Energy from Wind Turbines Activity Guide

CWSE- ON Activities 2010

Energy from Wind Turbines

An Activity Guide for Grade 4-6 Teachers

Energy From Wind Turbines

Table of Contents

Introduction ............................................................................................................................................ 3

Curriculum Links – from Revised 2007/2008 Ontario Curriculum .............................. 3

Theory & Background Information (for Teachers) ............................................................ 5

Wind Turbines ........................................................................................................................................... 5

How does a Wind Turbine Work? ........................................................................................................ 5

RPM to Voltage ......................................................................................................................................... 6

Power (Watts and Kilowatts) .................................................................................................................... 7

Preparation (for teachers): ............................................................................................................. 9

Activity Instructions: ....................................................................................................................... 10

Instructions (for students): ......................................................................................................... 11

Testing .................................................................................................................................................... 12

Safety Considerations .................................................................................................................... 12

Worksheets ........................................................................................................................................... 13

Resources ............................................................................................................................................. 13

References ............................................................................................................................................ 13

APPENDIX C ......................................................................................................................................... 16

APPENDIX D ......................................................................................................................................... 18

APPENDIX E ......................................................................................................................................... 19

APPENDIX F .......................................................................................................................................... 20

APPENDIX G ......................................................................................................................................... 21

Acknowledgement: The Chair for Women in Science and Engineering ‐ Ontario (CWSE‐ON) is generously

supported by the Natural Sciences and Engineering Research Council, Research in Motion and the

University of Guelph.

Introduction This workshop is specifically designed to bring a new, hands‐on activity into science classrooms. “Energy from Wind Turbines” challenges students to apply what they learn in class to design, build and test their own working wind turbine. This activity can easily be integrated into elementary science classes because it reinforces many of the topics covered in the Ontario Science Curriculum, particularly at the Grade 5 and 6 levels. In the workshop students will learn about forms of energy, electrical devices, power, voltage, and energy transformations. They will discover the importance of problem solving and creativity in science, engineering and technology. Finally they will understand how the material they learn in class can apply to real world challenges. The best part about this workshop is its simplicity. The required equipment and materials can be purchased at low cost. The instructions are straight forward so that both students and teachers should have no problem following them. This guide includes everything teachers need to know bring “Energy from Wind Turbines” into their classrooms. It includes links to the 2007/2008 curriculum, theory and background information, detailed instructions, worksheets, templates and useful internet links.

Topic (s) Wind Turbines, Energy Transformations, Electricity, Engineering

Grade Level 5‐6

Cost (per class) Equipment (motor, multimeter): approximately $15 (one‐time cost) Consumable materials (corks, straws, tape): $3‐$5

Time (preparation and activity) 3‐5 hours prep, 2‐4 hour activity (depending on age group)

Complexity Medium

Curriculum Links – from Revised 2007/2008 Ontario Curriculum This section shows how Energy from Wind Turbines fits into the grade 5 and 6 curriculum. The following points have been copied directly from the 2007/2008 Ontario Science Curriculum document.

Understanding Earth and Space Systems: Grade 5 – Conservation of Energy and Resources 1.1 analyze the long‐term impacts on society and the environment of human uses of energy

and natural resources, and suggest ways to reduce these impacts (e.g., turning off the faucet while brushing teeth or washing and rinsing dishes conserves water; reusing or recycling products, or using fewer products, conserves natural resources and energy)

1.2 evaluate the effects of various technologies on energy consumption 2.3 use technological problem‐solving skills (see page 16) to design, build, and test a device

that transforms one form of energy into another (e.g., create a child's toy that uses the electrical energy from a battery or solar cell to move across the floor [kinetic energy] and make a noise [sound energy]), and examine ways in which energy is being "lost" in the device. Sample guiding questions: Describe the energy transformations that are taking place in your device. What challenges did you encounter in making these transformations take place? As one form of

energy is being transformed into another, where is energy being lost in your device? How might you minimize that loss?

2.4 use appropriate science and technology vocabulary, including energy, heat, light, sound, electrical, mechanical, and chemical, in oral and written communication

2.5 use a variety of forms (e.g., oral, written, graphic, multimedia) to communicate with different audiences and for a variety of purposes (e.g., in a small group, discuss ways in which technological innovations increase and/or decrease our ability to conserve energy)

3.1 identify a variety of forms of energy (e.g., electrical, chemical, mechanical, heat, light, kinetic) and give examples from everyday life of how that energy is used (e.g., electrical energy for cooking; chemical/electrical energy to run our cars; mechanical energy to hit a baseball; light energy for managing traffic on the roads; heat energy to warm homes and schools)

3.2 identify renewable and non‐renewable sources of energy (e.g., renewable: sun, wind, ocean waves and tides, wood; non‐renewable: fossil fuels such as coal and natural gas)

3.3 describe how energy is stored and transformed in a given device or system (e.g., in a portable electric device, chemical energy stored in a battery is transformed into electrical energy and then into other forms of energy such as mechanical, sound, and/or light energy)

3.4 recognize that energy cannot be created or destroyed but can only be changed from one form to another (e.g., chemical energy in a battery becomes electrical energy)

3.5 explain that energy that is apparently "lost" from a system has been transformed into other energy forms (usually heat or sound) that are not useful to the system (e.g., sound from a car's engine does not help the car move)

Understanding Matter and Energy: Grade 6 – Electricity and Electrical Devices 1.1 Assess the short‐ and long‐term environmental effects of the different ways in which

electricity is generated in Canada (e.g., hydro, thermal, nuclear, wind, solar), including the effect of each method on natural resources and living things in the environment

2.4 Design, build, and test a device that produces electricity (e.g., a battery built from a lemon or potato; a wind turbine)

Sample guiding questions: How does a wind turbine produce electricity? Is this a good method of producing electricity? Why? Why not?

2.5 Use technological problem‐solving skills (see page 16) to design, build, and test a device that transforms electrical energy into another form of energy in order to perform a function (e.g., a device that makes a sound, that moves, that lights up). Sample guiding questions: What function will your device perform? What does your device transform the electrical energy into? How does your device work?

2.6 use appropriate science and technology vocabulary, including current, battery, circuit, transform, static, electrostatic, and energy, in oral and written communication

2.7 use a variety of forms (e.g., oral, written, graphic, multimedia) to communicate with different audiences and for a variety of purposes (e.g., using scientific and technological conventions, create a labeled diagram showing the component parts of the device they created to transform electrical energy into another form of energy and perform a function)

3.4 describe how various forms of energy can be transformed into electrical energy (e.g., batteries use chemical energy; hydroelectric plants use water power; nuclear generating stations use nuclear energy; wind turbines use wind power; solar panels use energy from the sun; wave power stations use energy from ocean waves)

3.5 identify ways in which electrical energy is transformed into other forms of energy (e.g., electrical energy is transformed into heat energy in a toaster, light and sound energy in a television, mechanical energy in a blender)

3.6 explain the functions of the components of a simple electrical circuit (e.g., a battery is the power source; a length of wire is the conductor that carries the electrical current to the load; a light bulb or motor is the load)

3.8 describe ways in which the use of electricity by society, including the amount of electrical energy used, has changed over time (e.g., drying clothes in a dryer instead of using a clothesline; playing video games instead of playing board games; using electric lights instead of candles)

Theory & Background Information (for Teachers) Wind Turbines People have been using wind power for thousands of years. Some historians claim the sail boat was the first machine to harness wind power. There is evidence that sail boats were used in ancient Egypt to carry cargo along the Nile River. At this time (around 3200 B.C.) the sails were made out of reeds and leaves. The first known use of wind turbine is in Persia around 700 A.D. Since that time, there is evidence that people used wind turbines all over the world. The early windmills were used mainly for pumping water, grinding grain and irrigating the land. It wasn’t until electrical devices were invented and that people started to use wind turbines to generate electricity. Today, wind turbines come in all different shapes and sizes but generally their basic components are the same.

How does a Wind Turbine Work? Wind turbines convert wind energy into electrical energy. The blades (see Figure 1) are designed to turn when wind hits them. Part of the reason why they turn is because of something called pitch. Pitch refers to the angle of attack that the blades make with the wind. The rotational speed of the blades can be controlled by adjusted pitch of the blade. The blades are part of a unit called the rotor. The rotor consist of the turbines’ external rotating parts. Wind energy is transformed into mechanical energy when the rotor is spinning. The rotor is connected to a low‐speed shaft. The low‐speed shaft is found inside of the turbines’ gear box. When the rotor turns, the low‐speed shaft turns too. This low‐speed shaft drives a large gear and a small gear. The large gear turns at the same rate as the low‐speed shaft, but the small gear rotates at a much higher speed.

The rotation of this smaller gear drives the high‐speed shaft connected to the generator. When the high speed shaft is turning, the generator is generating electricity. The amount of electrical energy produced depends on how fast the high‐speed shaft is turning. The generator transforms mechanical energy into electrical energy.

Figure 1 Parts of a wind turbine. Source: http://www.alliantenergykids.com/EnergyandTheEnvironment/RenewableEnergy/022397

Other parts of a wind turbine: Brake: If the wind is to strong the brake is used to slow down the blades to prevent damage Yaw drive and motor: Turns the turbine so that it faces oncoming wind Tower: Gives the blades height, exposing the turbine to higher wind speeds Controller: This is like the brain of the wind turbine. It controls the different parts of the turbine (the yaw motor, brake, rotation of the blades, and direction the turbine is facing) Anemometer: Determines the wind speed Wind Vane: Determines the wind direction Nacelle: Covers the internal components

RPM to Voltage In this activity students will be creating basic wind turbines. They will not be using gears and high/ low speed shafts. The blades will be connected directly to a rotor that is mounted on the generator shaft. This means that when the blades turn, the shaft on the generator is turning along with them. The blades and the generator shaft will be turning at the same speed.

When the blades are spinning, the parts inside the generator are spinning too. In the generator, magnets turn inside coils of copper wire. When the magnets turn they create an electrical force across the wire. This electrical force is called voltage and this is what the multimeter will be measuring. The speed of rotation of the blades is directly related to the voltage output. The faster the blades are spinning, the greater the electrical force will be. Even without a multimeter, students can get some indication of how well their turbine is performing by measuring the number of revolutions per minute (RPM) their blades make. An easy way to measure RPM:

1. Color one blade a different color from the rest of the blades. 2. Count how many times that colored blade passes in front of the edge of the desk during 20

seconds. 3. Multiply this number by 3. This is the turbine’s RPM.

Power (Watts and Kilowatts) A Watt (W) is a unit of electrical power. Power is the amount of energy produced or consumed per second. The power output generated by wind turbines is most often reported in Kilowatts (kW). A Kilowatt is 1000 Watts. The range of power output generated by wind turbines depends on the size of the turbine. A smaller turbine with a rotor diameter of 10 meters may generate around 25 kW while a larger turbine with a rotor diameter of 80 meters could generate around 2500 kW. How to Use a Digital Multimeter Most multimeters can measure the current, voltage and resistance of an electrical device. This activity

will be focusing on measuring the voltage generated by students wind turbines. Parts of a digital multimeter (refer to figure on next page): Test Leads: There are two test leads. Usually one lead is black and one is red. These are connected to the generator to take a reading. Screen: Shows the reading Jacks (on some digital multimeters): The test leads are inserted into the jacks to connect them to the multimeter. On some meters these are permanently connected. Often a multimeter will have two jacks, occasionally there are three. The black lead is inserted into the jack labeled “COM” or (‐). This is the negative lead. The red lead is connected to the jack labeled with a VΩA (volts, ohms, amps), VΩmV (volts, ohms, millivolts) or with a (+) sign. This is the positive lead.

Rotating switch: Allows the user to choose what is being measured (voltage, current, resistance) and the measurement scale. Common markings around the rotating switch: Ω : Ohms (resistance) A : DC amps (current) V : DC volts (voltage) V ~ : AC volts (voltage)

: Diode Test In this activity students will measure the DC voltage generated by their wind turbines. This means that when the multimeter is in use it should be switched to V position. The numbers beside the V indicate the maximum voltage that can be measured in that position. For example, when the digital multimeter is set to 2000 m this mean that the maximum DC voltage that will be displayed on the screen is 2000 mV (millivolts). Since the student’s wind turbines will generate a small voltage, the multimeters can be switched to the second smallest value. On most digital multimeters this will 2000 m, meaning 2000 mV. To take a reading with the meter touch the test leads to the ends of the generator wires. The voltage will be shown on the screen. Remember that the units should millivolts for this activity.

Troubleshooting: Problem: During testing, the voltage shown on the screen is negative. The test leads may be reversed. Switch the connection between the test leads and the generator wires to fix this problem. Regardless of whether there is a negative sign or not the voltage value will be the same. This means that it is not necessary to switch the test leads to get the correct voltage value. When recording the value simply ignore the negative sign.

Problem: During testing, the voltage goes up and down and does not stabilize This may occur for a number of reasons: imperfections in the generator, off balance blades, inconsistent wind, etc. Do not worry too much about stabilizing the value. Teachers should just pick the most frequent value or highest value that appears (depending what they prefer). Summary:

1. Switch the rotating switch to 200m or 2000m in the V position. 2. Touch the testing leads to the ends of the generators wires 3. Record the voltage displayed on the screen in millivolts

Preparation (for teachers):

Equipment (for teacher preparation) Generator (1.5‐3V motor recommended)

Tapered Cork

Multimeter

Fan/ hair dryer

Electrical tape and/or alligator clips

The testing apparatus:

The testing apparatus should be assembled and tested before students build their turbines. The testing apparatus consists of a multimeter, ruler, generator and a cork. There will be one testing apparatus for the class.

Figure 2 Test apparatus set‐up

Test apparatus set‐up:

1. Attach the cork to the generator: Use a skewer or pin to poke a hole in the center of the cork. Insert the generator shaft into this hole.

This is the most important step in the set‐up. The generator shaft needs to be inserted exactly in the center of the cork. If the cork is not centered it will affect the rotation and performance of the students turbines. Use the guide and template in Appendix A to center the hole.

2. Tape the generator to a long ruler or meter stick: Make sure that the generator is attached at the end of the ruler so that shaft extends beyond the ruler edge and the cork can move freely without hitting the ruler.

3. Attach the ruler to a sturdy surface: Use tape to secure the ruler to the edge of a table or desk. The cork should extend off the table so that when the blades are attached they do not hit the table.

4. Attach the multimeter: Use electrical tape or alligator clips to attach the wires from the generator to the test leads.

Before going through the workshop with the class, it is important to test the multimeter, wind source and generator to make sure everything is working properly. Test blades with a fan or hair dryer to see how everything works. Check‐list:

The multimeter gives a reading on the screen when it is on and the blades are spinning

The cork is centered

The blades are not hitting the table when they spin

Other Preparations:

In addition to preparing the test set up the teacher will have to print out ring templates for the class. The Ring Template page can be found in Appendix B. The teacher should print out enough pages so that each student gets one ring. During the activity students will be tracing this ring onto a thinker stock of paper (cardboard or Bristol board). They will be attaching their blades to this ring.

Note: Before printing out enough rings for the class make sure that the ring is the right size for the cork. The rings should slide a few centimeters over the narrower end of the cork toward the wider end. The ring should fit snugly on the cork. If the rings from the Ring Template page are too big or small for the cork that is being used, the size will have to be adjusted. In this case teacher will have to create a new template.

Activity Instructions:

Materials (per student) 1‐ 6 straws

Thin cardboard or Bristol board for ring (cereal boxes work well)

Masking tape

Scissors

Various stocks of paper for blades (student can choose from various stocks; cardboard, Bristol board, printer paper, etc)

Students will decide on the shape of the blades and the material that they are made of. Encourage students to be creative and let them know that many different designs are possible.

Instructions (for students):

1. 2. Cut your paper ring template

1) Cut out the ring template 2) Trace the ring template on cardboard

3) Cut out the cardboard ring 4) Draw your blades

5) Cut out your blades 6) Tape each of your blades to a straw

Testing Each student tests the rotor they have made.

1. The student slides the rotor over the narrow end of the cork until it fits snugly. This is shown in step 8 of the student instructions (above).

2. Turn the digital multimeter on and switch the rotating switch to the second lowest number in

the DC voltage section. To do this, look for the V symbol (DC voltage) then switch it to 2000 m (for millivolts). At this setting, the multimeter will display voltages between 0 mV and 2000 mV. This range should be suitable for the majority of the students’ turbine blades. If students’ blades are turning very slowly, the teacher may want to switch the rotating switch to 200 m. At this setting the multimeter displays voltages between 0.0 mV and 200.0 mV. See the background information on multimeters for additional information.

3. Place the fan/ hair dryer (wind source) in front of the wind turbine and turn it on. It is up to the

teacher to decide if they want to keep wind source at a set distance or if the students will be able to move it around. The advantage of having a stationary wind source is that the results are consistent. The advantage of having a mobile wind source is that students generally get better voltage output results.

4. Observe and record the voltage output on the multimeter’s display screen.

Appendix C and D include Results and Discussion worksheets. Teachers should feel free to use, modify

and distribute these worksheets to their students. Safety Considerations

Students will be working with scissors to cut thick paper. Advise students to ask for assistance if they need it.

7) Tape the ends of the straws onto the 8) When finished, push the rotor onto the cardboard ring to make a rotor. cork for testing

During testing students are working with rotating parts (turbine blades). Advise students to stand back from the test set up when the fan is on.

During testing students are working with a fan and/ or hairdryer. Students should not stick anything (pencils, fingers, paper, etc) inside these objects at any time.

Students will be working with multimeters. These should not be used to test objects, other than the generator that is provided in the workshop, without permission from the teacher.

Students will be working with electrical components. These components should not be used for any other purpose other than what the above instructions specify.

Worksheets This activity reinforces many of the topics in the grade 5 and 6 Ontario Science curriculum. To help teachers integrate this activity into their lesson plan, several worksheets have been provided in this guide. Teachers should feel free to use, modify and distribute these worksheets. The worksheets are found in Appendices E through G.

Resources Ontario Chair for Women in Science and Engineering: http://www.cwse‐on.ca/?resourceID=1 Engineering activities: http://www.teachengineering.com/ Wind energy lesson plans, activities and resources: http://www.kidwind.org/students_teachers/ Additional information about wind turbines: http://science.howstuffworks.com/environmental/green‐science/wind‐power.htm

References Canada. Ministry of Education. The Ontario Science Curriculum Grades 1‐8. Ontario: 2007. Available at: http://www.edu.gov.on.ca/eng/curriculum/elementary/scientec.html. Accessed: 12 April 2010. Carlson, Denise, et al. “TE Activity: Wind Power.” teachengineering.com. 26 September 2008. 10 March 2010.<http://www.teachengineering.com/view_activity.php?url=http://www.teachengineering.com/collection/cub_/activities/cub_energy2/cub_energy2_lesson07_activity2.xml> “Estimating Appliance and Home Electronic Use” energysavers.gov 24 March 2009. U.S. Department of Energy. 31 August 2010. <http://www.energysavers.gov/your_home/appliances/index.cfm/mytopic=10040> Gibson, Diane. Wind Power. Minnesota: Smart Apple Media, 2002. Layton, Julia. "How Wind Power Works" HowStuffWorks.com. 06 August 2006. Discovery Chanel. 30 August 2010.<http://science.howstuffworks.com/environmental/green‐science/wind‐power.htm> “Multimeters” The Electronics Club. 30 August 2010. <http://www.kpsec.freeuk.com/multimtr.htm> Walker, Niki. Generating Wind Power. St. Catharines: Crabtree Publishing, 2007. “Wind Turbines” Wind Solar Energy. 2008. 30 August 2010 <http://www.windsolarenergy.or g/windturbines.htm>

APPENDIX A: Centering Circle Template It is important to make the hole for the generator shaft exactly in the center of the cork. Use this template to help make the hole.

1. Place the wider end of a tapered cork against the centering circle template. 2. Find the circle that is the closest to the diameter of the cork on the template. 3. Trace that circle. 4. Cut out the circle and glue it to the wide end of a tapered cork 5. Insert a pin or skewer through the center of the X in the centering circle to make

a hole for the generator shaft

Centering Circle:

APPENDIX B: Ring Template

APPENDIX C

RESULTS AND DISCUSSION

1. VOLTAGE My best voltage was mV 2. SHAPE

Draw your blade here: Why did you choose this shape? Was this shape a good choice? (Why or why not?)

3. MATERIAL PROPERTIES My blade is: Stiff Flexible My blade is: Light Heavy

Why did you choose this material? Was this material a good choice? (Why or why not?)

4. ANGLE

How did you angle your blades (use the check boxes): Facing the fan (no angle) On an angle to the fan Do you think changing the angle of the blades makes a difference to how fast the turbine spins? Why or why not?

5. IMPROVEMENTS If you did this project again, what would you change about your design?

APPENDIX D

RESULTS AND DISCUSSION

Design 1 Design 2

Sketch of the Blade Shape

Observations

Highest Observed Voltage

Problems

Solution

APPENDIX E

WATTS, KILOWATTS AND WIND TURBINES

Questions:

1. How many kilowatts (kW) is 2000 watts (W)?

2. How many watts is 4 kilowatts?

3. If a wind turbine generates 25 000 W of power, how many of the TVs could it

power?

4. How much power would be required to turn on two toasters and one computer?

5. How many kW does the microwave require?

6. If you wanted to turn on all five items above, how much power would your wind turbine need to supply?

7. If a wind turbine generated 100 kW of power how many light bulbs could it turn on?

8. Pick one appliance in your home and find out how much power it requires to run.

9. For the appliance you choose in number 8: how many could be powered by a 30 kW wind turbine?

Light Bulb

Microwave

1 500 W

Toaster

Computer

Remember: 1 000 Watts (W) =

1 kilowatt (kW)

APPENDIX F

WIND TURBINES TRANSFORM ENERGY

PART 1: Label the wind turbine using these words:

Gear Shaft Rotor Tower Blade Wind Generator

PART 2: Answer the following questions:

1. Describe how a wind turbine produces electricity. Make sure to say what energy transformations occurring.

2. How many watts is a kilowatt? How many watts is a megawatt?

3. How many 60 watt light bulbs could a 24 kilowatt wind turbine power?

4. Give three reasons why wind turbines are a good way to generate electricity.

APPENDIX G

ENERGY TRANSFORMS

1. Describe four energy transformations that you see in this picture.

2. Identify three devices in your home that use electrical energy as their source.

3. Make a list of the different ways electrical energy is generated in Ontario.

4. Describe two ways that wind turbines impact the environment. These impacts can be positive or negative.

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