Electricity and Magnetism Electricity and Magnetism What is

Electricity and Magnetism

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 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. N attract, like poles repel. N N N S S S N S S

Types of 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. le o th P r No le o th P u So 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 e. Xchange. Retrieved October 21, 2008, from http: //www. nrel. gov/data/pix/searchpix. html