Applied Science - Built Environment (4) Lab
 OBJECTIVES: Discovering methods of communications. Exploring how society communicates. VOCABULARY: circuit communication Morse Code telegraph MATERIALS: alligator clips lamp holder battery pack and batteries bulb metal tacks or push pins or switches paper clips piece of cardboard Students communicate using the Morse code.
 BACKGROUND: Communication was made possible by a telegraph. Sending information through a wire was big step forward in developing our current communication system. Although the telegraph, as represented in this lab, is not used as much as it was, its other uses such as the transmission of documents (FAX machines) have invaded the business market. The principle of the telegraph is still used, students just don't realize the impact to our society PROCEDURE: Emphasize that electromagnets are very important, as discussed in previous activities. This lab gives students hands-on experience with an electromagnet and knowledge about how it works.    First, draw the following diagram on the board to refresh student's memory of an electromagnet.    Use the model of the telegraph to demonstrate how it works, especially if this material was omitted in the PRE LAB. Go over how a telegraph was built and try to communicate with students using the Morse code. Use simple words.    Following directions on the lab sheet, students will make a switch using tacks, a paper clip, and cardboard. They should then use the alligator clips, a bulb, a bulb holder, battery, and switch to make a set up as shown in the diagram. Press the bent metal switch down on the tack. Release it. When the switch is pressed, the circuit is complete and the light flashes on. When the switch is released, the circuit is broken; the switch will spring up and away from the screw and the light will go off.    Students can practice the Morse code using this "mini" light telegraph. Make sure students know that there is no electromagnet in this exercise. A real telegraph can transmit information much farther than the simple circuit light telegraph because of the electromagnet which pulses a "sounder."
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