For hundreds of years, people have harnessed moving air (wind) to do work. The earliest forms of wind-powered machines were sailboats. Wind pushing against the sails of a boat provided the energy to move the boat across the water, saving people the trouble of rowing. Later, people discovered that if they attached sail-like panels to a wheel at the top of a stationary tower, wind blowing against the panels would cause the wheel and the central shaft to which it was attached to turn. The shaft drove mechanisms inside the tower that were used to mill, or grind, grain into flour. These wind-driven mills were called, simply, windmills. And even though wind-driven machines are now also used to pump water from wells and to generate electricity, the name windmill has stuck.
In this activity, students review the engineering design process and discuss how wind can be used to help get work done. They look at a variety of windmills, focusing on the different materials used in the construction of windmills and the type of work each windmill is designed to do. Finally, they use simple materials to build their own windmills to do work.
- Understand the engineering design process (define the challenge, brainstorm and research solutions, choose a solution that fits within constraints, design and build a solution, test the solution, evaluate and redesign if necessary)
- Recognize that moving air can be used to power machinery to do work
- Identify how windmills have changed as new technologies and materials became available
Grade Level: 3-5
- Three 50-minute blocks
- What Is the Design Process? QuickTime Video
- Air Is Matter Flash Image
- Exploring Windmill Design QuickTime Video
- Windmill Gallery Flash Image
- Windmill Worksheet (PDF) handout (PDF)
- Windmill Template (PDF) handout (PDF)
- sheets of plain paper, 8 1/2 in. x 11 in. (22 cm x 28 cm)
- sheets of construction paper, 8 1/2 in. x 11 in. (22 cm x 28 cm) (if students want to make different-colored windmills)
- pencils or a single hole punch"
- rubber bands
- paper cups
Before the Lesson
- Print out a copy of the Windmill Worksheet (PDF) for each student.
- Print out the two different-sized patterns (5" and 7") featured in the Windmill Template (PDF) for each student. If you wish, you or the students can scale this up to an even larger square-edged dimension.
Part I: Exploring Windmills
1. Tell students that they will use the engineering design process to explore windmills. Lead a discussion about windmills to find out what students already know. Ask:
- Have you ever seen a windmill?
- What did it look like?
- What do you think it was used for?
- How do you think windmills work?
Note that correct answers are not required here; you are simply looking for a base level of understanding to start the activity.
Define the Challenge
2. Ask students to describe how windmills do work. (They convert wind energy to mechanical energy.) Brainstorm together to come up with a good description (e.g., converting wind energy into work to help people).
3. Lead a conversation about the engineering design process to find out what students already know. Show the video What Is the Design Process? and review the description that the class came up with in step 2. Ask:
- What part of the design process did you complete when you came up with the description? (They defined the challenge: to design a machine that uses wind energy to do work.)
As students go through the various steps of the design process, you may want to record the steps in a chart. This will give students an overview of the process and where they are in it.
Brainstorm and Research the Challenge
4. Tell students that they are now starting the brainstorming and research component of the design process. Have them view the Air Is Matter still collage, and encourage them to discuss the types of things that air can do. Ask:
- How is air able to do these things? (Air has mass and takes up space, air exerts pressure, air moves.)
- Where in their lives have they seen air do work?
Part II: Designing Windmills
Brainstorming and Research
5. Start by reviewing the design challenge that students came up with in steps 2 and 3 [to design a machine (windmill) that uses energy from the wind to do work].
6. Next, show students the Exploring Windmill Design video. Ask:
- How is the engineering design process reflected in the video?
- Are there any changes you would make to this design? Why?
Design a Solution(s)
7. Windmills have changed dramatically since their invention. Have students review the Windmill Gallery still collage and look for the following design features:
- the tower (size, shape, materials used)
- the blades (size, shape, materials used)
8. Lead a discussion based on their observations.
Part III: Building Windmills
Build a Solution
9. Pass out to each student a copy of the Windmill Worksheet (PDF), the two different-sized patterns featured in the Windmill Template (PDF), and the materials needed to construct their own windmill. Let students choose the pattern size they want to use. Encourage the class to use a variety of sizes.
Test and Evaluate
10. After the windmills are complete, have students test them to see if they accomplish the work of lifting the cup. After several minutes, ask:
- What did you notice about the size of the windmill blades and how fast or slow the cup was lifted?
11. Lead a discussion about what design changes they would make if time allowed them to build another windmill. Ask:
- How would you improve your design? (make the windmill blades larger or use something stronger than a straw for the shaft, etc.)
Check for Understanding
Discuss the following:
- Show the students the Windmill Gallery still collage again. How are the windmills similar to and different from one another? How are windmills similar to fans? How are they different from fans?
- What design challenges did students face when building their own windmills? What constraints did they have to overcome? How might the design challenges be similar or different for a fan?