Electricity and Magnets

Electricity and Magnets Topic 4 – Physical Science Pages 328-337 Television and stereo speakers couldn’t work without magnets. Electricity and Magnetism How Are a Compass and a Magnet Alike? Attract and Repel Why Do a Hanging Magnet and Compass Turn? Earth itself is a magnet. Like a huge bar magnet running along Earth’s center, this magnet would create a region of magnetic force called a MAGNETIC FIELD. Lines of Force Where Do Magnets Come From? About 2,000 years ago, people from an area called Magnesia found rocks that would attract small pieces of iron. The rocks are called MAGNETITE. They contain magnetized iron. When the particles are all lined up in the same direction, their magnetic fields act together. Magnets can also be created using electric current. When an electric current flows a magnetic field forms around the wire. You can make a stronger magnetic field by winding a wire in loops around an iron bar. When electric current flows this creates a temporary magnet called an ELECTROMAGNET. Electromagnets How Are Electromagnets Used? A junkyard crane uses a powerful electromagnet. Doctors use electromagnets to take iron splinters out of patient’s skin. Recyclers use them to separate scrap metals. Electromagnets are also used in machines such as tape players, bells, motors, buzzers, loudspeakers, and televisions. How Does a Doorbell Work? An electric doorbell is made up of an electromagnet and a power source. How Can You Put Electricity to Work? Electric motors transform electrical energy into movement, or MECHANICAL ENERGY. This energy can power video recorders, some appliances, and other devices. Build Your Own Motor The following website offers directions for building your own motor! http://fly.hiwaay.net/~palmer/motor.html Additional Webquest The following webquest link is a great opportunity to further your learning! http://share1.esd105.wednet.edu/blackl /webquest.htm