Materials Included In Kit

Additional Materials Required

Prelab Preparation

1. Cut one 18" length of aluminum wire for each group for the Introductory Activity. This piece may also be used in constructing the game. Note: The wire is soft enough that it may be cut with sturdy scissors if wire cutters are not available.
2. Check the buzzer wires to ensure there is sufficient length of bare wire for a good connection with the alligator clips. Strip additional insulation if necessary.

Safety Precautions

Use caution when handling the aluminum wire as the ends may be sharp. A 1.5-V battery has a low current and is considered safe. Remind students to wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.

Disposal

Materials may be stored for future use. Used aluminum wire may be thrown in the trash or check with local recycling centers.

Lab Hints

• Enough materials are provided in this kit for eight student groups. Both parts of this laboratory activity can reasonably be completed in two 50-minute class periods. The pre-laboratory assignment may be completed before coming to lab, and the final design solution may be presented for a fun competition the second day.
• The following materials are suggestions for testing in the Introductory Activity. In addition to the materials included, allow students to test 2 or 3 more.

  Conductors
  Aluminum foil
  Copper penny (copper-plated zinc)
  Iron nail
  Steel paper clip

  Insulators
  Cloth
  Glass microscope slide
  Paper
  Plastic spoon or cup

• The piezo buzzers included may operate on 1.5–12 volts. The higher the voltage, the greater the current and the louder the sound. One 1.5-V battery is recommended for a tolerable noise level during the introductory activity. Students may also cover the opening in the buzzer to muffle the sound during testing. A second battery may be required in order to hear the buzzer when contact is made between the wand and the wire in the wire maze game, depending on the design.
• Determine whether students may use additional materials from the classroom or home to make the game. The materials included in the kit are sufficient to make a successful design. The screw eye may be used as the loop, but some may find the ⅜" diameter too challenging. Students may make a loop out of additional aluminum wire wound around a cylindrical object that is ½-inch diameter or greater. They should determine the exact length of wire needed and measure and cut that length to avoid wasting wire.
• The foam base is an ideal support since the end of the wire maze may be easily inserted and it is an insulator. If desired, students may modify the size of the base or decorate it. A plastic knife will cut through the base fairly easily.

Teacher Tips

• This is a great activity to incorporate engineering design with an electricity unit.
• Challenge students to find a way to quantify the amount of time the loop is in contact with the wire maze. One student included a battery-operated analog clock with a second hand in the circuit so whenever the circuit was closed, the second hand moved.

Answers to Prelab Questions

1. Label each diagram below as a closed circuit or an open circuit. 
   {14004_PreLabAnswers_Figure_3}
2. Suppose an insulator was placed in the circuit between the battery and the lightbulb in Diagram A.
   1. Would the lightbulb light?

      The lightbulb would not light.

   2. Give a reason for your answer.

      Electrical charges cannot flow through an insulator.

3. On a camping trip, you take your flashlight out of your backpack, push the switch, but the light doesn’t come on.
   1. Describe at least three possible reasons why the flashlight doesn’t work.

      The filament in the bulb may be broken; the battery may be dead; a connecting wire may be broken or disconnected.

   2. How would each of the reasons described affect the flow of current in the flashlight?

      The broken filament and broken or disconnected wire would create an open circuit, stopping the current flow. If the battery was dead, the circuit would have no voltage. Without a source of electrical energy, the current won’t flow.

Sample Data

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 make a wire maze game to test hand steadiness that is both challenging and fun. A wand with a conductive loop at one end must encircle the wire. Touching the loop to the wire at any time as it is moved along must close the circuit so the buzzer sounds.

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

   The handle of the wand must be made of an insulating material so the participant can hold it without touching bare wire. The loop at the end must be made of a conductive material. The loop must also be connected to other conductive material so when it touches the wire, the circuit is closed.

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

   Battery*
   Buzzer*
   Connector cords*
   Electrical tape
   Insulated base
   Wand handle
   Wand loop*
   Wire maze*
   *Circuit component

4. During the game, what completes the circuit to make the buzzer sound? How will the other circuit components be arranged?

   The circuit becomes closed when the conductive loop touches the wire maze. When that happens, a continuous pathway must exist from the positive battery terminal to the buzzer, to the wand, to the wire maze, and then to the negative terminal of the battery.

5. What possible safety hazards may exist and what precautions will you take to avoid those hazards?

   The wand handle must be insulated so participants do not touch bare wires. The ends of the wires may be sharp. They could be covered with electrical tape as long as the tape doesn’t interfere with the complete circuit.

6. How will you ensure the game is challenging, yet not so difficult that participants give up too easily? How will the winner be determined?

   Answers will vary, but may involve the diameter of the loop and the number and types of turns in the maze. The winner may be determined by how many “buzzes” are heard from the beginning to the end or how far along the maze one gets before the first buzzer sound.

7. Brainstorm possible solutions to the challenge with your group. On a separate sheet of paper, draw sketches to represent your possible designs.
8. Choose the solution you believe will achieve the goal for the design challenge and that meets all the criteria and constraints.
9. Obtain the necessary materials and build the wire maze game according to your choice. Test and evaluate the game.
10. Attach a copy of your final sketch to the worksheet. Be sure to label parts of the game and show circuit connections.

    One possible design is shown below. (Not drawn to scale.)

    {14004_Answers_Figure_4}

1. Scientists ask questions about natural phenomena and conduct investigations to find the answer to the question. Engineers define problems related to human needs and wants and design the best solution among many possible outcomes
   1. In what part of this activity were you conducting a scientific investigation to answer a question?

      In the introductory activity, testing various materials to see if they were conductors or insulators was a scientific investigation.

   2. In what part of this activity were you defining a problem and designing a solution like engineers?

      Making a wire maze game required defining the specific problem and then designing the game to meet the given criteria and constraints.

2. Based on the results recorded in the data table, what property do the conductors have in common?

   All the conductors were made of metal.

3. A student read that the lead in his wood pencil is actually graphite and that graphite is a conductor. He decided to investigate and set up a circuit from a battery to a small light bulb and then to the graphite tip of the pencil. Since the eraser end of the pencil had a metal strip around it, he connected the metal strip to other terminal of the battery. The bulb did not light so he concluded that the graphite was not a conductor after all.
   1. Was the student correct in his conclusion?

      No, the conclusion was not correct.

   2. Give an explanation for your answer.

      The graphite in the pencil is surrounded by wood, which is an insulator, and is not connected to the metal strip around the eraser. The student did not make a complete circuit. Even if he had made a complete circuit and the lightbulb did not light, it may have been because the bulb was burned out or the battery was dead.

4. Evaluate your final design solution.
   1. How successful were you at making a wire maze game that was challenging yet fun?

      Answers will vary. If the winner is the person with the fewest “buzzes,” students may find it difficult to determine if several “touches” in the same spot on the maze should be considered as one or more than one, which would make determining the winner difficult.

   2. What improvements would you make if given the time to redesign the game?

      Answers will vary, but may include using sturdier materials, making a base that can hide the battery, wires and buzzer, finding a way to quantify the amount of time the loop touched the wire or the distance the loop moved along the wire before the first buzz, etc.

Introduction

Put your hand–eye coordination to the test! Learn about electric circuits, conductors and insulators and then apply your knowledge to make a fun wire maze game! Whose hand is steadiest?

Concepts

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

Background

A continuous flow of electric charges is called a current. In order for a current to flow and do work, 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.

Experiment Overview

The purpose of this activity is to make a wire maze game that depends on a steady hand for success! In the introductory activity, the conductivity of various materials will be investigated. The results will help guide the design of the game.

Materials

Prelab Questions

1. Label each diagram as a closed circuit or an open circuit.
   {14004_PreLab_Figure_2}
2. Suppose an insulator was placed in the circuit between the battery and the lightbulb in Diagram A.
   1. Would the lightbulb light?
   2. Give a reason for your answer.
3. On a camping trip, you take your flashlight out of your backpack, push the switch, but the light doesn’t come on.
   1. Describe at least three possible reasons why the flashlight doesn’t work.
   2. How would each of the reasons described affect the flow of current in the flashlight?

Safety Precautions

Use caution when handling the aluminum wire as the ends may be sharp. A 1.5-V battery has a low current and is considered safe. Wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.

Procedure

Part A. Introductory Activity

1. Connect one alligator clip to the positive terminal of one battery.
2. Attach the other end of the connector cord to the bare end of the red wire from the buzzer.
3. Attach a second alligator clip to the bare end of the black wire from the buzzer.
4. Touch the free end of the second connector cord to the negative terminal of the buzzer to close the circuit (see Figure 1). If the buzzer sounds, pull the alligator clip away from the negative terminal to open the circuit. Note: To prolong the life of the battery and avoid annoying everyone else in the room, do not let the buzzer sound for more than a second or two!
   {14004_Procedure_Figure_1}
5. If the buzzer does not sound, make sure all connections are secure and that the red wire of the buzzer is connected to the positive terminal of the battery. Repeat step 4.
6. Maintain the connections as in steps 1–3.
7. Attach the free alligator clip to one end of the wood tongue depressor.
8. Obtain a third connector cord and attach one alligator clip to the other end of the tongue depressor.
9. Touch the free end of the third connector cord to the negative terminal of the buzzer. Record whether or not the buzzer sounds and indicate if the material is a conductor or an insulator in the Data Table on the Make a Wire Maze Game Worksheet.
10. Repeat steps 6–9 three more times and replace the tongue depressor with the screw eye, the aluminum wire and a piece of electrical tape, respectively.
11. Test whether or not the foam base is an insulator or conductor. Since the alligator clips cannot be attached to the foam, attach a connecting cord between the positive battery terminal and the red wire of the buzzer and one end of a second wire to the negative battery terminal. Insert the bare end of the black buzzer wire into one end of the foam and then touch the free alligator clip to the other end of the foam. Record the results in the data table.
12. Test two or three other objects supplied by your instructor as in steps 6–9. Record the results in the data table.

• One or two 1.5-V batteries are to be used as the power source. Use one to begin with; if the volume of the buzzer is too low, add a second battery.
• The maximum length of the maze cannot exceed 18 inches.
• The amount of any additional wire required must be determined in advance and cut to the design specifications.
• The game participant must be able to hold the wand without touching any bare wires.
• The inner diameter of the conductive loop must be at least ⅜".
• The maze must stand on its own with one end of the wire supported by insulating material and the other end free.
• Any of the materials used in the Introductory Activity may be used to construct the game. Check with your instructor if other materials are desired.
• The rules of the game must be written out, including how the winner will be determined.
• The game should be challenging, yet not so difficult that a participant gives up too easily. Games should be fun!

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 wand be made?
3. List all the components of the game. Which ones will be part of the circuit?
4. During the game, what completes the circuit to make the buzzer sound? How will the other circuit components be arranged?
5. What possible safety hazards may exist and what precautions will you take to avoid those hazards?
6. How will you ensure the game is challenging, yet not so difficult that participants give up too easily? How will the winner be determined?
7. Brainstorm possible solutions to the challenge with your group. On a separate sheet of paper, draw sketches to represent your possible designs.
8. Choose the solution you believe will achieve the goal for the design challenge and that meets all the criteria and constraints.
9. Obtain the necessary materials and build the wire maze game according to your choice. Test and evaluate the game.
10. Attach a copy of your final sketch and the rules of the game to the worksheet. Be sure to label the parts of the game and show circuit connections.

Student Worksheet PDF

14004_Student1.pdf