Materials Included In Kit

Additional Materials Required

Prelab Preparation

1. Cut one 15-cm length of PVC-insulated wire for each group for the Introductory Activity. This piece may also be used in constructing the quiz board. Note: The wire is thin enough that it may be cut with sturdy scissors if wire cutters are not available.
2. Strip 1.5 cm of insulation from both ends of each wire piece. If wire strippers are not available, use scissors to carefully cut through the insulation without cutting the wire and pull the insulation off.

Safety Precautions

Use caution when handling the insulated wire as the ends may be sharp. A 1.5-V battery has a low current and is considered safe. Keep hands dry when handling electrical equipment. Do not touch bare wire in a circuit. Remind students to wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.

Lab Hints

• Enough materials are provided in this kit for 30 students working in pairs. Both parts of this laboratory activity can reasonably be completed in two 50-minute class periods. The prelaboratory assignment may be completed before coming to lab, and the final design solution may be presented for a fun competition the second day.
• It is recommended that the instructor use a meter stick to measure the total length of wire for each group. Students may then cut their wire into the desired lengths.
• Students may need to be shown how to strip the insulation from the wire without cutting through or breaking the wire. If needed, give each group two 15-cm lengths of wire and allow them to practice stripping the insulation.
• If enough wire strippers are not available, the insulation may be cut and stripped with scissors. Show students how to gently cut through the insulation as they rotate the wire until the insulation is cut through but not the wire. The separated section of insulation may be pulled off by hand. Alternately, the insulated section of wire may be gripped and pulled with one hand while the blades of the scissors push the cut piece of insulation off the end. Care must be taken to not close the scissors too much and cut the wire. How-to videos of this technique may be found online.
• Consider whether or not to allow students to share materials. For example, will two groups be able to purchase one manila folder and cut it in half, so each group only pays $2.50?

Teacher Tips

• This is a great activity to incorporate engineering design with an electricity unit.
• Ask students to create a quiz that relates to their current unit of study.
• The quiz boards may be stored and used again for review with other units.

Answers to Prelab Questions

Read through the Background and Safety Precautions sections.

1. Indicate whether the following is a conductor or an insulator.
   1. glass microscope slide insulator
   2. copper pot conductor
   3. aluminum foil conductor
   4. plastic cup insulator
   5. cotton string insulator
2. Examine Figure 1.
   {14003_PreLabAnswers_Figure_1}
   1. Explain why the lightbulb is not lit.

      The switch is open, creating an open circuit. The current will not flow.

   2. What type of material must the arm of the switch be composed of in order for the lightbulb to light when the switch is closed?

      The arm of the switch must be a conductor in order to complete the circuit so the current will flow.

3. Explain why the wire that will be used to make the quiz board is covered with PVC material, a type of plastic.

   The plastic is an insulator, which makes handling the wire safer when it is part of a circuit.

Sample Data

Order Form

Answers to Questions

Engineering Design and Procedure

1. Consider the challenge assigned to your group. Write the problem you are designing a solution for in your own words.

   The problem is to construct an electronic quiz board in which a complete circuit is created when the correct match is made between a “question” and an “answer.” A bulb will light when the circuit is complete.

2. Out of what type of material(s) must the probes be made?

   The part of the probe the participant holds must be made of an insulating material so the participant doesn’t touch bare wire. A portion at each end must be made of a conductive material.

3. List all the components of the quiz board. Which ones will be part of the circuit?

   Manila folder
   Paper with quiz items
   Paper clips*
   Connector cords with alligator clips*
   Battery in holder*
   Lightbulb in receptacle*
   Insulated wire*
   *Circuit component

4. During the quiz, what completes the circuit to make the bulb light? How will the other circuit components be arranged?

   The circuit becomes closed when the two probes touch the conductor next to a question and the conductor next to the corresponding answer. When that happens, a continuous pathway must exist from one battery terminal to the bulb, to one probe, to the question conductor, along a connecting wire behind the board to the answer conductor, to the second probe and then to the other terminal of the battery.

5. Decide what type of quiz you will create and the number of quiz items. How will you determine the total amount of insulated wire needed for your board?

   Answers will vary. Sample give below is a metric matching quiz. The length of each connection was measured, including a few extra centimeters for hooking the bare wire onto the paper clips. The total length needed was calculated.

6. Brainstorm possible solutions to the challenge with your group. On a separate sheet of paper, draw sketches to represent your possible designs.
7. Choose the solution you believe will achieve the goal for the design challenge and meets all the criteria and constraints.
8. Fill out the Order Form on the Build an Electronic Quiz Board Worksheet and present it to your instructor.
9. Obtain the materials and build the electronic quiz board according to your plan. Test and evaluate the board.
10. Attach a copy of your final design of the back of the board to the worksheet. Include the “questions” and “answers.”
    {14003_Answers_Figure_1}

Post-Lab Questions

1. In the Introductory Activity, why didn’t the lightbulb light when the alligator clip was connected to the insulated part of the wire?

   The bulb did not light because current cannot flow through an insulator; the circuit was open.

2. What was the most challenging part of designing the quiz board?

   Answers will vary. Some challenges may include making sure enough variety of insulated wire lengths were included so the quiz could be reconfigured in a different question and answer arrangement. Students needed to decide whether to order extra insulated wire, “just in case.” If the wire connections were to be inside the folder, then slots needed to be cut in the fold of the folder for the paper clips. However, some groups may have chosen to use the double folder thickness to make a sturdier board.

3. Evaluate your final design solution.
   1. How successful were you at staying under budget?

      Answers will vary. If students made careful measurements and did not waste wire, staying under the $300 budget should not have been difficult.

   2. What improvements would you make if given the time and additional materials to redesign the electronic quiz board?

      Answers will vary, but may include using sturdier materials, using two-prong paper fasteners instead of paper clips, attaching a plastic sleeve (page protector) so quizzes could be easily interchanged, using connector cords with alligator clips (if more than three were allowed) for the connections behind the board, etc.

Introduction

Your design team has been charged with making an electronic quiz board. When the correct answer is selected, a lightbulb will light up. The challenge is to make a reusable quiz board while staying within budget.

Concepts

• Open versus closed circuits
• Conductors versus insulators
• Engineering design

Background

A continuous flow of electric charges is called a current. In order for a current to flow, a complete circuit is needed. An electrical circuit has three components—a source of electrical energy (voltage) like a battery or generator, a conducting path like wires, and resistance (e.g., a lightbulb, motor or speaker). In each of these examples, the electric energy is converted to light, motion or sound, respectively. The path through which the electricity flows must be continuous, or closed. If a break occurs anywhere in the circuit, it is considered an open circuit, and the current no longer flows.

Some materials allow electric charges to flow through them freely. Such materials are good conductors of electricity. Very poor or nonconducting materials that prevent the flow of electric charges are called insulators. Most metals are good conductors and most nonmetallic solids are insulators.

Experiment Overview

The purpose of this activity is to design an electronic quiz board. First a simple circuit will be made with a battery, bulb and connecting wires. The effect of an insulator on the current flow will be tested. The results will guide the design and construction of the quiz board.

Materials

Prelab Questions

Read through the Background and Safety Precautions sections.

1. Indicate whether the following is a conductor or an insulator.
   1. glass microscope slide
   2. copper wire
   3. aluminum foil
   4. plastic cup
   5. cotton string
2. Examine Figure 1.
   1. Explain why the lightbulb is not lit.
   2. What type of material must the arm of the switch be composed of in order for the lightbulb to light when the switch is closed?
   {14003_PreLab_Figure_1}
3. Explain why the wire that will be used to make the quiz board is covered with PVC material, a type of plastic.

Safety Precautions

Use caution when handling the insulated wire as the ends may be sharp. A 1.5-V battery has a low current and is considered safe. Keep hands dry when handling electrical equipment. Do not touch bare wire in a circuit. Wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.

Procedure

Part A. Introductory Activity

1. Screw a lightbulb into the lamp receptacle.
2. Connect one alligator clip to the negative terminal of the battery.
3. Attach the other end of the connector cord to one of the screws on the lamp receptacle.
4. Connect a second alligator clip to the positive terminal of the battery.
5. Touch the free end of the second connector cord to the other screw on the lamp receptacle to close the circuit. Once the bulb lights, pull the alligator clip away from the screw to open the circuit. Note: To prolong the life of the battery and the bulb, open the circuit as soon as the bulb lights up.
6. Obtain a third connector cord and a 15-cm piece of insulated wire. Note: About 1.5 cm of bare wire should be exposed at each end of the insulated wire.
7. Attach the other end of the connector cord that is attached to the positive battery terminal to one bare end of the wire.
8. Attach one alligator clip of the third connector cord to the second screw on the lamp receptacle (see Figure 2).
   {14003_Procedure_Figure_2}
9. Touch the free alligator clip to the free end of the insulated wire. The bulb should light.
10. Connect the free alligator clip to an insulated section of the wire. Does the bulb light?

Part B. Design Challenge

The challenge is to design and construct an electronic quiz board that can be reused. The form of the quiz may be questions and answers, matching, vocabulary words and definitions or any other type of quiz where words, phrases or numbers along the left side can relate to “answers” that are in a different order along the right side. When the corresponding “question” and “answer” are selected with two conductive probes, a circuit is completed and a bulb lights up. The quiz board must be constructed according to the design criteria and constraints given on page 3.

Design Criteria and Constraints

• The maximum cost cannot exceed $300. See the Build an Electronic Quiz Board Worksheet for a list of materials to be used and the cost for each.
• No more than three connector cords with alligator clips may be used.
• The quiz should be visible on the front of the board.
• The number of items to be matched for the quiz need to be no less than five and no more than ten.
• The connections between the questions and answers should not be visible to the participant.
• A drawing of the final design for the back of the board with the “questions” and “answers” should be made prior to construction.
• The participant will have two insulated probes—one to touch the “question” and one to touch the “answer.”
• The Order Form must be completed and presented to your instructor before materials may be obtained. If additional materials are needed during construction, the Order Form must be updated and a revised cost calculated.
• The piece of insulated wire used in the Introductory Activity may be used at no charge.
• The quiz board should be able to be reconfigured with the same sections of wire for additional quizzes.

Engineering Design and Procedure
Form a working group with other students and discuss the following questions.

1. Consider the challenge assigned to your group. Write the problem you are designing a solution for in your own words.
2. Out of what type of material(s) must the probes be made?
3. List all the components of the quiz board. Which ones will be part of the circuit?
4. During the quiz, what completes the circuit to make the bulb light? How will the other circuit components be arranged?
5. Decide what type of quiz you will create and the number of quiz items. How will you determine the total amount of insulated wire needed for your board?
6. Brainstorm possible solutions to the challenge with your group. On a separate sheet of paper, draw sketches to represent your possible designs.
7. Choose the solution you believe will achieve the goal for the design challenge and meets all the criteria and constraints.
8. Fill out the Order Form on the Build an Electronic Quiz Board Worksheet and present it to your instructor.
9. Obtain the materials and build the electronic quiz board according to your plan. Test and evaluate the board.
10. Attach a copy of your final design of the back of the board to the worksheet. Include the “questions” and “answers.”

Student Worksheet PDF

14003_Student1.pdf