a Body Depend upon its Internal Energy, which proposes the idea for two-way transformation between survey and readiness according to the special syst em of theory of theory of relativity. On the Electrodynamics of pitiable Bodies , which proposes a sore theory on the race between time and space. This paper served as the foundation for the theory of relativity.The contemporary physics revolution, ground on the theory of relativity and quantum theory, has led science into a new era. Starting from this, human exploration has extended to the boundless universe, to the distant origin of the cosmos and to the microscopic structure of objects previously unknown to mankind. modern-day physics revolution has as well spurred revolution in life sciences and geosciences in the last years. All these collect changed mankinds outlook on matter, time, space, life and the universe.Moreover, this contemporary physics revolution has also given birth to scientific physics including nuclear zilch, semiconductors, laser, new materials much(prenominal) as with superconductivity, and fostered rapid knowledge of a wide grade of new technolo gies that have changed the methods of our industrial production and our ways of life part bringing the world to the new knowledge economics era. Founders of contemporary physics, Einstein the most outstanding among them, are undoubtedly epoch figures in the history of science and the history of mankind.It is in that heedfore both(prenominal)(prenominal) of signifi flockce and importance for us to commemorate them in our reflections on the development of physics in the last ace hundred years not exactly to express our gratitude that to draw inspiration from their achievements and build on their legacy to create a discover future for all humankind. 1. The inconsistency between experiments and theories gave birth to new science concepts At the end of the 19 th century, people were still intoxicated with the interpretations given by classical physics. Some even held that there was not much more to do in physics.It was under such a state that the denudation of some physical phe nomena revealed the limitations of interpretations given by classical physics. High-temperature measurement technology, called for by the rapid development of the metallurgical industry, led to explore in thermal radiation. In the mid 19 th century, Germ whatsoever emerged as the cradle for seek in this playing area. Thermal radiation refers to the electromagnetic wavers emitted by matter when heated and largely seems on the temperature of the matter itself. Maxwells electromagnetic business line theory regards light as an electromagnetic phenomenon.Although this informs the propagation of light, it does not explain the emission and reception of thermal radiation. G. R. Kirchhoff (18241887) advanced to use dark be as an ideal body for research on thermal radiation (1859). W. Wien (1864-1928) confirmed that it is possible to regard the thermal radiation achievement of a pored cavity as a black body (1896). A series of experiments demonstrated that the tautness of the vim emitted by such black body is related to its temperature and not to its shape or materials. metaphysical explanation of the energy spectrum curve of a black body became an essential issue in research on thermal radiation at the time. base on the general principle of thermal mechanics and some special assumptions, Wien certain a formula to determine the energy density associated with particular wavelengths for any given temperature of a radiating black body (1896). Max Plank joined research on heat radiation during the same period. To explain the energy distribution curve of the radiated light spectrum of a black body, Plank developed a formula.It was not until 1900 that scientists proved the veracity of the formula through experimentation. Plancks formula requires that the energy emitted or absorbed by black body is the energy quanta that determine its amount. This implies that energy, like a matter, has the properties of particles, i. e. , energy also has separability and discre teness. In 1905, Einstein extended the concept of quanta to the propagation of light and proposed the light quantum theory, successfully use it to explain photoelectric effect.In 1913, the Danish physicist N.Bohr (1885 1962) extended the concept of quanta to atoms, and established a quantum structural instance for atoms based on the discreteness hypothesis of the energy state of atoms. Dissatisfied with the lack of self- sufficiency of Bohrs atom theory, the German physicist Werner Karl Heisenberg (19011976) developed matrix mechanics in 1925 by offset directly from a priori info on the frequency and intensity of spectrum of visible light. The following year, the Austrian physicist E. Schr? dinger (18921961) improved the wave-particle duality matter wave theory of L. V. de Broglie (18921994), leading to wave mechanics.Subsequent research proved the mathematical equivalence of both matrix mechanics and wave mechanics. The American physicist R. P. Feynman (1918 1988) later devel oped the third equivalent path organic quantum mechanics. It is until this period of time that quantum theory was established to its robust architecture. The thermal radiation hypothesis became the logical starting point for the birth of quantum theory. The quantum of energy concept was developed in 1900. As a result of its development and extended application, quantum mechanics, which describes the motion of subatomic particles, took form in the 1920s.The combination of quantum mechanics with the special theory of relativity gave birth to quantum field theory, which describes the generation and annihilation of subatomic particles. Development of quantum field theory has experienced tierce stages classical quantum field theory (symmetrical), standard quantum field theory (non-symmetrical) and super-symmetrical quantum field theory. It has not only revealed the secrets of the subatomic world invisible to the naked eye, but deepened our understanding of the evolution of the univers e and revolutionized the way people discriminate the world.Quantum field theory, moreover, has set the stage for a series of notice technological breakthroughs. It has been demonstrated from the data-based research on a black body radiation to the advancement of the quantum theory that science is, after all, still a positivistic knowledge system. That is, as long as a theory is not agreeable with rigorous experimental results, a scientist has all the reasons to doubt the theory itself no matter how authoritative the theory it may be, no matter how many people have upheld it, and no matter how many years it has been embraced.At the same time, we should understand that the ultimate results of scientific research should give theoretical interpretation of raw(a) phenomena discovered while this requires not only rigorous and scientific attitude and rational challenging spirit, but also profound thinking ability and deliberate analysis ability and theoretical reasoning ability. 2. ma ke breakthroughs in science hinge upon distillation of scientific research psyches The theory of relativity advanced by Albert Einstein (1879 1955) is a brand new outlook on space and time. The key scientific question for the theory of relativity lies in simultaneous relativity.The theory of relativity has given justified interpretations about the relationship between time and space, the relationship between space and distribution of matters, and the relationship between matters and energy. In the process, it alter the knowledge system of classical physics dating back to Sir Isaac Newton(1642-1727). The theory of relativity, together with quantum theory, not only formed the foundation for development of physics in the 20 th century but also raised our understanding of the nature to an entirely new level, thus having a profound effect on the way of thinking and perceptions of the world.The founding of the theory of relativity originated from the crisis of ethyl ether, a hypothesi zed carrier for electromagnetic waves. The experiment subject On the Relative Motion between the Earth and Light Ether published by the American physicist A. A. Michelson (18521931), revealed that the theory of relativity, which is universally correct in the reference to Newtonian mechanics, is incorrect in Maxwells electromagnetic field theory. Both the Dutch physicist H. A. Lorentz (18531928) and the French physicist J. H. Poincare (18541912) attempted to solve this contradiction by maintaining the Ether hypothesis.Lorentz proved that the reason system and Ether follow the same law at the first-order approximation by incorporating length muscle contraction (1892), regional time (1895) and a new conversion relationship (1904) while the relativity principle developed by Poincare and the conversion group (1905) developed by Lorentz emphasized the universal validity of the relativity principle. Although both deviated from the framework of classical physics lay at the doorstep to th e theory of relativity,but it was left to Albert Einstein to uprise the key and push the door open.Einstein believed that the electromagnetic field had an in numerateent physical existence and held the Ether hypothesis to be superfluous. His most important contribution may reside inside in the accompaniment that he raised the critical scientific problem of simultaneous relativity. In On the Electrodynamics of Moving Bodies (1905), Einstein claimed that two events happening simultaneously in the same location do not depend on the observations of the observers yet two events happening simultaneously at two different locations do depend on their observations.It would be meaningful only if it is indicated clearly that the events are relative to which observer. We could hardly observe such relativity of simultaneity in our daily lives because this can be discovered only when the speed of an observer is close to the speed of light. Starting from the simultaneity of relativity concept, Einstein deducted the main conclusions for the theory of special relativity through two principles constancy of the speed of light and relativity.The general theory of relativity (1915) and the unified field theory are win developments of the theory of special relativity. Through his trilogy research on the theory of relativity, Einstein revealed to his physics colleagues his extraordinary creativity in scientific thinking. 3. Scientific imagination requires the support of rigorous experimental proof In the year following the publication of his general theory, Einstein publishedObservations Made on cosmology Based on the General Theory of Relativity (1917), which marked the birth of modern cosmology.Although Einsteins cosmological shape followed the static Newtonian view on the universe, its field theory lays the groundwork for the existence of dynamic solutions to cosmology. The Dutch astronomer W. de Sitter (1878-1933), the Russian mathematician A. Friedmann(1888-1925) and the Belgian physicist G. Lemaitre(18941966) published the expanding universe theory in 1917, 1922 and 1927, respectively. The red charge up effect observed by the American astronomer Edwin Hubble (1889-1953) offered strong support for the expanding universe theory.Drawing on the expanding universe theory, the Russian American physicist G. Gamov (19041968), formulated the idea of a hot explosion of matter and energy at the time of the origin of the universe by incorporating knowledge in nuclear physics. His student R. A. Alpher(1921-) and others further derived in 1948, that the man-sized bang explosion took place about 15 trillion to 20 billion years ago and hypothesized that remains from the big bang explosion may still be move in the universe, presenting 5K cosmological background radiation.In 1964, two American radio engineers, A.A. Penzias (1933-) and R. W. Wilson (1936-), discovered evenly distributed isotropous cosmic microwave background radiation while tracing the source of radio noise that was meddlesome with the development of a communications program involving satellites. This microwave radiation is coincidentally equivalent to 3. 5K blackbody radiation. This uncovering is regarded as a confirmation of the cosmic background radiation as a result of the big bang explosion. The latter years witnessed the rise of the big bang theory, which developed as the standard precedent for cosmology.In the early of 20 th century, Einstein listed the origin of a geomagnetic field as single of the five major challenges in physics. However, not until the 1960s, after the unstable wave method confirmed the forge structure of the earth, did scientists devise the self-exciting dynamo hypothesis, the full scientific endorsement of which awaited evidence from differential core-mantle movement obtained in 1995. Increased knowledge on the inner structure of the solid earth mainly relies on the seismic wave method.The concept of mold structure of the earth has gradu ally formed through analysis of magnetic variation of the seismic wave passing through the inner structure of the earth. The Croatian geophysicist, A. Mohorovi? ie (18571936), discovered the interface between the earths crust and mantle (1909) The German-American seismologist, B. Gutenberg (18891960), discovered the interface between the earths mantle and the core (1914) and the Dutch seismologist I. Lehmann discovered the interface between the earths liquid outer and solid inner core (1914).The New Zealander physicist K. E. Bullen proposed the layered model of the earth (1940). The differential core-mantle revolving movement, a hypothesis designed to explain the origin of the geomagnetic field, was later apply as a mechanism to explain the inversion of the polarity of geomagnetism. However, no direct scientific evidence had been found. Based on their analysis of recorded data for 38 earthquakes, which took place between 1967 to 1995 near the machinate Islands close to the South Pole in South America, Dawn (Xiaodong) Song and Paul G.Richards, Columbia University, in US, measured the speed of seismic wave transmitted from the earths inner core to a seismographic station in Alaska near the labor union Pole.They found that the time it took seismic wave to travel from the South Pole to the North Pole had been reduced by 0. 3 seconds over the previous years. This confirms that the earths inner core is revolving slightly fast than its crust and the mantleindeed the earths inner core will turn one extra luck in about 300 to 400 years. Dr.Su Weijia, another Chinese scholar residing in the US, and Dziewonski, an American seismologist, reached a similar conclusion based on analyses of seismic data from about 2000 seismographic stations around the globe. Based on their computation, the revolving speed of the earths inner core is even faster, 20 30 degrees just over the timeframe 1969 to 1973. It can be seen from the propositions and improvement of the theory of r elativity by Einstein, the big bang theory and the geomagnetic theory that while it is important to solve problems in development of science, it seems even more important to raise key questions in science.Raising questions is the prelude to scientific research. More importantly, raising key questions reveals the creativity associated with science. Sometimes a key question in science leads to new fields and new research directions. To ask the right questions, one must have a through understanding of existing knowledge, a love for truth that transcends respect for authority, and fine observational skills and creative thinking. At the same time, one must be rational boldface and confident.