Wired World

Benjamin Franklin could have died from many of his electricity experiments. One year he wanted to use electricity to kill a turkey for Christmas dinner. While checking his equipment, he touched two parts at the same time and got a big shock. His whole body vibrated, and his arms were numb until the next morning. He was lucky he wasn’t burned or electrocuted! 7 6 Ben Franklin Was Lucky! (Amps = watts ÷volts) Device Watts Watts ÷Volts Amps ceiling lamp 150 150 ÷ 120 1.25 table lamp 100 __________ __________ vacuum cleaner 900 __________ __________ color television 170 __________ __________ answering machine 6 __________ __________ space heater 1200 __________ __________ ceiling fan 20 __________ __________ computer 7 __________ __________ If everything were on at once, how many amps would you need? If you turn on the portable space heater, can you leave on all the lights? What can’t you use in the room when you’re vacuuming? TEAMWORK Here’s how watts, volts, and amps make a difference in a circuit. Let’s say the circuit breaker for the living room has tripped, cutting off the electricity. The living room circuit can carry 15 amps. The living room is served by 120-volt household electricity. Use the wattage and voltage for the following appliances to find out why the living room circuit is overloaded. Current Affairs Watts, volts, and amps measure electricity. To understand how they are related, think of water in a hose. You would use water that comes out really hard to wash off a muddy car. You would use water that comes out more slowly to water a garden. Turning on the faucet supplies the force, which is like the voltage. The amount of water moving through the hose is like the amperage. And you need different combinations of volts and amps to do different kinds of jobs. The work that electricity does in a job is measured in watts. 1 watt = 1 amp x 1 volt or 1 amp = 1 watt ÷ 1 volt 1. Your prediction:_ ________________________________________________________________ 2. What happened?_________________________________________________________________ 3. You built a short circuit. Explain why it’s called a short circuit. _________________________________________________________________________________ _________________________________________________________________________________ TEAMWORK Can you figure out why Ben Franklin got shocked? Discuss what will happen to the light when you set up the circuit below. Record your prediction. Set up the circuit and then lay the thick wire between the two exposed wires. Observe what happens. Then IMMEDIATELY remove the thick wire and disconnect the battery. SAFETY BASICS Touching as little as 60 milliamps (.06 amp) of electricity is probably fatal, and even 10 mil- liamps (.01 amp) could be fatal. That’s why you should never play with a wall socket or hit the electric lines that feed your house. SAFETY BASICS An electric circuit is designed to be safe. A short circuit takes electricity outside the safe path and can shock or kill people or start fires.