WIND TURBINE DESIGN AND TESTING ACTIVITY

LevelElementaryGrades K-4WIND TURBINEDESIGN AND TESTINGImage credit: Artville 2014 National Geographic Society. All rights reserved. ACTIVITY: WIND TURBINE DESIGN AND TESTINGBig IdeaStudents will learn how the power of the wind is harnessed and used to make electricity.Guiding QuestionHow do engineers create useful power from the wind?Materials Gathered by Teacher1.Fan2. Scrap stiff paper (e.g. card stock, cardboard cereal boxes, etc.)3. Scissors: 1 pair for every 4 students (Most students in elementary classrooms have scissors or the teacher has aclassroom set.)4. Clear or masking tape: 1 roll per classroom5. Projector: a way to share the online videoMaterials Provided in the EITC Kit1.Motor (2 per kit)1.Electrical wires (2 one-foot red wires and 2 one-foot black wires)1.Alligator clips (8 per kit)1.LED Bulb (2 per kit)1.Corks (1 per group)2. Toothpicks (10 per group)Set UpCommunicate with the teacher at least one week before your scheduled classroom visit. Inform the teacher that thisactivity will require an indoor workspace. For the indoor portion of this visit, desks should be arranged so students canalternate between small-group work and all-class discussions and demonstrations.For the complete activity andmedia resources, please visit:www.classroomengineers.orgPage 1 of 8

2014 National Geographic Society. All rights reserved.LevelElementaryGrades K-4 WIND TURBINE DESIGNAND TESTINGIntroductionTeacher introduces the engineer/classroom visitor.Setting the Stage Show the introductory video Tell students who you are, what you do, and what it’s like to work in your career (3 minutes). Tell them a story about how you got interested in engineering/your career or something that happened in your workthat was really exciting—something that truly made a difference in your life (3 minutes). Ask students if they know what a wind turbine is. Allow time for as many responses as possible. Then you can tellstudents that a wind turbine works the opposite of a fan. Instead of using electricity to make wind, a turbine uses windto make electricity. Show a wind turbine video clip.Hands-on ActivityBriefly discuss students’ prior knowledge of sources of electricity and how wind energy works.Ask: Have you ever wondered how the wind is used to make power for our homes and cities? Tell students that windturbines are marvels of engineering (amazing machines), but the idea of using the wind to produce power startedthousands of years ago as simple machines much like what they will be building today.Briefly explain that air currents (flowing air) on Earth naturally create wind. Think about a time when you have stoodoutside on a windy day and your body felt the power of the wind. Since the first century a.d. or earlier, humans haveinvented machines to use wind power. Modern wind turbines have blades half the length of a football field to useas much wind power as possible. The spinning blades connect to a generator to create electricity for us to use. Agenerator is a machine that makes electricity.Ask: If the wind is constantly changing, how do wind turbines keep making power?Explain: Because most wind turbines are very large, small changes in the wind have little effect on the wind turbine. Forlarge wind changes, wind turbines can be adjusted to keep them spinning at the correct speed. The wind turbine hassensors that tell the onboard computer the wind speed and wind direction. A sensor is a device that detects or sensesheat, light, sound, motion, etc. The computer can turn the entire wind turbine head to face the direction of the wind.As the wind blows lighter or stronger, the angle of the blades, known as pitch, can be changed to help the turbine spinfaster or slower. If the wind is blowing really strong, a brake keeps the turbine from spinning too fast.Lockheed Martin measures the wind very accurately to find the best places to build new groups of wind turbines, knownas wind farms. Wind farms are places where the wind blows consistently and are able to produce the most energy fromwind turbines.Students design and make wind turbine blades.Explain to students that they are going to design and build a turbine rotor, which is the part of the wind turbine thatspins with the wind. They are going to decide the size, shape, and pitch of their blades as well as the number of bladesto connect to their cork. The rotor will be connected to a simple generator and held in the fan-generated wind. As therotor spins, the generator will create electricity to light an LED light bulb.Ask the teacher to divide students into groups of three. Ask one or more student volunteers to pass out materials toeach group including 1 pair of scissors, 1 cork, tape, toothpicks, and stiff paper for the blades. Advise students thatthey can cut blades into the shape of the template or another shape of their choosing. Demonstrate cutting out ablade and using it as a template for cutting the next blade the same size. Tell students it’s important that once theyselect a blade shape and size, the rest of the blades need to be nearly identical. Then demonstrate taping a blade to atoothpick. Explain that once the blades are cut out, students will tape each blade to a toothpick. Once all of the bladesare mounted on toothpicks, press the toothpicks into the cork with each blade having approximately the same pitch(angle). Explain and demonstrate that students should try to make the turbine as symmetrical as possible. This makesthe turbine more balanced and helps it spin faster.For the complete activity andmedia resources, please visit:www.classroomengineers.orgPage 2 of 8

2014 National Geographic Society. All rights reserved.LevelElementaryGrades K-4 WIND TURBINE DESIGNAND TESTINGStudents test their wind turbines.As groups finish assembling their wind turbine rotors, call them up to the fan to test their creations. You or the teacherwill press the axle of the motor into the cork as near to the center as possible. Ask one student to hold the motor andface the turbine toward the fan (wind). The other students will hold the LED bulb and observe the amount of lightgenerated. After each test, disconnect the rotor from the motor shaft and let the groups try to modify (change) theirrotors to work better; try using more/fewer blades, smaller/larger blades, more/less pitch angle, and better balance.Each group should be able to test and modify their turbine 2 to 3 times. Ask students to write down how their changesaffected the results. Did the turbine look like it spun faster or slower? Did the light look brighter or dimmer?Wrap-UpHave students bring the leftover material to the front of the room and place it in the appropriate location. While thematerials are being put away, make a table on the white board and label the top row with the group numbers (seeexample of chart in the resource carousel). Once students have all returned to their groups, ask group 1 how manyblades their first wind turbine design had and write the number under the group 1 column. Next ask group 1 what theychanged when they modified their design using as few words as possible (e.g., changed blade pitch, number of blades,made it more symmetrical, made blades smaller/larger). Ask them which design worked the best and put a star in thatrow (see example chart in the resource carousel). Do this for the remaining groups.Ask students questions about what they discovered about designing and building windmills. How many blades didmost groups choose? Did more or less pitch work better? Did smaller or larger blades work better? How important wassymmetry and balance? Explain that symmetry is when one shape becomes exactly like another if you flip, slide, or turn it.Emphasize that what worked best in the experiment was specific to the test conditions. To design real wind turbines,engineers must consider many things. Ask students to name examples of what they would have to consider whendesigning a real wind turbine for a specific location. Students should come up with most of the following criteria.When they have completed their list, offer them the examples they did not mention: The normal wind speed The maximum wind speed How far the wind turbine will be from where the electricity will be used How big the wind turbine blades can be without breaking The cost to build the turbine How often their wind turbine would need to be maintained/fixedFor the complete activity andmedia resources, please visit:www.classroomengineers.orgPage 3 of 8

2014 National Geographic Society. All rights reserved.LevelElementaryGrades K-4 WIND TURBINE DESIGNAND TESTINGSUPPORT MATERIALS—FOR THE CLASSROOM VISITORBackground InformationAir currents on Earth naturally generate wind. The wind’s power can be felt pushing against the human body just bystanding outside on a very windy day. Since the first century a.d. or earlier, humans have invented machines to harnessthat wind power. Many of the early devices were designed to mill grain and so the name windmill was often used.Modern devices harness wind to produce electricity and are called wind turbines.Wind turbines are designed with their axis of rotation either horizontal (like a windmill) or vertical with respect to theground. This activity will focus on a horizontal axis wind turbine. This turbine consists of a rotor with two or more bladesattached. The rotor connects to the main shaft, which turns the gearbox. The gearbox increases the rotation speed tothen drive the generator, which creates electricity.Because the wind turbine blades and rotors are very large (some modern wind turbines have blades half the length of afootball field!) and have a lot of momentum, short gusts or lulls in the wind have little effect on the rotational speed. Forlarge wind changes, wind turbines have features that can be adjusted to keep the rotational speed at the desired level.The wind turbine has sensors that feed wind speed and direction information to an onboard computer. The computer isprogrammed to use this data to make adjustments to the wind turbine. Some adjustments may include the following: The entire head of the wind turbine can turn to face the direction of the wind. The pitch (angle) of the blades can be adjusted to increase or decrease the rotational force generated by the wind. The main shaft of the turbine has a brake that slows the rotor during high-wind conditions.In designing wind turbines, engineers must consider many environmental conditions, constraints, and goals.Examples of wind turbine design considerations include the following: The normal wind speed The maximum wind speed The distance from the wind turbine to where the electricity will be used The size of the wind turbine The cost to build the wind turbine Maintenance of the wind turbine Environmental effects of the wind turbineLockheed Martin has developed technology to assess the wind energy at potential wind farm locations and help definesome of the previously mentioned design considerations. Locations with more consistent wind direction and speed willproduce the most energy from wind turbines.National Standards Alignment National Science Education Standard (K–4) Standard A-1: Abilities necessary to do scientific inquiry National Science Education Standard (K–4) Standard E-2: Understandings about science and technologyNext Generation Science Standards (K–2) ETS1B: Developing possible solutions ETS1C: Optimizing the design solutionFor the complete activity andmedia resources, please visit:www.classroomengineers.orgPage 4 of 8