Electrical Energy THE TEAK PROJECT: TRAVELING ENGINEERING ACTIVITY KITS. The TEAK Project Rochester Institute of Technology

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1 THE TEAK PROJECT: TRAVELING ENGINEERING ACTIVITY KITS Electrical Energy Partial support for this project was provided by the National Science Foundation's Course, Curriculum, and Laboratory Improvement (CCLI) program under Award No Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Partial support for this project was provided by the American Society for Heating, Refrigeration, and Air- Conditioning Engineering (ASHRAE) through a Senior Projects grant. Any opinions findings and conclusions or recommendations expressed here are those of the author(s) and do not necessarily reflect the views of ASHRAE The TEAK Project Rochester Institute of Technology

2 TEAK Electrical Energy Lesson Plan Page 2 ACTIVITY OVERVIEW Electrical Energy Kit Overview Students completing this kit will build several types of electrical circuits to learn about electrical energy. They will explore the differences between series and parallel circuits, make hypotheses about circuit performance, and take measurements to test their hypotheses. Activity Time Description Conductor and Insulator Word Sort Circuit Building Activity Lesson Extender: Capacitor Activity 5 min 30 min 25 min This activity allows the students to differentiate conductors and insulators while acknowledging similarities and differences. This activity allows the students to recreate several different types of circuits and analyze the effects of the circuit structure on voltage and current. Using several different capacitor sizes the students are asked to determine the effects of an LED on a capacitor. The discharge time for each capacitor bundle is then used to demonstrate how capacitors use the energy that has been stored inside of them. Learning Objectives By the end of this lesson, students should be able to Understand concepts related to electrical energy, voltage and current Understand series and parallel circuits Explain the functionality of a resistor Understand concepts related to electron flow, atoms and matter NYS Learning Standards Standard 4: Energy exists in many forms, and when these forms change energy is conserved. Describe a variety of forms of energy (e.g., heat, chemical, light) and the changes that occur in objects when they interact with those forms of energy. Observe the way one form of energy can be transformed into another form of energy present in common situations (e.g., mechanical to heat energy, mechanical to electrical energy, chemical to heat energy). The TEAK Project Rochester Institute of Technology

3 TEAK Electrical Energy Lesson Plan Page 3 TABLE OF CONTENTS Instructor Preparation Guide... 4 Pointers for Electrical Energy Kit... 4 Electrical Energy Activity Introduction... 6 Background Information... 6 Electricity Group Discussion... 6 Procedure... 8 Follow up Discussion... 8 Learning Objectives... 9 Materials for Each Group... 9 Safety Precautions... 9 Procedure... 9 Expected Results Concluding Discussion Electrical Energy Lesson Extender Capacitors Group Discussion Learning Objectives Materials for Each Group Procedure Expected Results Concluding Discussion Trouble-Shooting Guide Replacement of Parts Use of Multi-meters Current Activity Handout Parallel Circuit & Measuring Current Handout Capacitor Handout Image Sources Extended Resources Revisions Signifies Group Discussion Signifies Activity The TEAK Project Rochester Institute of Technology

4 TEAK Electrical Energy Lesson Plan Page 4 INSTRUCTOR PREPARATION GUIDE Pointers for Electrical Energy Kit Make sure you let the students know why they are sorting insulators vs. conductors. If possible, use the slideshow to explain the terms. If you can t use the slideshow, make sure you have another kind of visual - draw on the board, bring in printed sheets of parallel/series circuits etc. Try to keep everyone on the same challenge this way you can help them set up the multi-meters and make sure they are measuring the correct thing. Voltage Setting Current Setting Dial Dial Red Probe Red Probe Black Probe Black Probe It might be helpful to label the light bulbs on the physical boards When measuring the current, the light bulbs will dim The TEAK Project Rochester Institute of Technology

5 TEAK Electrical Energy Kit Lesson Plan Page 5 Electrical Energy DURATION 60 Minutes CONCEPTS Electrical Energy Atoms and Matter Electron Flow Series and Parallel Circuits Voltage and Current Resistors

6 TEAK Electrical Energy Kit Lesson Plan Page 6 ELECTRICAL ENERGY ACTIVITY INTRODUCTION Background Information Electricity is a form of energy produced by the movement of electrons. The movement of electrons induces an electric current from which power can be generated. Current can be sent through wires to produce light, supply power, or generate heat. Electricity Group Discussion (Pose the following questions to the group and let the discussion flow naturally try to give positive feedback to each child that contributes to the conversation.) Q: What do you have at home or school that runs on electricity? Toaster Microwave New Ovens with coils Computers Just to name a few Q: Where does electrical energy come from? Power plants (coal, nuclear) Batteries Portable generators Q: Do you know any alternative ways of producing electricity that are being developed today? Solar Hydro Wind Fuel Cell Geo-thermal Q: What kind of job do you think a person would have if they develop new ways of producing energy? Engineers and scientists

7 TEAK Electrical Energy Kit Lesson Plan Page 7 Electrical Circuit (Draw this circuit on the board to explain positive and negative connections and how they complete a circuit. Also explain the terms following the diagrams using the diagrams when necessary. Continue with discussion) Series Circuit Parallel Circuit Terms Electron: the negatively charged particle of an atom that is free to move around Electricity: the form of energy created by movement of electrons Conductor: a material that allows electricity to move through it easily Insulator: a material that does not allow electricity to pass through it easily Source: something that provides the circuit with power i.e. batteries Resistor: something that dissipates the energy i.e. light bulbs Voltage: the measure of the force pushing the electrons through a circuit o Example: if a tank of water were suspended one meter above the ground with a one-centimeter pipe coming out of the bottom, the water pressure would be similar to the force of a shower. If the same water tank were suspended 10 meters above the ground, the force of the water would be much greater, possibly enough to hurt you. (If you jumped from a one-meter diving board, the force when you hit the water would not be too great. If you jumped from a 10-meter board, the force would be much greater). Current: The flow of electrons o Example: if a water tank has a one centimeter diameter pipe coming out of it, less water can flow through it compared to the same tank with a 10 centimeter diameter pipe. Series: In order for the light bulbs to be in series, they have to be connected so the current only has one way to go. This makes the current the same through each light bulb. Parallel: In order for the light bulbs or resistors to be in parallel, the positive sides need to be connected together and the negative sides need to be connected together. This makes the voltage across each resistor the same.

8 TEAK Electrical Energy Kit Lesson Plan Page 8 Q: How do you know if the circuit is closed? The circuit is closed if current is flowing through all of the components. Think of Christmas lights. If one bulb goes out the circuit is no longer closed and the entire string goes out, but if all of the bulbs are on and working properly then current is flowing through the circuit. New style light bulbs have what is called a third strand cord so that there is always a closed circuit and will still light up even if one bulb goes out. Third strand cords have three wires instead of two in which the third wire connects all lights to keep the circuit flowing. Current Flow Everything on the planet wants to be in balance. Because there is a positive side to the source and a negative side, the electrons from the negative end of the source want to go to the positive end of the source. This movement of electrons is electrical energy! Q: Do you think we can build a circuit with string, pencils and some gum? An electrical circuit can only be made with objects or materials that electrical current can flow through - conductors. Conductor and Insulator Word Sort Activity 5 Minutes Procedure Allow groups to sort the given words into two groups to differentiate conductors vs. insulators Conductors: Insulators: Silver Glass Copper Rubber Gold Asphalt Aluminum Porcelain Iron Ceramic Steel Quartz Brass Plastic Bronze Air Mercury Diamond Follow up Discussion Q: Do you see something in common about all the conductors? They are all metals End Mini Activity

9 TEAK Electrical Energy Kit Lesson Plan Page 9 Circuit Activity 45 Minutes Learning Objectives By the end of this exercise, students should be able to Build and understand a basic circuit Use a multi-meter to measure voltage Materials for Each Group 1 Circuit Board Alligator Clips 1 Multi-meter 3 Light bulbs Safety Precautions Make sure ALL light bulbs are in place before students start constructing circuits. Procedure 1. Explain the kits before handing them out: On the circuit board, the red wire is the positive end of the battery and the black wire is the negative end of the battery. The alligator clips are all the same connecting wire; however the color can be used to organize positive and negative connections. Explain to the students that connecting the two ends of the battery directly will cause the circuit boards to short circuit (fail). 2. Now, hand out the kits. Instruct the students to take out only the circuit board, three light bulbs, and the alligator clips. Put everything else back in the box and place it on the floor. 3. Make sure that the students have ALL the light bulbs in place before they start connecting the battery. 4. Pass out the activity handout. 5. Instruct each of the groups to follow the instructions on the handout. 6. When they have finished, discuss their results with them. End Circuit Activity

10 TEAK Electrical Energy Kit Lesson Plan Page 10 Expected Results The students should observe that the current is lowered as more light bulbs are added to the circuit. Concluding Discussion Q: What did you notice about the voltage in the series circuits? What about the brightness of the bulbs? Q: What did you notice about the current in the parallel circuits? What about the brightness of the bulbs? Q: How did the brightness of the bulbs in the series setup compare to the brightness of the bulbs in the parallel setup? Q: Why would you want to use a circuit with components in series/parallel? In parallel all of the components have the same voltage In series all of the components have the same current Q: Did anyone know something was wrong at any given point? What did you change? How did you know to change that? Q: What kind of materials in your home could you use to create another electrical circuit?

11 TEAK Electrical Energy Kit Lesson Plan Page 11 ELECTRICAL ENERGY LESSON EXTENDER Capacitors Group Discussion (Pose the following questions to the group and let the discussion flow naturally try to give positive feedback to each child that contributes to the conversation.) Q: How does a battery work? A battery uses a chemical reaction to generate electrical energy. However because a battery creates power through a chemical process the speed at which it creates energy is limited. Q: How can power be stored? Power can be stored either in a rechargeable battery or in a capacitor. Q: What is a capacitor? A capacitor is the part of a circuit used to store charge (electrons) for a small amount of time, usually made of two metal plates separated by insulating material. A capacitor is similar to a battery. Capacitors and batteries both store energy. Here are a few differences between batteries and capacitors: Batteries: Make electrical energy Give off a small amount of electrical energy at a slow, constant rate Not always rechargeable Capacitors: Store electrical energy Give off large amount of electrical energy quickly Can be charged and discharged over and over o Think about when you scuff your feet on the floor. This builds up a charge and when you touch a doorknob the charge releases quickly. You can do this over and over. In an electronic circuit diagram, a capacitor is shown like this:

12 TEAK Electrical Energy Kit Lesson Plan Page 12 When you connect a capacitor to a battery, here's what happens: The capacitor end that is attached to the negative terminal of the battery accepts electrons. The capacitor end that is attached to the positive battery terminal loses electrons to the battery. Because one side of the capacitor now has more than the other there is a difference. This difference is called voltage. Think of the capacitor as a dam. And the battery as a river. More and more water builds up on one side, and on the other side there is no more water. The dam can only hold as much water as the river has. And once the dam is open the water flows through on its own. Once charged the capacitor has the same voltage as the power source that was charging it.

13 TEAK Electrical Energy Kit Lesson Plan Page 13 Capacitor Activity 30 Minutes Learning Objectives By the end of this exercise, students should be able to Understand the difference between capacitors and batteries Practice making circuits Learn about another common item in circuits, besides batteries and light bulbs. Materials for Each Group 1 Circuit Board Alligator Clips 3 Capacitor Bundles 1 Resistor 1 clear LED light Procedure 1. Instruct the students to take out only the circuit board, capacitors, resistor, LED light, and the alligator clips. Put everything else back in the box and place it on the floor. 2. Pass out the activity handout. 3. Instruct each of the groups to follow the instructions on the handout. 4. When they have finished, discuss their results with them. End Capacitor Activity

14 TEAK Electrical Energy Kit Lesson Plan Page 14 Expected Results The students should observe that the larger the capacitor bundles are, the longer the LED light will stay lit. Concluding Discussion Q: Which capacitor allowed the LED to stay lit the longest? Why did that happen? The biggest capacitor - it can store more electrical energy and use that energy over a longer period of time. Q: What did you notice about the current in the parallel circuits? What about the brightness of the bulbs? Capacitors: For larger power/short duration applications Batteries: For slow consistent discharge Q: Think of your parents car. Many things are run off electricity in a car. If you thought about the turn signals versus the headlights, which one would you need a capacitor for? Turn signals short flashes of light that are repeated, large amount of energy needed to make the light turn on Q: Can you think of anything that would use a capacitor? Surround Sound Speaker connections Turn on/off switches Flashes on cameras Computers (storing information) Defibrillator the machine doctors use to stimulate a stopped heart

15 TEAK Electrical Energy Kit Lesson Plan Page 15 TROUBLE-SHOOTING GUIDE Replacement of Parts Many circuit components will deteriorate over time, which may lead to failures. Specific problems may include: battery packs shorting, plastic melting, LEDs no longer working due to excess current being applied, inability of capacitors to hold electricity due to incorrect charging, and so on. If any of these occur, replacement parts may be found in the plastic bag. Use of Multi-meters For proper operation, make sure of the following: Leads are plugged in to the correct ports The knob is turned to DCV 20 The pointed ends are being pressed onto a positive and negative end A 9-volt battery (inside the multi-meter) may need to be replaced

16 TEAK Electrical Energy Kit Lesson Plan Page 16 CURRENT ACTIVITY HANDOUT Before using any alligator clips, put ALL three light bulbs in place Series Circuits & Measuring Voltage 1. Construct a closed series circuit as shown in Circuit A. **Note: the red wire is the positive end of the battery and the black wire is the negative end of the battery Circuit A Circuit B Circuit C 2. Measure and record the voltage across light bulb 1 by placing the tips of each lead from the multi-meter on the wing nuts on either side of the light bulb. 3. Construct a closed series circuit as shown in Circuit B. 4. Measure and record the voltage across light bulb 1 and then light bulb Construct a closed series circuit as shown in Circuit C. 6. Measure and record the voltage across light bulb 1, light bulb 2 then light bulb 3. Light Bulb 1 Light Bulb 2 Light Bulb 3 Voltage (V) Circuit A Circuit B Circuit C

17 TEAK Electrical Energy Kit Lesson Plan Page 17 PARALLEL CIRCUIT & MEASURING CURRENT HANDOUT 1. Construct a closed parallel circuit as shown in Circuit X. Circuit X Circuit Y Circuit Z 2. Measure and record the current through light bulb 1 a. Unclip the red alligator clip from light bulb 1 and clip it to the red lead of the multimeter. b. Place the tip of the black lead from the multi-meter to the nut you unclipped the red alligator clip from. 3. Construct a closed parallel circuit as shown in Circuit Y. 4. Measure and record the current through light bulb 1, and then light bulb 2. a. To measure through light bulb 1 refer to step 2 b. To measure through light bulb 2 i. Unclip the red alligator clip from light bulb 2 and clip it to the red lead of the multi-meter. ii. Place the tip of the black lead from the multi-meter to the nut you unclipped the red alligator clip from. 5. Construct a closed parallel circuit as shown in Circuit Z. 6. Measure and record the current across light bulb 1, light bulb 2, and then light bulb 3. a. To measure through light bulb 1 refer to step 2 b. To measure through light bulb 2 refer to step 4b c. To measure through light bulb 3 i. Unclip the red alligator clip from light bulb 3 and clip it to the red lead of the multi-meter. ii. Place the tip of the black lead from the multi-meter to the nut you unclipped the red alligator clip from. Current (A) Circuit X Circuit Y Circuit Z Light Bulb 1 Light Bulb 2 Light Bulb 3 ** If you have extra time, measure the voltage across each light bulb in circuit Z and make an observation ** Extra Challenge: Series and Parallel Circuit See if your group can create a circuit that is both parallel and series. How can you test your circuit to see if it is both parallel and series? Make a sketch on a separate piece of paper.

18 TEAK Electrical Energy Kit Lesson Plan Page 18 CAPACITOR HANDOUT To charge the capacitor: 1. Using alligator clips, connect the battery to the capacitor, creating a complete circuit. The red side of the capacitor (positive) should match the red side of the battery. Keep the circuit connected for at least 20 seconds to fully charge your capacitor. Disconnect from battery. To use the capacitor: 2. Using alligator clips, connect the positive side of the capacitor (red) to one end of the resistor (needed to regulate the power from the capacitor so the light doesn t burn out). 3. Connect the negative side of the capacitor (black) to the red wire of the LED. 4. Have one member of your group cup their hands around the light and prepare to count out loud how many seconds it stays lit up. 5. Have another group member connect the other end of the light to the other end of the resistor. The completed circuit will look kind of like this: 6. Record the number of seconds in the chart below. 7. Remove the capacitor from the circuit and recharge it. 8. Using steps 1-6, perform the experiment twice for each capacitor bundle. 9. Calculate the values for the last column. Bundles: Trial #1 Trial #2 Dark Blue Capacitor Dark Blue with 2 Light Blue Capacitors 3 Dark Blue Capacitors Average (#1 + #2) 2

19 TEAK Electrical Energy Kit Lesson Plan Page 19 IMAGE SOURCES [1] BBC. A Complete Circuit JPEG file. [2] Brain, Marshall and Bryant, Charles W. How Capacitors Work JPEG file. EXTENDED RESOURCES New York State Standards Introduction to DC Circuits Introduction to Capacitors Exploring Science and Technology REVISIONS Date Changes Made Changes Made By 9/10/09 -Updated capacitor section (lesson plan & handout) 4/9/13 Updated format and edited for grammar and syntax mistakes Heather Godlewski Todd Jackson