Get a decent size magnet. Get some iron filaments and sprinkle the iron filaments around the magnet. You will see the magnetic field of the magnet from the iron filaments lining up from each pole and curving outwards.
Your magnetic compass does not actually point north, it merely aligns itself with the lines of magnetic force at your location. These do not necessarily point to the North - they may differ by some tens of degrees. This difference is the Magnetic Declination. On hikers maps, you'll find that the true north of the map is shown as well as the magnetic declination at that region. The declination itself changes slowly, too slow for you to bother with its changing.
A remote reading compass uses a remote detector to determine the heading to be shown on the compass indicator on the pilot's instrument panel. The detector will be a Flux Detector/or flux gate and consists of a pendulous set of 4 coils aranged on a three leg "spider" One of the coils is the excitation coil supplied with 26V 400 HZ AC while the other three have an induced ac voltage from the excitation. Depending where they lie realative to the earth's magnetic field their output voltage will be either assisted or hindered and there will be an electric field created in the the three output wires which can drive an indicator to display the aircraft magnetic heading . These Indicators will be usually a HSI ( Horrizontal Situation Indicator) PNI ( Pictorial Navigation Indicator) or RMI (Radio Magnetic Indicator) Usually the output signal from the Flux detector is so small that an amplifier is needed to boost the signel to the Indicator. This system is usually GYRO STADILISED ( Directional Gyro) to make it display accurately in turns and to make it wander less. If it is not fitted with a gyro then the system is called a NON GYRO STABILISED REMOTE READING COMPASS system. It still workes but the display is more inclined to wander.
Futuristic ideas for the use of superconductors, materials that allow electric current to flow without resistance, are myriad: long-distance, low-voltage electric grids with no transmission loss; fast, magnetically levitated trains; ultra-high-speed supercomputers; superefficient motors and generators; inexhaustible fusion energy - and many others, some in the experimental or demonstration stages.But superconductors, especially superconducting electromagnets, have been around for a long time. Indeed the first large-scale application of superconductivity was in particle-physics accelerators, where strong magnetic fields steer beams of charged particles toward high-energy collision points.Accelerators created the superconductor industry, and superconducting magnets have become the natural choice for any application where strong magnetic fields are needed - for magnetic resonance imaging (MRI) in hospitals, for example, or for magnetic separation of minerals in industry. Other scientific uses are numerous, from nuclear magnetic resonance to ion sources for cyclotrons.Some of the strongest and most complex superconducting magnets are still built for particle accelerators like CERN's Large Hadron Collider (LHC). The LHC uses over 1,200 dipole magnets, whose two adjacent coils of superconducting cable create magnetic fields that bend proton beams traveling in opposite directions around a tunnel 27 kilometers in circumference; the LHC also has almost 400 quadrupole magnets, whose coils create a field with four magnetic poles to focus the proton beams within the vacuum chamber and guide them into the experiments.These LHC magnets use cables made of superconducting niobium titanium (NbTi), and for five years during its construction the LHC contracted for more than 28 percent of the world's niobium titanium wire production, with significant quantities of NbTi also used in the magnets for the LHC's giant experiments.What's more, although the LHC is still working to reach the energy for which it was designed, the program to improve its future performance is already well underway.Designing the future"Enabling the accelerators of the future depends on developing magnets with much greater field strengths than are now possible," says GianLuca Sabbi of Berkeley Lab's Accelerator and Fusion Research Division (AFRD). "To do that, we'll have to use different materials."Field strength is limited by the amount of current a magnet coil can carry, which in turn depends on physical properties of the superconducting material such as its critical temperature and critical field. Most superconducting magnets built to date are based on NbTi, which is a ductile alloy; the LHC dipoles are designed to operate at magnetic fields of about eight tesla, or 8 T - hundreds of thousands of times higher than Earth's magnetic field.The LHC Accelerator Research Program (LARP) is a collaboration among DOE laboratories that's an important part of U.S. participation in the LHC. Sabbi heads both the Magnet Systems component of LARP and Berkeley Lab's Superconducting Magnet Program. These programs are currently developing accelerator magnets built with niobium tin (Nb3Sn), a brittle material requiring special fabrication processes but able to generate about twice the field of niobium titanium. Yet the goal for magnets of the future is already set much higher."Among the most promising new materials for future magnets are some of the high-temperature superconductors," says Sabbi. "Unfortunately they're very difficult to work with." One of the most promising of all is the high-temperature superconductor Bi-2212 (bismuth strontium calcium copper oxide).In the process called "wind and react," Bi-2212 wire - shown in cross section, upper right, with the powdered superconductor in a matrix of silver - is woven into flat cables, the cables are wrapped into coils, and the coils are gradually heated in a special oven (bottom)."High temperature" is a relative term. It commonly refers to materials that become superconducting above the boiling point of liquid nitrogen, a toasty 77 kelvin (77 K, or -321 degrees Fahrenheit). But in high-field magnets even high-temperature superconductors will be used at low temperatures. Bi-2212 shows why: although it becomes superconducting at 95 K, its ability to carry high currents and thus generate a high magnetic field increases as the temperature is lowered, typically down to 4.2 K, the boiling point of liquid helium at atmospheric pressure.In experimental situations Bi-2212 has generated fields of 25 T and could go much higher. But like many high-temperature superconductors Bi-2212 is not a metal alloy but a ceramic, virtually as brittle as a china plate.As part of the Very High Field Superconducting Magnet Collaboration, which brings together several national laboratories, universities, and industry partners, Berkeley Lab's program to develop new superconducting materials for high-field magnets recently gained support from the American Recovery and Reinvestment Act (ARRA).Under the direction of Daniel Dietderich and Arno Godeke, AFRD's Superconducting Magnet Program is investigating Bi-2212 and other candidate materials. One of the things that makes Bi-2212 promising is that it is now available in the form of round wires."The wires are essentially tubes filled with tiny particles of ground-up Bi-2212 in a silver matrix," Godeke explains. "While the individual particles are superconducting, the wires aren't - and can't be, until they've been heat treated so the individual particles melt and grow new textured crystals upon cooling - thus welding all of the material together in the right orientation."Orientation is important because Bi-2212 has a layered crystalline structure in which current flows only through two-dimensional planes of copper and oxygen atoms. Out of the plane, current can't penetrate the intervening layers of other atoms, so the copper-oxygen planes must line up if current is to move without resistance from one Bi-2212 particle to the next.In a coil fabrication process called "wind and react," the wires are first assembled into flat cables and the cables are wound into coils. The entire coil is then heated to 888 degrees Celsius (888 C) in a pure oxygen environment. During the "partial melt" stage of the reaction, the temperature of the coil has to be controlled to within a single degree. It's held at 888 C for one hour and then slowly cooled.Silver is the only practical matrix material that allows the wires to "breathe" oxygen during the reaction and align their Bi-2212 grains. Unfortunately 888 C is near the melting point of silver, and during the process the silver may become too soft to resist high stress, which will come from the high magnetic fields themselves: the tremendous forces they generate will do their best to blow the coils apart. So far, attempts to process coils have often resulted in damage to the wires, with resultant Bi-2212 current leakage, local hot spots, and other problems."The goal of the program to develop Bi-2212 for high-field magnets is to improve the entire suite of wire, cable, coil making, and magnet construction technologies," says Dietderich. "The magnet technologies are getting close, but the wires are still a challenge. For example, we need to improve current density by a factor of three or four."Once the processing steps have been optimized, the results will have to be tested under the most extreme conditions. "Instead of trying to predict coil performance from testing a few strands of wire and extrapolating the results, we need to test the whole cable at operating field strengths," Dietderich says. "To do this we employ subscale technology: what we can learn from testing a one-third scale structure is reliable at full scale as well."Testing the resultsEnter the second part of ARRA's support for future magnets, directed at the Large Dipole Testing Facility.The LD1 test magnet design in cross section. The 100 by 150 millimeter rectangular aperture, center, is enclosed by the coils, then by iron pressure pads, and then by the iron yoke segments. The outer diameter of the magnet is 1.36 meters."The key element is a test magnet with a large bore, 100 millimeters high by 150 millimeters wide - enough to insert pieces of cable and even miniature coils, so that we can test wires and components without having to build an entire magnet every time," says AFRD's Paolo Ferracin, who heads the design of the Large Dipole test magnet.Called LD1, the test magnet will be based on niobium-tin technology and will exert a field of up to 15 T across the height of the aperture. Inside the aperture, two cable samples will be arranged back to back, running current in opposite directions to minimize the forces generated by interaction between the sample and the external field applied by LD1.The magnet itself will be about two meters long, mounted vertically in a cryostat underground. LD1's coils will be cooled to 4.5 K, but a separate cryostat in the bore will allow samples to be tested at temperatures of 10 to 20 K."There are two aspects to the design of LD1," says Ferracin. "The magnetic design deals with how to put the conductors around the aperture to get the field you want. Then you need a support structure to deal with the tremendous forces you create, which is a matter of mechanical design." LD1 will generate horizontal forces equivalent to the weight of 10 fully loaded 747s; imagine hanging them all from a two-meter beam and requiring that the beam not move more than a tenth of a millimeter.What's more, Ferracin says, since one of the most important aspects of cables and model coils is their behavior under stress, "we need to add mechanical pressure up to 200 megapascals" - 30,000 pounds per square inch. "We have developed clamping structures that can provide the required force, but devising a mechanism that can apply the pressure during a test will be another major challenge."The cable samples and miniature coils will incorporate built-in voltage taps, strain gauges, and thermocouples so their behavior can be checked under a range of conditions, including quenches - sudden losses of superconductivity and the resultant rapid heating, as dense electric currents are dumped into conventional conductors like aluminum or copper.At top, two superconducting coils enclose a beam pipe. Field strength is indicated by color, with greatest strength in deep red. To test components of such an arrangement, subscale coils (bottom) will be assessed, starting with only half a dozen cable winds generating a modest two or three tesla, increasing to hybrid assemblies capable of generating up to 10 T.The design of the LD1 is based on Berkeley Lab's prior success building high-field dipole magnets, which hold the world's record for high-energy physics uses. The new test facility will allow testing the advanced designs for conductors and magnets needed for future accelerators like the High-Energy LHC and the proposed Muon Collider."These magnets are being developed to make the highest-energy colliders possible," says Sabbi. "But as we have seen in the past, the new technology will benefit many other fields as well, from undulators for next-generation light sources to more compact medical devices. ARRA's support for LD1 is an investment in the nation's science and energy future."Additional informationMore on the Accelerator and Fusion Research Division's Superconducting Magnet ProgramMore about the the U.S. Department of Energy's LHC Accelerator Research Program (LARP)More about Berkeley Lab's world-record 16-tesla dipole magnetA symmetry breaking article on the Very High Field Superconducting Magnet CollaborationMore on American Recovery and Reinvestment Act support for the Large Dipole Facility
Orientation and navigationNavigation is based on a variety of senses. Many birds have been shown to use a sun compass. Using the sun for direction involves the need for making compensation based on the time. Navigation has also been shown to be based on a combination of other abilities including the ability to detect magnetic fields (magnetoception), use visual landmarks as well as olfactory cues.Long distance migrants are believed to disperse as young birds and form attachments to potential breeding sites and to favourite wintering sites. Once the site attachment is made they show high site-fidelity, visiting the same wintering sites year after year.The ability of birds to navigate during migrations cannot be fully explained by endogenous programming, even with the help of responses to environmental cues. The ability to successfully perform long-distance migrations can probably only be fully explained with an accounting for the cognitive ability of the birds to recognize habitats and form mental maps. Satellite tracking of day migrating raptors such as Ospreys and Honey Buzzards has shown that older individuals are better at making corrections for wind drift.As the circannual patterns indicate, there is a strong genetic component to migration in terms of timing and route, but this may be modified by environmental influences. An interesting example where a change of migration route has occurred because of such a geographical barrier is the trend for some Blackcaps in central Europe to migrate west and winter in Britain rather than cross the Alps.Migratory birds may use two electromagnetic tools to find their destinations: one that is entirely innate and another that relies on experience. A young bird on its first migration flies in the correct direction according to the Earth's magnetic field, but does not know how far the journey will be. It does this through a radical pair mechanism whereby chemical reactions in special photo pigments sensitive to long wavelengths are affected by the field. Note that although this only works during daylight hours, it does not use the position of the sun in any way. At this stage the bird is similar to a boy scout with a compass but no map, until it grows accustomed to the journey and can put its other facilities to use. With experience they learn various landmarks and this "mapping" is done by magnetites in the trigeminal system, which tell the bird how strong the field is. Because birds migrate between northern and southern regions, the magnetic field strengths at different latitudes let it interpret the radical pair mechanism more accurately and let it know when it has reached its destination. More recent research has found a neural connection between the eye and "Cluster N", the part of the forebrain that is active during migrational orientation, suggesting that birds may actually be able to see the magnetic field of the earth.VagrancyMigrating birds can lose their way and occur outside their normal ranges. These can be due to flying past their destinations as in the "spring overshoot" in which birds returning to their breeding areas overshoot and end up further north than intended. A mechanism which can lead to great rarities turning up as vagrants thousands of kilometers out of range is reverse migration, where the genetic programming of young birds fails to work properly. Certain areas, because of their location, have become famous as watch points for migrating birds. Examples are the Point Pelee National Park in Canada, and Spurn in England. Drift migration of birds blown off course by the wind can result in "falls" of large numbers of migrants at coastal sites.
When the models are not shown a person will not be able to know if there are any hydrogen atoms between them. If the models are shown a person will be able to know the answer.
By sprinkling iron fillings around a magnet the magnetic field can be shown. If the magnet is the opposite charge then the iron they will be repelled by the magnet showing how far the magnetic field reaches.
The magnetic field can easily be detected with a permanent magnet that is free to move - for example a compass (which has a magnetic needle), or a magnet hanging on a string.
strength, the number of lines represents how strong the magnet is, this is also sometimes shown by the thickness of the lines.
Put the compass on the table and, with the wire near the compass, connect the wire between the positive and negative ends of the battery for a few seconds. What you will notice is that the compass needle swings. Initially, the compass will be pointing toward the Earth's north pole (whatever direction that is for you), as shown in the figure on the right. When you connect the wire to the battery, the compass needle swings because the needle is itself a small magnet with a north and south end. Being small, it is sensitive to small magnetic fields. Therefore, the compass is affected by the magnetic field created in the wire by the flow of electrons.
Magnets are created by magnetizing certain metals that can be magnetized, called ferromagnetic materials. Ferromagnetic materials can be magnetized in the following ways: # Heating the object above its Curie temperature, allowing it to cool in a magnetic field and hammering it as it cools. This is the most effective method, and is similar to the industrial processes used to create permanent magnets. # 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 and which are subject to vibration (e.g. frame of a conveyor) have been shown to acquire significant residual magnetism. A magnetic field much stronger than the earth's can be generated inside a solenoid by passing direct current through it. # Stroking - An existing magnet is moved from one end of the item to the other repeatedly in the same direction.
Besides seeing what effect a strong magnet has on different metals, ... heavy mineral found in the displays, shown at the left in the first photo. .... Take a strong rare-earth magnet and place it into an inside-out zip-lock bag. ... Do you now have a fairly extensive list of things magnets can and cannot attract?
Yes, te fielc has flipped as shown by magnetic fields frozen in pottery from historical times.
Scientists have found evidence of Earth's magnetic field reversals by studying the alignment of magnetic minerals in rocks. These minerals record the direction and strength of the magnetic field at the time the rocks formed, providing a historical record of past field reversals. Additionally, paleomagnetic studies of seafloor spreading have shown alternating patterns of magnetic polarity along mid-ocean ridges, supporting the theory of magnetic field reversals.
Cut one in half, and see if the two bits attract or repel one another. If they do, you have cut the magnet. Otherwise the rod. If you are allowed other equipment, you don't need to cut anything. Make a coil, connect to a meter, and see which rod, when pushed in and out of the coil, induces a current.
Yes, the Earth's magnetic field has periodically reversed its direction throughout history. These reversals are known as geomagnetic reversals and have occurred many times over the past few million years.
Studies of pottery made in the past 5000 years have helped reveal fluctuations in Earth's magnetic field over the past 300 years. The iron minerals in the pottery align with the Earth's magnetic field at the time of firing, providing a historical record of magnetic field strength and direction. This data has contributed to our understanding of how the Earth's magnetic field has changed over time.
Electromagnetic waves are typically represented by sinusoidal waves in diagrams, where the oscillation of the electric and magnetic fields is shown propagating through space. The electric field is often shown as oscillating along one axis, while the magnetic field oscillates perpendicular to it. These representations illustrate the wave nature of electromagnetic radiation.