TMS Fridge Poetry | Magnetic Words - Novelty Words, Gift, Present, Poem, Muse, Magnet (Original I)

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Heating a magnet past its Curie temperature; the molecular motion destroys the alignment of the magnetic domains. This always removes all magnetization.

In all units, it is convenient to employ two types of magnetic field, B and H, as well as the magnetization M, defined as the magnetic moment per unit volume.Older types of televisions (non flat screen) and older large computer monitors: TV and computer screens containing a cathode ray tube employ an electromagnet to guide electrons to the screen. [27] The United States Department of Energy has identified a need to find substitutes for rare-earth metals in permanent-magnet technology, and has begun funding such research. The Advanced Research Projects Agency-Energy (ARPA-E) has sponsored a Rare Earth Alternatives in Critical Technologies (REACT) program to develop alternative materials. In 2011, ARPA-E awarded 31.6 million dollars to fund Rare-Earth Substitute projects. [39] Iron nitrides are promising materials for rare-earth free magnets. [40] Costs Science projects: Many topic questions are based on magnets, including the repulsion of current-carrying wires, the effect of temperature, and motors involving magnets. [28] Hammering or jarring: mechanical disturbance tends to randomize the magnetic domains and reduce magnetization of an object, but may cause unacceptable damage. Placing the item in an external magnetic field will result in the item retaining some of the magnetism on removal. Vibration has been shown to increase the effect. Ferrous materials aligned with the Earth's magnetic field that are subject to vibration (e.g., frame of a conveyor) have been shown to acquire significant residual magnetism. Likewise, striking a steel nail held by fingers in a N-S direction with a hammer will temporarily magnetize the nail.

Electric Current: The magnetic field produced by passing an electric current through a coil can get domains to line up. Once all of the domains are lined up, increasing the current will not increase the magnetization. [33] Another model is the Ampère model, where all magnetization is due to the effect of microscopic, or atomic, circular bound currents, also called Ampèrian currents, throughout the material. For a uniformly magnetized cylindrical bar magnet, the net effect of the microscopic bound currents is to make the magnet behave as if there is a macroscopic sheet of electric current flowing around the surface, with local flow direction normal to the cylinder axis. [18] Microscopic currents in atoms inside the material are generally canceled by currents in neighboring atoms, so only the surface makes a net contribution; shaving off the outer layer of a magnet will not destroy its magnetic field, but will leave a new surface of uncancelled currents from the circular currents throughout the material. [19] The right-hand rule tells which direction positively-charged current flows. However, current due to negatively-charged electricity is far more prevalent in practice. [ citation needed] Polarity Medicine: Hospitals use magnetic resonance imaging to spot problems in a patient's organs without invasive surgery.Magnets may be used to serve as a fail-safe device for some cable connections. For example, the power cords of some laptops are magnetic to prevent accidental damage to the port when tripped over. The MagSafe power connection to the Apple MacBook is one such example. Stroking: An existing magnet is moved from one end of the item to the other repeatedly in the same direction ( single touch method) or two magnets are moved outwards from the center of a third ( double touch method). [32] There are various other types of magnetism, such as spin glass, superparamagnetism, superdiamagnetism, and metamagnetism. Magnets have many uses in toys. M-tic uses magnetic rods connected to metal spheres for construction.

The term magnet is typically reserved for objects that produce their own persistent magnetic field even in the absence of an applied magnetic field. Only certain classes of materials can do this. Most materials, however, produce a magnetic field in response to an applied magnetic field – a phenomenon known as magnetism. There are several types of magnetism, and all materials exhibit at least one of them.Common uses Hard disk drives record data on a thin magnetic coating Magnetic hand separator for heavy minerals The maximum usable temperature is highest for alnico magnets at over 540°C (1,000°F), around 300°C (570°F) for ferrite and SmCo, about 140°C (280°F) for NIB and lower for flexible ceramics, but the exact numbers depend on the grade of material.

For most engineering applications, MKS (rationalized) or SI (Système International) units are commonly used. Two other sets of units, Gaussian and CGS-EMU, are the same for magnetic properties and are commonly used in physics. [ citation needed] If a ferromagnetic foreign body is present in human tissue, an external magnetic field interacting with it can pose a serious safety risk. [30] The magnetic field H is given in SI units of ampere-turns per meter (A-turn/m). The turns appear because when H is produced by a current-carrying wire, its value is proportional to the number of turns of that wire. In CGS, the unit of H is the oersted (Oe). One A-turn/m equals 4π×10 −3 Oe.Classically, the force between two magnetic poles is given by: [47] F = μ q m 1 q m 2 4 π r 2 {\displaystyle F={{\mu q_{m1}q_{m2}} \over {4\pi r A wire in the shape of a circle with area A and carrying current I has a magnetic moment of magnitude equal to IA. Magnetic levitation transport, or maglev, is a form of transportation that suspends, guides and propels vehicles (especially trains) through electromagnetic force. Eliminating rolling resistance increases efficiency. The maximum recorded speed of a maglev train is 581 kilometers per hour (361mph).