What Do I Need to Know About a Bar Magnet?
Bar magnets are rectangular-shaped magnets with magnetic poles on both ends. Commonly made of Neodymium, samarium cobalt, ceramics or alnico (an alloy composed of aluminum, nickel and cobalt), bar magnets typically exhibit two magnetic poles which radiate towards each other for maximum magnetic force.
A Bar magnet have numerous applications in science and technology. From schools and colleges for magnetic experiments demonstration, to industries employing them in various forms such as cylindrical, rectangular horseshoe or ring magnets - bar magnets have an array of uses across fields of science.
If you are in the market for a bar magnet, it is crucial that you understand its characteristics before purchasing one. They come in various shapes and sizes but all share similar basic properties; two polarities (north and south) at both ends provide stronger magnetic forces than in between which is what makes these magnetic objects so useful.
Bar magnets feature permanent magnetic attraction that does not wear out even under high amounts of force, unlike electromagnets which require electrical current for operation. There are various methods to test the strength of bar magnets; one such method involves placing one near a piece of metal or material that will both attract and repel it, so that its magnetic attraction/repulsion forces can be easily seen when moving the magnet towards or away from this piece of metal.
Or you could use a compass to trace the magnetic field lines of a magnet. Since its needle acts like a magnet itself, it will follow along the magnetic field lines of a bar magnet exactly. Since magnetic poles attract each other strongly, the North indicator will point toward its south pole while Earth's south pole points toward its north.
How a magnet interacts with iron shavings and other similar materials is another method for evaluating its magnetic strength. You can do this by placing a bar magnet under a piece of paper and scattering metal shavings over it; under adult supervision, place your compass over this paper and watch as its needle points towards one or more magnetic poles of the magnet; magnetic field lines start from its North pole and move toward its South pole - these lines define its magnetic strength.
When two bar magnets come close together, their like poles will attract each other while unlike poles will repel each other. When taken further down to an atomic level, all magnets contain two opposite poles, and most often possess circular shapes.