Windmills vs. Wind Turbines

Windmills vs. Wind Turbines

Target Grade Level / Age Range:

Grades 3

Time:

2 hours total or two 50 minutes

Purpose:

Address core social studies standards by teaching students the difference between windmills and wind turbines. This lesson will compare historical uses and modern advances in engineering to capture wind energy. It will look at maps to determine wind energy potential.

Materials:

Suggested Companion Resources (books and websites)

Vocabulary (with definitions)

  • Windmill: a machine that uses blades to convert the energy of wind into rotational energy (energy that moves in a circle)
  • Wind turbine: a device that converts the wind's kinetic energy (energy from movement) into electrical energy.
  • Electricity: Using electrical power to energize equipment
  • Wind speed: a measure of how fast the wind blows, usually measured in MPH
  • Wind capacity: a measure of wind energy potential
  • MPH (miles per hour): a measure of speed, how many hours an object could travel in one hour

Background – Agricultural Connections (what would a teacher need to know to be able to teach this content)

Centuries ago, windmills usually were used to mill grain (gristmills), pump water (windpumps), or both. Before the advent of modern machinery, windmills provided the power to turn large stones that were then used in grinding grain. This mechanical power turned wheat, barley, corn, and other grains into types of flour that could then be used to bake bread or in other types of cooking.

Historically in agriculture and in dry areas of the world, windmills were attached to a well and used to pump underground water up to the surface for the purposes of irrigation and to provide livestock with fresh, drinkable water. In wetter places like in the Netherlands, wind mills were used to pump water away so that they could drain land and use if for farming or other purposes.

These types of historical windmills harness the power of the wind and convert it into mechanical energy to do work (grinding grain and/or carrying water). Modern wind turbines harness the power of the wind and turn it into electricity using an electromagnetic generator. Inside the turbine there is a generator. As the wind turns the blades, the blades carry a magnet around a coil of copper wires. The positive end of the magnet pulls the negatively charged electrons through the wire. This movement and flow of electrons is electricity. The electricity is carried through transmission lines, through transformers, and ultimately to residential and commercial end users.

Windmills for torque power: The main difference in design is that turbines producing electricity need to spin fast so have fewer (typically three), thinner blades. Those that harness wind power to drive machinery, such as water pumps and windmills, need a higher torque and to be more stable. They generally have a higher number of larger blades.

Interest Approach or Motivator

Show a picture of a wind turbine and a windmill. Create a Venn diagram on a large writing surface (draw two side-by-side circles, overlapping in the middle). Label one circle ‘Windmill’. Label the other circle ‘Wind Turbine’. Have students compare the two pictures. Write their observations in the appropriate circle. Any similarities that the two pictures have in common should go in the overlapping section of the circles.

Possible answers:

Wind Mill                                                 Similarities                            Wind Turbine

Many blades                                             Tall                                         Few blades

Used to pump water                                 Both made of metal               Used to produce electricity

Used to grind grain                                   Reliant on wind to work         Modern (1983 in Iowa)

Used mostly by farmers in the past                                                                          

windmillwind turbine

Windmill: https://pixabay.com/en/windmill-farm-wind-water-2278930/

Wind turbine: http://ecolo.org/documents/documents_in_english/WindmillFormula.htm

Why do we need to generate electricity? Do we still need to grind grain and pump water? (Yes, but now we use electricity to do those things and so much more!)

Wind is a natural resource that we use to produce electricity which is similar to other goods and services that come from agriculture.

Procedures

Students will explore how wind mills can be used to do work and convert wind energy to mechanical energy.

  1. Part of what students are doing in this activity is reverse engineering, in which students look at something that exists to figure out how it works rather than building from the ground up. On the Windmill Template, the solid lines indicate where to cut the paper and the dotted lines indicate where to fold (but not crease) it. The circles indicate where to punch holes. The corners of the windmill are folded over and attached to the straw and the rubber bands are used to keep the windmill in place. On the worksheet, Figure C shows the cup and string attachment, and Figure D shows how to hold the machine so that the straw spins freely as the windmill turns. Students will discover through trial and error how best to attach the string to the straw. Because there is no exact description of materials, student choices may vary. For example, one team may choose regular bond paper for the windmill while another may choose a card stock. This provides a good opportunity to discuss how different materials behave within the design and why. Students familiar with pinwheels will know that blowing on the windmill causes it to turn. Students may then use this information to help them understand how wheel-and-axle machines work. If students are not familiar with this type of simple machine, you may want to identify it at the activity's end.
    1. Machine Assembly Instructions OPTION 1:
      1. Using one of the templates provided, draw your pattern on a sheet of paper. Transfer all the pattern's lines and circles.
      2. Use a pencil or single hole punch to punch a hole through the center circle (you may need to fold the pattern in half to use the single hole punch). Then punch a hole in each corner circle.
      3. Cut along the solid lines, making sure not to cut the center hole.
      4. Insert a straw through the center hole.
      5. Fold each corner along the dotted line and insert the straw through each corner hole. Slide the windmill to the center of the straw.
      6. Wrap a rubber band around the straw on each side of the windmill to keep the windmill in place.
      7. Punch two holes on either side of a small paper cup. Thread one end of the string through both holes and tie it to the middle of the string. Tie the other end of the string to one end of the straw.
      8. Hold the straw with both hands as shown in the diagram of the template. Blow on the windmill or use a hair dryer. As the windmill turns, the straw rotates, winding the string and lifting the cup. For a good working design, you need to make sure that the windmill and straw move as a unit and that the string doesn’t slip as the straw rotates. NOTE: if holding it in your hands doesn’t work, you can straighten two paper clips and insert them into either end of the straw. This should provide free movement of the straw.
    2. Machine Assembly instructions OPTION 2:
      1. Instead of step-by-step instructions, you can present the scenario and let students be creative on how they solve the problem. Give students any of the supplies from the supply list.
      2. Set up the scenario by challenging students to make a windmill that can lift weights in a cup up into the air.
      3. Design a windmill that will generate enough torque (power) to raise a cup attached to a string. Students can experiment with the size and shape of the windmill blades.
      4. Design a foundation for their windmills (attached to a table would work best). When it is time to test, use the hair dryer fan to power the windmill. Hold the hair dryer 10 cm away set on high. How much weight can your windmill lift? Use pennies or gram weights to weigh down the cup. You can redesign your windmill twice, each time testing and hopefully increasing the amount of weight that can be lifted. With the final design, record how much weight was lifted.
      5. Example: https://iptv.pbslearningmedia.org/resource/phy03.sci.phys.matter.zmill/exploring-windmill-design/?#.Wl5qOainGUk
  2. Ask students to describe how the windmill worked and record their observations through writing and sketches. 
  3. Students may experiment by changing the size of the windmill, the type of paper used for the windmill, the diameter of the straw, or even substituting entirely new materials.
  4. Why is Iowa a good place for wind? Students will look at map evidence to explain why many wind companies are moving to Iowa and why more than a third of Iowa’s energy is produced from wind. After creating and testing the student windmills, bring them back together and refocus them by displaying a map on a large screen.
    1. Introduce students to the U.S. Potential Wind Capacity Map: https://windexchange.energy.gov/maps-data/326 The map looks at the whole United States. Can students find Iowa? What other states have similar potential for wind energy as Iowa? (Montana, North Dakota, Minnesota, Wisconsin, Wyoming, South Dakota, Nebraska, Colorado, Kansas, etc.)
    2. What do those states have in common? (large flat open areas across the Midwest. Wind picks up speed as it comes over and down off of the Rocky Mountains.).
    3. Introduce students to the U.S. Average Wind Speed Map: https://windexchange.energy.gov/maps-data/319 What are the wind speeds in Iowa? (6.0 to 9.0 MPH) According to the My Family’s Wind Farm book, what wind speed do turbines need to produce electricity? (at least 7 MPH) According to that, do you think Iowa has good wind energy potential?
  5. Have students read or re-read the book My Family’s Wind Farm . Ask students to write a letter to Callee and her family and tell her why (or why not) they think Iowa is a good place for wind turbines. Students should use what they learned from looking at the maps to support their reasoning. They can use illustrations or pictures to help explain their points.

Essential Files (maps, charts, pictures, or documents)

Did you know? (Ag facts)

  • Wind energy has been used on farms for hundreds of years to water livestock or grind grain. Machines powered by wind were called windmills. Today, wind turbines are used on farms to make electricity.
  • Wind turbines are around 328 feet tall. The Statue of Liberty is only 305 tall. Wind turbine blades are usually 116 feet long.
  • Wind typically needs to blow at least 7 miles per hour to turn the wind turbine blades and produce electricity.
  • Each wind turbine sits on a half-acre of land.

Extension Activities (how students can carry this beyond the classroom)

  • Do you live near a wind field? Have students encourage their parents to drive by this wind field to get a closer look.
  • Have students do an inventory of every appliance in their house that uses electricity. They can record the names of the devices in a journal.

Sources/Credits

Author(s)

Will Fett

Organization Affiliation

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  • T5.3-5.a. Describe how supply and demand impact the price of agricultural goods
  • T5.3-5.b. Discover that there are many jobs in agriculture
  • T5.3-5.c. Explain how agricultural events and inventions affect how Americans live today (e.g., Eli Whitney - cotton gin; Cyrus McCormick - reaper; Virtanen - silo; Pasteur - pasteurization; John Deere - moldboard plow)

Education Content Standards

  • Social Studies:
    • SS.3.11. Provide examples of historical and contemporary ways that societies have changed. (21st century skills)
    • SS.3.13. Identify how people use natural resources, human resources, and physical capital to produce goods and services.
    • SS.3.21. Use map evidence to explain how human settlements and movements relate to the locations and use of various regional landforms and natural resources.
    • SS.4.17. Create a geographic representation to illustrate how the natural resources in an area affect the decisions people make.
    • SS.4.25. Analyze the impact of technological changes in Iowa, across time and place.
  • Science:
    • 3-5- ETS1-1. Define a simple design problem reflecting a need or want that includes specified criteria for success and constraints on the materials, time or cost.
    • 3-5- ETS1-2. Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
    • 3-5- ETS1-3. Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

Common Core Connections

  • English Language Arts:
    • RI3.3. Employ the full range of research-based comprehension strategies, including making connections, determining importance, visualizing, making inferences, summarizing, and monitoring for comprehension.
    • RI3.7. Use information gained from illustrations (e.g., maps photographs, etc.) and the words in a text to demonstrate understanding of the text (e.g., where, when, why, and how key events occur).
    • RI.3.10. By the end of the year, read and comprehend informational text, including history/social studies, science, and technical texts at the high end of the grades 2-3 text complexi9ty band independently and proficiently. (RI 3.10)
    • W.3.2. Write informative/explanatory texts to examine a topic and convey ideas and information clearly.
    • W.3.4. With guidance and support from adults, produce writing in which the development and organization are appropriate to task and purpose.
    • W.3.8. Recall information from experiences or gather information from print and digital sources; take brief notes on sources and sort evidence into provided categories.

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