"It's a Wired World" gives students hands-on activities about electric circuits which teach the basic principles of electrical safety. This booklet is appropriate for upper elementary and middle school students. "It's A Wired World" is formatted for use in classrooms or informal settings by cooperative learning groups. However, the activities can easily be presented by the teacher, leader, or by one small student group as a demonstration. And all the activities can be done by students individually. The activities in this booklet are quite diverse. Some require special materials. A list of materials for each page is noted in the Teacher's Guide, and a complete list of materials is included on the Web site. Where relevant, the materials list includes Radio Shack part numbers. These numbers are included as a convenience, not as an endorsement of Radio Shack. Comparable materials are available from other sources, such as your local hardware store. Ideally, each group will have its own set of materials. However, quantities in the materials list are given for a single group or person. Simply multiply by the number of groups to find how much you will need for a full class. Below are objectives, background information, teaching strategies, and suggested assessments for all of the sections. There is a list of materials for each page of hands-on activities, and we have included a quiz at the end.   PAGES 2-3 Main Idea Page 2: Electricity is part of our everyday lives. There are safety hazards associated with the equipment that brings it to us. Page 3: Electricity travels in a closed path called a circuit. Objectives Students will: Identify locations of potential danger in the circuit that runs from power plant to home or school and back. Build a circuit. Compare and contrast the circuit they constuct with the path of electricity from the power plant to home or school. Materials Give each group: 1 D cell battery 1 flashlight bulb 1-1/2 feet of 22-gauge wire Groups may also need: Tape Paper clips What You Need to Know Electricity only travels in a closed loop called a circuit. When you turn on a light or appliance, you are closing a circuit. Electricity will leave a circuit to take the easiest path to the ground. Safety hazards occur anywhere a person could come into contact with electrical lines or equipment. As long as a person is touching the ground (or something in contact with the ground), electricity has the potential to travel through him or her, causing shock, burn, or even death. Getting It Across Have students read the information and follow the steps on the page. Page 2: Ask students to share the potential safety hazards they identify. Page 3: Ask students to share their successful and unsuccessful circuits. Did They Get It? Are students able to: Identify the circuit electricity travels from the power plant to the home and back? Identify the circuit electricity travels from the battery to the light bulb and back? Answers Pg. 2 Potential Safety Hazards: Outdoors: climbing transmission towers; contacting high voltage lines or overhead distribution lines in your neighborhood with kites or balloons; entering a substation (for example, to retrieve a ball or toy); playing on or around a pad mounted transformer; contacting the service drop to home or school with TV antennae, ladders, long poles, or if the lines come in underground, by digging; climbing trees near power lines. Indoors: using appliances near water in bathroom or kitchen; putting fingers or other objects in outlets or toasters; overloading outlets; running cords underneath carpet; unplugging an appliance by the cord instead of by the plug. Pg. 3 What requirements must be met in order for the bulb to light? Wire must connect solidly at each terminal of the battery and at two places on the bulb (usually on the tip and on the side). If the connection is broken, the circuit is not complete and the bulb cannot light.   PAGES 4-5 Main Idea Pg. 4: Students need to know the difference between conductors and insulators in order to understand when they are in danger of contacting electricity and when they are not. Pg. 5: Water is an excellent conductor of electricity and if a person touches water that is electrified, even if he or she does not touch the source of electricity, he or she will be shocked. Objectives Students will: 1. Formulate operational definitions of insulators and conductors. 2. Demonstrate that water is a conductor of electricity. Materials Give each group: 2 alligator clips Groups will also need: The circuits they made on page 3 A variety of things they think might conduct electricity, for example: paper clips, aluminum foil, toothpicks, dirt, plastic, can, rubber bands, glass, paper, drinking straw, etc. A glass pint or quart jar 2 nails One 3"x5" piece of cardboard or cardstock (so that nails don't touch each other) Salt Water What You Need To Know Even good insulators may conduct electricity when wet. Teams will need to add a lot of salt to their water in order for electric current to flow. The voltage of the battery is so low that additional particles must be added to make the water more conductive. It is the impurities in water that make it a good conductor. Pure water will not conduct electricity. However, pure water is only found in the laboratory. That's why there is so much emphasis on the conductivity of water. You may want to remind students that they are able to work with these batteries and wires because the voltage is minimal (1.5 V per D cell battery). Getting It Across Page 4 Have students bring in things they think might conduct electricity. Have teams read the information and follow the steps on the page. Students should first test their circuit by connecting it without any trial material in between. Ask teams to share their predictions and results. Were the results the same? If not, why not? (Be sure the experimental set up was not at fault.) What conclusions can students draw about conductors and insulators? (They might generalize that metals are good conductors or glass or plastic are good insulators.) Page 5 Be sure students add plenty of salt to the water. Then ask them to predict, experiment, and note their observations. Share results. Emphasize that salt is needed because the battery is weak. It's the low voltage that keeps them safe and allows them to experiment with electricity. Did They Get It? Are students able to: List materials that are conductors and insulators? Draw the path electricity traveled through their test circuits? State that water is an excellent conductor of electricity?   PAGES 6-7 Main Idea Circuits can carry a specific amount of electricity. That amount is measured in watts, volts, and amps. When there is some kind of "leak" in a circuit that allows the electricity out of its specified path, a short circuit results. The electricity will go to ground, and if you are in the way, like Ben Franklin was, it will travel through you. Objectives Students will: Practice converting from one unit of measure to another. Recognize that there are limits to the amount of current a circuit can carry. Demonstrate a short circuit and define it. Materials Give each group: 6" of thicker wire Groups will also need: The circuits they made on page 3 What You Need To Know Watts, volts, and amps are the units of measure of electricity. Students need to understand these units and their relationship in order to calculate whether a circuit can carry the load required of it. A short circuit is a circuit through which electricity is not able to complete its travel because the circuit is grounded somewhere. It is important to emphasize that even though Ben Franklin was not seriously hurt in the example, electricity is always dangerous. Electricity's unpredictability adds to its danger. Again, you may want to remind students that they're able to work with these batteries and wires because the voltage is minimal (1.5 V per D cell battery). Getting It Across Page 6 Help students read the opening narrative. They need to know that watts measure work, amps measure electric current, and volts measure the "pressure" of the current. You might help them remember the relationship by showing them that they can remember the formula W = VxA by remembering West Virginia: W. VA. The application at the bottom of the page shows them one of the main reasons to learn this formula--so they can tell what causes a circuit to become overloaded. Page 7 Have students read the information and follow the steps on the page. BE SURE STUDENTS UNDERSTAND THAT THEY SHOULD IMMEDIATELY DISCONNECT THE THICK WIRE AND THE BATTERY AFTER THEY OBSERVE WHAT HAPPENS. The wires will get hot. Did They Get It? Are students able to: Calculate the number of amps required by household appliances? Describe a short circuit and compare it to the story about Ben Franklin? Answers Page 6 Table lamp, 0.83 A; vacuum cleaner, 7.5 A; color TV, 1.42 A; answering machine, 0.05 A; space heater, 10 A; ceiling fan, 0.17 A; electric clock, 0.03 A. You would need 21.25 A. Yes. Yes. Run the space heater. Page 7 Because the electricity traveled a shorter route than the intended circuit. Ben Franklin functioned like the thick wire in the students' experiments. Electricity traveled through his body instead of through the circuit and he got shocked.   PAGES 8-9 Main Idea Electricity will always take the easiest route to the ground. It is this attribute of electricity that makes it dangerous to people, because we are almost always touching the ground or something in contact with the ground. Safety devices including 3-pronged plugs, Ground Fault Circuit Interrupters, fuses, and circuit breakers are built into circuits to help prevent dangerous situations. Objectives Students will: Identify potential danger of electric shock. Recognize that a person must be grounded to get shocked. Build a basic switch, explain how it works, and compare it with a circuit breaker and/or fuse. Materials Give each group: 1 bulb holder 1 brass fastener Several paper clips, large and small Groups will also need: The circuits they made on page 3 A piece of cardboard What You Need To Know Electricity always travels the easiest path to ground. Birds sitting on an electric line don't get shocked because they aren't touching anything that is touching the ground. The lines they sit on are insulated from the ground by glass or ceramic disks. The disks don't allow the lines to touch the poles which would be a route to the ground. However, if those birds take flight and their wings touch two lines at once, or if they touch a pole and wire at the same time, they will get shocked and could die. Switches are a convenient way to open and close a circuit. Circuit breakers and fuses are like automatic switches that open a circuit if it becomes overloaded. Getting It Across Have teams read the information and follow the steps on the page. Page 8: Use the example of the bird on the wire to be sure students understand that they are in danger because they are always grounded. You might suggest that they try to find ways not to be grounded and evaluate the ideas as a class. (Remember that rubber tennis shoes or rubber kitchen gloves cannot shield a person from electric current. Utility workers use special equipment to touch electrical equipment.) Page 9: If students cannot figure out how to construct a switch, here is a diagram. Did They Get It? Are students able to: Identify dangerous situations around electricity? Explain what grounding has to do with the danger of contacting electricity? Build a switch and explain how it works? Answers Pg. 8 Dangerous pictures are: upper left and lower left. Pg. 9 Sample explanation: When the switch is turned on, the contact points of the brass fastener or the paper clip connect to the wires and complete or close the circuit. The bulb lights. When the switch is turned off, the arms break the connection, and the circuit is open. The bulb goes out.   PAGES 10 - 11 Main Idea Students wire a simple distribution system which demonstrates again that the path electricity travels from the power plant to homes and back is a circuit just like the one they built. The model distribution system also allows students to understand the function and dangers of substations. Objectives Students will: Design and build an electric circuit for a model shoebox cabin. Wire the cabins together to learn the function of distribution lines, substations, and how neighborhoods are linked to power plants. Trace the path of electricity from its source at the power plant to the substation to the cabins and back again. Be able to identify potential dangers of substations. Materials Give each group: 4 feet of wire (page 8) 1.5 feet of wire (page 9) One or two colors of yarn Groups will also need: The bulbs, bulb holders, and batteries from their circuits 1 shoebox or other small box Art supplies such as scissors, tape, glue, pencils, crayons, rulers, drawing paper, construction paper What You Need To Know The bulb holders will be very useful in this activity, if students have not already used them. The shoebox cabin village works best if no more than 4 cabins are hooked together. Hook up the D cell batteries in a series (like a flashlight) to power the network. Substations are a crucial link in the electricity distribution network. Electricity from many different power plants comes into a substation. The voltage level is stepped down, and the electricity is distributed from the substation to homes, schools, and businesses. Be sure students understand that substations don't generate electricity, even though in the shoebox cabin network, the batteries are located in the substations. Electricity is generated at the power plants. Getting It Across Have teams read the information and follow the steps on the page. Have teams show each other the path that electricity follows in each cabin. When the shoebox cabin network is complete, ask students to trace the path of electricity from the power plant, through the cabins, and back again. Did They Get It? Are students able to: Successfully draw the electric circuit for the cabin and transfer the drawing to the model? Wire the cabins together into a network? Identify the hazards of substations and make appropriate signs to warn people away? Identify the power plant as the source of electricity, and trace the circuit electricity travels from the power plant to the substation, to the cabins and back again?   PAGES 12 - 13 Main Idea Appropriate behavior in electrical emergencies is "counter-intuitive." Instead of rushing in to help, everyone must be certain that the source of electricity is no longer live. Otherwise, the would-be rescuer will also be shocked. Objectives Students will: Practice research and interview skills. Analyze information to find the cause of an electrical accident. Identify bodily effects of contact with electricity. Apply their knowledge of circuits to explain how to prevent electrical accidents and how to behave in situations involving downed power lines. Recognize that in an electrical emergency, the best help may be to stay away. Identify 3 steps to take in an electrical emergency. What You Need To Know Page 13: This teaches students that other people may not be able to help someone trapped in a car with a power line on it. The best help onlookers can give is to call 911 or the local emergency number. Students may think that if a person is already shocked or burned, the danger is over. But if the source of electricity is still live and near or touching the victim, the situation could be deadly for someone who approaches too closely. Getting It Across Page 12: Have teams read the information and research their topics. As teams share their stories with the class, ask the class to identify how the accident happened, how electricity affected the body (if possible), and how the accident could have been prevented. Page 13: Have students read the information on the page. Ask them why they should stay away from someone who has been shocked or burned? (Because the helper could become part of electricity's path and also get hurt.) Ask students to name the steps to take in event of an electrical emergency. (1: Stay away from the person who is hurt. 2: Tell an adult to pull the plug from the outlet or turn off the power at the circuit box. 3: Call for help.) Ask students why no one should use water to put out an electrical fire. (Because water conducts electricity. The person dousing the flames could be shocked as electricity traveled through the stream of water or water could spread out in a pool from the victim and the source of electricity and hurt anyone standing in that water.) Did They Get It? Are students able to: Name the causes of electrical accidents in the examples they find? List several safety rules that could have prevented these accidents? Demonstrate how to leave a car with a power line on it? Describe the dangers to the rescuer in an electrical emergency and list appropriate steps to take? Tell why water isn't used to put out electrical fires?   PAGES 14 - 15 Main Idea Letting your students teach children about electrical safety is one of the best ways to reinforce student learning. Objectives Students will: Develop questions to survey younger students. Draw conclusions about what students know from the answers to their questions. Correct any misconceptions younger students may have about electrical safety. What You Need To Know Ask your students to organize their knowledge and share it with younger students. You may need to make arrangements for your students to work with another class. Surveys will reveal younger students' misconceptions or lack of knowledge. Your class skits could be used as one way to teach younger students how to stay safe around electricity. Page 15: Students may use suggested scenes or develop their own skits. Getting It Across Have students read the information on the page and follow the directions on page 14. Have students use the information they gather as the basis for the skits they develop. Ask teams to talk with younger students after the performance to find out what they learned from the skits. Did They Get It? Are students able to: Draw accurate conclusions about what younger students do and don't know about electrical safety? Create a skit to teach younger students basic safety rules?   SUMMARY QUIZ Fill in the blanks. Electricity travels in a closed path called a __________________. In the bulb and battery circuit, the electricity came from the____________________. In the circuit that serves your home, the electricity comes from the ____________________. Name 3 conductors: __________________ _____________ _________________ Name 3 insulators: __________________ _____________ _________________ Electric current is measured in _____________. The "pressure" behind it is measured in volts. The work electricity is measured in ______________. Write or draw your answer in the space provided. Describe two dangerous situations around electricity outdoors. Describe two dangerous situations around electricity indoors. Draw your battery and bulb circuit and show the path that electricity travels in this circuit. Describe or draw the path electricity would take if a person contacted electricity because the insulation of the cord of their electric lawn mower was cracked and the grass was wet. ANSWERS TO QUIZ Circuit Battery Power plant or generating plant Answers will vary. Examples: wire, paper clip, water, nails Answers will vary. Examples: plastic, glass, wood, dirt, rubber Amps, watts Answers will vary. Examples: climbing transmission towers; contacting high voltage lines or overhead distribution lines in your neighborhood with kites or balloons; entering a substation (for example, to retrieve a ball or toy); playing on or around a pad-mounted transformer; contacting the service drop to home or school with TV antennae, ladders, long poles, or if the lines come in underground, by digging; climbing trees near power lines. Answers will vary. Examples: using appliances near water in bathroom or kitchen; putting fingers or other objects in outlets or toasters; overloading outlets; running cords underneath carpet; unplugging an appliance by the cord instead of by the plug. Students should show bulb with wires connected to tip and side of metal housing at the bottom, and the battery with wires connected to each end. Electricity travels from the battery through the wire to the bulb, across the filament, through the other wire back to the battery. Electricity would travel from the power cord of the lawn mower through the water in the grass, and up through the person's legs. Depending on the position of the person at the time of contact, electricity could simply travel up one leg and down the other. Or, it could travel up one leg, through the heart, and out a hand that was touching the mower handles.