darrin black
Help. Cool stuff. Synzen’s Music Profile. Tiger Army – Discover music, videos, concerts, & pictures at Las. Hellcatrecords's Channel. Linkin Park – Discover music, videos, concerts, & pictures at La. Linkinparktv's Channel. DJ Krush – Discover music, videos, concerts, & pictures at Last. DJ Shadow – Discover music, videos, concerts, & pictures at Last. Djshadow's Channel. Sneaker Pimps – Discover music, videos, concerts, & pictures at. AFI – Discover music, videos, concerts, & pictures at Last.fm. Afireinside's Channel. 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. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences.
Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table. Layout Grouping methods Groups Periods Blocks Categories Atomic radii. 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.
Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a "theory of almost everything". Historical background[edit] The Higgs mechanism is believed to give rise to the masses of all the elementary particles in the Standard Model. Overview[edit] Particle content[edit] Fermions[edit] Gauge bosons[edit] Higgs boson[edit] Main article: Higgs boson E.S. Electron. History[edit] In the early 1700s, Francis Hauksbee and French chemist Charles François de Fay independently discovered what they believed were two kinds of frictional electricity—one generated from rubbing glass, the other from rubbing resin. From this, Du Fay theorized that electricity consists of two electrical fluids, vitreous and resinous, that are separated by friction, and that neutralize each other when combined.[17] A decade later Benjamin Franklin proposed that electricity was not from different types of electrical fluid, but the same electrical fluid under different pressures.
He gave them the modern charge nomenclature of positive and negative respectively.[18] Franklin thought of the charge carrier as being positive, but he did not correctly identify which situation was a surplus of the charge carrier, and which situation was a deficit.[19] Discovery[edit] A beam of electrons deflected in a circle by a magnetic field[25] Robert Millikan Atomic theory[edit] Electromagnetism. 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 strongest effect is on permanent magnets, which have persistent magnetic moments caused by ferromagnetism. Most materials do not have permanent moments. Some are attracted to a magnetic field (paramagnetism); others are repulsed by a magnetic field (diamagnetism); others have a much more complex relationship with an applied magnetic field (spin glass behavior and antiferromagnetism). 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. 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"
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. It is also used to describe the speeds at which computers and other electronics are driven. Definition[edit] and This SI unit is named after Heinrich Hertz. History[edit] Applications[edit] Vibration[edit] Electromagnetic radiation[edit] Computers[edit] 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. Most fermions will decay by a weak interaction over time.
Important examples include beta decay, and the production of deuterium and then helium from hydrogen that powers the sun's thermonuclear process. History[edit] The existence of the W and Z bosons was not directly confirmed until 1983. Properties[edit] 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]