Crank Out a Windmill

Windmill Cranks

Title of Lesson: Wind Crank

Background: Windmills are designed to perform a range of jobs, including irrigation control, grain milling, and power generation. Watch and learn how moving air -- supplied by a hairdryer -- gets transformed into usable energy capable of doing work.

Grades: K-5

Learning Goals: Students will be able to do the following:

  • Create a working mechanical windmill
  • Learn about alternative mechanical energy
  • Use the scientific process to see how many coins they think they can lift from the ground

Materials:

  • Blow dryer or Fan
  • Card Stock Paper
  • Masking Tape
  • String
  • Paper Cups
  • Washer or some kind of paylow
  • Unsharpened Pencils
  • Thumb Tacks
  • Scissors 
  • Ruler

Vocabulary

  • Windmill: a building with sails or vanes that turn in the wind and generate power to grind grain into flour.
  • Mechanical Energy: Energy that results when an object is at motion or is at a position to have motion.

Lesson:

Introduction
Wind energy is one of the fastest growing forms of electric power generation. The search for pollution free, sustainable energy has promoted this industry worldwide. Additionally, tax incentives for new wind installations in the U.S. have resulted in substantial growth in the industry. This nation ranks first in the world for wind electricity generation. Wind energy accounts for approximately 1% of our electricity supply. Texas leads the U.S. for generating wind energy electric power. Pennsylvania is the leader in the eastern states.

The Department of Energy is examining the feasibility of using wind energy to generate 20% of the nation’s electricity by the year 2030. The outlook for increasing the number of wind power plants and wind power technology around the world looks imminent.

Wind Energy Basics
Wind is caused by the uneven heating of the earth’s surface. Simply, wind can be defined as “moving air.” The wind’s energy has been used to do work throughout history from moving sailboats to generating electricity. Simple windmills, used for hundreds of years, were the primary technology that led to the modern wind turbines of today. The moving blades on a windmill rotate as the wind blows, turning a shaft or rod that can pump or crush something. Windmills of long ago were made to pump water and grind grain into flour. Small windmills were used in the 1920’s to generate electricity in remote locations which did not have electric service.

Today wind is harnessed primarily to generate electricity. The tall towers and large rotating propellers of wind turbines are becoming common place. Modern wind turbines, which usually consist of two or three blades, turn according to wind speed. As the blades or wheels rotate, energy is transferred to a shaft or rod to make it spin. The spinning motion drives a generator to produce electricity. The electric power is transported to consumers by way of an electric grid. There are horizontal axis and vertical axis wind machines, the most common being the horizontal axis. Wind machines vary in size. The largest has blades longer than a football field and is 20 stories tall.  One this size has the capacity to generate electricity for 1,400 homes. Wind farms, consisting of several to dozens of wind mills, are placed at strategic locations to harvest wind power.

Environmental Impacts
Wind is a clean and renewable energy resource, which has no polluting emissions. The most common environmental concern with wind machines are the effect they have on bird populations. Birds (especially “birds of prey”) and bats are killed when they fly into the rotors. The statistics on the bird mortality rates vary. Better placement of wind power plants has reduced bird mortality rates in some areas. Other concerns of wind power include noise and aesthetic impacts.

Activity:

  1. Do you know what a windmill is? A windmill is a building with sails or vanes that turn in the wind and generate power to grind grain into flour. Windmills use mechanical energy; Objects have mechanical energy if they are in motion.
  2. Now that the kids have this basic information, tell them that they will be making a windmill without any instruction and that you can only help by telling them certain hints if needed.
  3. Using the materials provided, they are to build a windmill that can be used to pick up a paylow in the cup.  Do not tell them how they should construct their windmill. They should use what they already know about windmills to create one. They can look at a picture of a windmill if necessary.

    Hints that are allowed:
    Windmills need to have wings for air to catch on
    When their windmill is on the table, it has to be able to spin to create the energy.

     
  4. Kids should first test that their windmill turns freely on the table before the resort to attaching the string that will carry the cup.
  5. Have them guess how many pennies they will be able to carry with their windmill and on what speed (must use scientific method in journal).

    For example, I predict that we will be able to lift 10 pennies on a medium speed. Or, If I use a high wind speed, the number of pennies I will be able to lift will be a maximum of 30. You may have to explain the scientific method to some.
     
  6. Have them time how long it took them to crank their pennies if time permits. Which wind speed was faster (low, medium, high)?
  7. Ask them to tell you what was the most difficult part of this task.

What I learned/Assessment:

  1. How did your group create its windmill?
  2. Are there any changes you would make to your design?
  3. Could your windmill be used for something other than lifting?
  4. How do you think windmills operate with the wind in the outdoors?
  5. What problems do you think windmills solve?