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Electricity and Magnetism Magic of Electrons © 2011 Project Lead The Way, Inc. Electricity and Magnetism • • • • • • • • What is a Magnet? North and South Poles of a Magnet Types of Magnets The Earth as a Magnet Electromagnets Electromagnetic Induction Motors Generators What is a Magnet? An object that is surrounded by a magnetic field and has the property of attracting iron or steel Where are Magnets? Magnets. . . Generate electricity Image courtesy of DOE/NREL Are in motors Image courtesy of DOE/NREL Where are Magnets? Magnets. . . Power car windows & locks Are used in Magnetic Resonance Imaging (MRI) Image courtesy of NASA North and South Poles of a Magnet Magnets have a north and south pole. • If a magnet is broken into smaller pieces, each piece will still have a north and south pole. • Opposite poles attract, like poles repel. N N S N N S S S S N Types of Magnets Magnets in Nature Magnetite is a mineral that is naturally magnetic. Human-Made Magnets Some materials can be magnetized when placed near a strong magnetic field. Soft magnetic materials (Iron) Hard magnetic materials (Cobalt, Nickel) Electromagnets Magnets can be made by passing a current through a coil of wire. U.S. Geological Survey / photo by Andrew Silver The Earth as a Magnet The Earth is a large magnet. Compasses work as a result of the Earth’s magnetic field. Electromagnets Magnets are created by passing a current through a wire. Electromagnets are generally wire wrapped around an iron core. Electromagnets are turned on and off when the current is switched on and off. Image Resources Microsoft, Inc. (2008). Clip Art. Retrieved October 20, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx U.S. Geological Survey Photographic Library (USGS). (2006). Retrieved October 20, 2008, from http://libraryphoto.cr.usgs.gov/index.html National Renewable Energy Laboratory (2008). Photographic information eXchange. Retrieved October 21, 2008, from http://www.nrel.gov/data/pix/searchpix.html