Magnetism
A magnetic quadrupole Magnetism is a class of physical phenomena that includes forces exerted by magnets on other magnets. It has its origin in electric currents and the fundamental magnetic moments of elementary particles. These give rise to a magnetic field that acts on other currents and moments. All materials are influenced to some extent by a magnetic field. The magnetic state (or phase) of a material depends on temperature (and other variables such as pressure and the applied magnetic field) so that a material may exhibit more than one form of magnetism depending on its temperature, etc. History[edit] In ancient China, the earliest literary reference to magnetism lies in a 4th-century BC book named after its author, The Master of Demon Valley (鬼谷子): "The lodestone makes iron come or it attracts it Alexander Neckam, by 1187, was the first in Europe to describe the compass and its use for navigation. Michael Faraday, 1842 Sources of magnetism[edit] Topics[edit] Diamagnetism[edit]
Math and Physics Java Applets by Paul Falstad
Oscillations and Waves Acoustics Signal Processing Electricity and Magnetism: Statics Electrodynamics Quantum Mechanics Linear Algebra Vector Calculus Thermodynamics Mechanics Miscellaneous Licensing info. Links to other educational sites with math/physics-related information or java applets useful for teaching: And when you get tired of learning, here is some fun stuff: Pong Simulation Circuit-level simulation of original 1972 Pong.
History of electromagnetism
The history of electromagnetic theory begins with ancient measures to deal with atmospheric electricity, in particular lightning.[1] People then had little understanding of electricity, and were unable to scientifically explain the phenomena.[2] In the 19th century there was a unification of the history of electric theory with the history of magnetic theory. It became clear that electricity should be treated jointly with magnetism, because wherever electricity is in motion, magnetism is also present.[3] Magnetism was not fully explained until the idea of magnetic induction was developed.[4] Electricity was not fully explained until the idea of electric charge was developed. Ancient and classical history[edit] The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. Middle Ages and the Renaissance[edit]
Standard Model
The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, as well as classifying all the subatomic particles known. It was developed throughout the latter half of the 20th century, as a collaborative effort of scientists around the world.[1] The current formulation was finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the top quark (1995), the tau neutrino (2000), and more recently the Higgs boson (2013), have given further credence to the Standard Model. Although the Standard Model is believed to be theoretically self-consistent[2] and has demonstrated huge and continued successes in providing experimental predictions, it does leave some phenomena unexplained and it falls short of being a complete theory of fundamental interactions. Historical background[edit] Overview[edit] Particle content[edit] Fermions[edit] Gauge bosons[edit] Higgs boson[edit] Challenges[edit]
Periodic table
Standard 18-column form of the periodic table. The colors used in the version of the table shown here signify different categories of elements, as listed below in the Layout section, under the larger table. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table. All elements from atomic numbers 1 (hydrogen) to 118 (ununoctium) have been discovered or reportedly synthesized, with elements 113, 115, 117 and 118 having yet to be confirmed. Layout Grouping methods Groups A group or family is a vertical column in the periodic table.
Weak interaction
In particle physics, the weak interaction is the mechanism responsible for the weak force or weak nuclear force, one of the four fundamental interactions of nature, alongside the strong interaction, electromagnetism, and gravitation. The weak interaction is responsible for both the radioactive decay and nuclear fusion of subatomic particles. The theory of the weak interaction is sometimes called quantum flavordynamics (QFD), in analogy with the terms QCD and QED, but in practice the term is rarely used because the weak force is best understood in terms of electro-weak theory (EWT).[1] During the quark epoch, the electroweak force split into the electromagnetic and weak force. History[edit] In 1933, Enrico Fermi proposed the first theory of the weak interaction, known as Fermi's interaction. However it is better described as a non-contact force field having a finite range, albeit very short. The existence of the W and Z bosons was not directly confirmed until 1983. Properties[edit]
Hertz
"Megahertz", "MHz", "Gigahertz" and "GHz" redirect here. Top to bottom: Lights flashing at frequenciesf = 0.5 Hz (hertz), 1.0 Hz and 2.0 Hz, i.e. at 0.5, 1.0 and 2.0 flashes per second, respectively. The time between each flash – the period T – is given by 1⁄f (the reciprocal of f), i.e. 2, 1 and 0.5 seconds, respectively. The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. One of the unit's most common uses is in the description of sine waves and musical tones, particularly those used in radio and other audio-related applications. Definition[edit] In English, "hertz" is also used as the plural form.[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 103 Hz), MHz (megahertz, 106 Hz), GHz (gigahertz, 109 Hz) and THz (terahertz, 1012 Hz). and History[edit]
Electroencephalography
From Wikipedia, the free encyclopedia Brain wave may refer to: Arts[edit] Neuroscience[edit] Organizations[edit] Epilepsy Ireland, an organisation formerly known as "Brainwave – The Irish Epilepsy Association"
AFI – Discover music, videos, concerts, & pictures at Last.fm
Linkin Park – Discover music, videos, concerts, & pictures at La
