STC Second Edition Electric Circuits Unit In-Service Training Outline Carolina Biological Supply Company 2700 York Road Burlington NC 27215 800.334.5551 www.carolina.com 0508
Electric Circuits (using the Second Edition Teacher s Guide) NOTE: Unless otherwise specified, all page numbers provided in this outline refer to Section 4, Unit Investigations and Blackline Masters, in the Second Edition Teacher s Guide. Recommended Length for Full Workshop: 4 hrs. Site Requirements: overhead projector, blank overhead transparencies, transparency markers, flat-topped work tables, one 6-ft. or longer table for materials setup Recommended Work Groups: individuals (lessons 1-3, 5, 12, 17); teams of 2 (lessons 7-11) Recommended Activity Sheet: 1 (p. 19) Recommended Overheads: Activity Sheet 1 (p. 19), Fig. 4-1 (p. 22), Fig. 5-3 (p. 28), Fig. 6-1 (p. 34), A Secret Language (p. 57), Fig. 11-3 and 11-4 (p. 61), Fig. 12-1 (p. 66) Pre-workshop Preparation: construct a hidden circuits box, or plan to do this as part of your On-site Preparation On-site Preparation: place a meterstick, yardstick, tape, etc., on a table as a guide for cutting wire. Cut an 8" (20-cm) piece of wire for each participant and strip both ends. Set out a wire, battery, and bulb (microlamp) for each participant. Set out the battery holders and bulb sockets for easy pickup. 2005 Carolina Biological Supply Company. The STC unit Electric Circuits was researched and developed by the National Science Resources Center, Washington, DC, and is available exclusively from Carolina Biological Supply Company. This document may be reproduced only by educators in schools and districts in which the Electric Circuits unit will be taught.
Electric Circuits Workshop Introduction to the unit: 1. Electric Circuits is a 17-lesson unit for fourth graders (it can also be used with third and fifth graders). In lessons 1-6, students learn about electric circuits and the parts of a light bulb. In lessons 7-10, students learn about conductors, insulators, and electrical symbols. In lessons 11-16, students explore different kinds of circuits, learn to use an electrical switch, and wire a cardboard box house. In lesson 17, students return to their work from lesson 1 to review what they ve learned about electricity. 2. Explain the use of icons for curriculum integration. 3. Briefly go over Teaching Strategies (Section 2, Unit Overview, p. 10-11). Also review Assessing Students Progress (Section 2, Unit Overview, p. 12) and Student Assessment (Section 5). 4. Briefly explain Materials Management and Safety (Section 3), and Student Notebooks and Writing, Student Reading Resources, and Additional Learning Resources (Sections 6 through 8). The lessons Lesson 1 Thinking about Electricity and Its Properties Explain the purposes of brainstorming. Then write on an overhead, What we know about electricity. Ask the teachers to give what they think will be student responses. Lesson 2 What Electricity Can Do 1. Direct attention to the wire, battery, and bulb. Instruct them to use these materials to light the bulb. 2. Observe their efforts and gauge skills/knowledge levels. Lesson 3 A Closer Look at Circuits Have them fill in Activity Sheet 1. They can try any combinations they are uncertain of. Show the activity sheet as an overhead and go over the answers. Emphasize the progression toward the concept of a complete circuit. 2
Lesson 4 What Is Inside a Lightbulb? 1. Demonstrate how to remove the base from a bulb. Go over the parts of a bulb, using Fig. 4-1 as an overhead. 2. Use batteries to light the household bulb as directed on p. 23. Lesson 5 Building a Circuit 1. Demonstrate the use of the battery holder and bulb socket. As part of the explanation, use Fig. 5-2 as an overhead to introduce the use of the Fahnestock clip. 2. Demonstrate the use of the wire stripper tool. Have each person cut two 8" pieces of wire and strip the ends. At the same time, they can pick up a battery holder and a bulb socket. 3. Each participant should now put the batteries and bulbs in their respective holders and connect them with wires to light the bulbs. Lesson 6 What s Wrong with the Circuit? Use the faulty bulb to demonstrate troubleshooting. Lesson 7 Conductors and Insulators 1. Give out the packages of assorted objects. (As there are 15 packages, they may have to work in teams of 2.) Ask them to divide the objects into insulators and conductors. 2. Show Fig. 6-1 as an overhead. Have the participants assemble the circuit testers and use them to check their predictions. Lesson 8 Making a Filament Either give each participant an extra battery and holder or let them work in pairs to complete this activity. 1. Explain that nichrome is an alloy of chromium and nickel that has a high resistance to the passage of electricity. Illustrate the energy conversion by the analogy of rubbing the palms of your hands together to produce heat: mechanical energy + friction heat energy and electrical energy + resistance heat energy Point out that as the element of an electric range heats up, it glows. Nichrome wire is used in the heating elements of many household appliances such as toasters and hair dryers. 3
2. Following the directions on p. 47, show how to build the device pictured in Fig. 8-1 (p. 46). (Do not spoil things by completing the electrical connections and making your filament glow.) Warn them to connect the nichrome wire before connecting the batteries; otherwise, they get burned. Go over the Safety Reminders on p. 46. 3. Let the teams cut nichrome wire and begin work. Remind participants to hold a thumb over the roll of nichrome wire so it will not spring off the roll. The most common problems are too much nichrome wire between the uprights, more than one strand of nichrome wire between the uprights, poor connection of nichrome wire to the uprights, and batteries pointing in opposite directions. 4. Once teams are successful, disconnect the batteries to avoid draining them. Lesson 9 Hidden Circuits Note: If time is short, this can be a demonstration only. 1. Show the hidden circuit box that you constructed earlier. Explain that some of the contact points are connected by wires that are hidden inside the box. Demonstrate how a contact point is made with a paper fastener, washer, and Fahnestock clip. Then show a circuit tester and remind them of its use. Ask, Without opening the box, how could we use this circuit tester to determine which of the contacts are connected? Wait for their responses, then ask them to come up with a logical plan to most easily and quickly identify the connected contact points. 2. Have each team pick up a box (flat), 8 Fahnestock clips, 8 paper fasteners, and 8 washers. They must share screwdrivers and rolls of masking tape. 3. Demonstrate how to fold a box. 4. Have the teams construct hidden circuit boxes. 5. Have the teams exchange boxes and identify the connected contact points. Lesson 10 Deciphering a Secret Language Show p. 57 as an overhead. Explain the symbols and why they are used (see Background p. 53). Using the symbols, diagram a circuit showing a battery connected to a bulb. Ask them to tell you what the diagram represents. Use a battery in a holder, etc., to construct the circuit. Point out the corresponding parts of the diagram and actual circuit. Lesson 11 Exploring Series and Parallel Circuits 1. Refer to Fig. 11-2, p. 34 of the Student Investigations book (formerly known as the Student Activity Book). Explain series and parallel. Spend some time comparing the illustrations to the circuit diagrams. 2. Have participants follow the instructions on p. 34 to build and explore the 2 kinds of circuit. 4
3. Show overhead of Fig. 11-3 and 11-4. Explain that in these circuits it is the bulbs that are in series and parallel. Have the teams construct these circuits and explore them. Lesson 12 Learning about Switches 1. Each person will need an index card, paper clip, 2 paper fasteners, 2 washers, and 2 Fahnestock clips. 2. Show the overhead of Fig. 12-2 and have them make the switch. Some groups will need to be led step-by-step through the process. Others will need no further instruction. 3. Have them hook up the circuit shown in Fig. 12-3 on p. 39 in the Student Investigations book, and demonstrate the use of a switch. Lesson 13 Constructing a Flashlight Students construct the circuit of a typical flashlight (2 batteries in series connected to a bulb through a switch). Teams should construct the circuit and then diagram it. If you need to save time, this lesson can be skipped or talked through. Lesson 14 Working with a Diode 1. Give each team a diode. Explain that the wires are electrical contacts and that the diode is the cylinder in the center. 2. Have the teams complete steps 1-3 on p. 44 of the Student Investigations book to explore the electrical nature of the diode. 3. Point out that the diode is a basic electronic device. Its invention led to radio, television, computers, microwave ovens, etc. Lesson 15 Lesson 16 Planning to Wire a House, and Wiring and Lighting the House In most cases you will do these lessons as a talk-through or show-and-tell. Students use all their knowledge and skills to wire a model house. Lesson 17 Post-Unit Assessment Teachers will review students responses from lesson 1 to determine how much they learned in the Electric Circuits unit. 5
Wrap-up 1. Give out any evaluation forms and ask that they be completed. 2. Ask for help in cleanup. 3. Be available for questions/discussion. 6