Applied Science - Built Environment (4) Post Lab
 OBJECTIVES: Exploring the uses of electromagnets. Comparing a generator and motor. VOCABULARY: electromagnet generator motor MATERIALS:   worksheet Students use a worksheet to find electromagnets in our lives.
 BACKGROUND: The electric generator and electric motor are similar because they both use current electricity and magnetism. The electric motor is essentially an electromagnet that is made to rotate within a stationary magnet. Electric motors provide power for all types of machinery, including home appliances. Gas motors also use electromagnets, but they require a generator to create electrical sparks for the gas to run the motor. In a car motor, the electrical energy can be supplied by the generator. A generator converts one form of energy into another Magnetic fields are the basis for electric bells, telephone receivers, radio and television speakers, tape recorders, and many other items. Electromagnets help control the intensity of signals as well as being a method of transmittal. Modern telephone systems rely on electromagnets. The telephone receiver is basically an electromagnet with a U_shaped yoke having coils wound on each leg of the U. Passage of the electrical signal through the coils causes magnetic attraction of a soft_iron diaphragm supported a small distance from the ends of the U. The diaphragm generates sound waves as it moves back and forth. Improvement in magnetic materials has increased the sensitivity of the telephone receiver, but the basic design has remained unchanged. The electromagnet has also played a primary role in research and is an indispensable tool in the quest to understand the universe by the use of electromagnetic waves. PROCEDURE: Use the enclosed sheet to have students find the electromagnet in the appliance.    Answers:  1. In a hand saw you can find an electromagnet in the motor.  2. In a toaster the electromagnet helps control the intensity of the coils.  3. The electromagnetic is found in the motor on this clothes dryer.  4. The electromagnetic is found in the speaker system and receiver system on a television.  5. There are no electromagnets in a coffee maker.  6. The receiver and speaker have electromagnets.  7. There are no electromagnets in a lamp.  8. The electromagnet is in the motor.  9. In an electric screwdriver, the motor contains the electromagnet . 10. The motor of a car has an electromagnet. The radio or cellular phone would have an electromagnetic.
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