Hands-on Activity Wild Wind!
Making Weather Vanes to Find Prevailing Winds

Learning Objectives

After this activity, students should be able to:

• Create a wind vane to measure wind direction.
• Gather and organize data about wind direction.
• Explain how engineers design technology to monitor, measure, and take advantage of wind energy.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Each group needs:

• scissors
• marker and pencil
• plastic soft drink bottle, smaller than 1-liter size (ask students to bring bottles to class the week before the activity)
• plastic drinking straw, not the bendable kind
• aluminum pie tin filled with small rocks, such as small landscaping rock
• white glue
• magnetic compass
• cellophane or masking tape, 3-4-inch strip

Each student needs:

• Wind Journal Page
• Wind Rose Diagram

Worksheets and Attachments

Introduction/Motivation

A weather vane or wind vane is the oldest tool used to predict weather. Throughout time, farmers typically placed wind vanes on their barn rooftops, often in the shapes of farm animals like roosters. Knowing the wind direction helped to inform farmers of incoming weather conditions.

Have you ever seen a weather vane? Where was it located? What did it look like? (Listen to student responses.) Weather vanes are usually found up high, on the tops of buildings so they can catch any existing breezes. Look for them on the rooftops of barns, garages, houses, schools, laboratories and weather stations.

How do wind vanes measure wind direction? Wind vanes work when an indicator, such as an arrow, reacts to wind gusts and spins on a rod to point in the direction of oncoming wind. So, if its arrow is pointing to the northwest, the wind is originating from the northwest.

The other end of the arrow is wide so it catches even small breezes. The breeze moves the arrow until it catches both sides of the wide end equally. The arrow always points into the wind, so you can easily identify the direction from which the wind is blowing.

Winds are caused by variation in air pressure and temperature. Local winds can change in minutes or hours. For example, sea breezes and land breezes near the ocean, change direction about every 12 hours. In most regions, however, the wind usually comes from one primary direction, called the prevailing wind. Prevailing winds are often influenced by global winds. Global winds move over the entire planet and do not vary much.

Wind vanes only measure local winds. However, the information we get from a wind vane can be used to infer the direction of prevailing winds in a region.

Engineers create tools that measure wind direction and speed. A wind vane is a simple instrument that can measure the direction of the wind nearest the ground where we live. Engineers design large weather balloons and other devices that gather wind direction and speed information as they float much higher above the earth's surface. They use all this data to design improved wind turbines to generate electricity, to figure out the best place to locate airport runways and wind farms, and to design computer models that predict and track weather and storms. Today, we are going to design a simple wind vane using limited materials to help us determine the direction of the wind outside, where we live.

Procedure

Before the Activity

• Have students bring in rinsed plastic soft drink bottles (less than 1-liter size) a week before conducting the activity.
• Make an example wind vane to show the class.
• (optional) Prepare overhead transparencies or photographs of different weather vanes to show students.
• (for younger students) Print the Block Arrow Template onto card stock or heavier paper (two per sheet), enough for one arrow per group. Students will cut out the arrows during the activity.
• Make copies of the Wind Journal Page and the Wind Rose Diagram , one each per student.

With the Students

1. Hand out the Wind Journal Pages. Read aloud the activity vocabulary terms. Have students list two terms under the "Vocabulary" column and define them. See if students have any questions about the definitions.
2. Discuss with students the difference between global winds, prevailing winds and local winds. (Answer: Global winds move over the entire planet, prevailing winds are those normally seen in a specific area or region of the Earth, and local winds are caused by local variation in temperature and pressure and local topography.)
3. Ask students: Where and when have you felt a lot of wind? (Possible answers: During a storm, on the beach, on top of a mountain, in an open area.)
4. Ask students: Remind me again, what are weather vanes used for? (Answer: They are used to measure wind direction, which informs us of incoming weather.)
5. Direct students to record on their journal pages any observations they have during the activity under the "What I've Observed" column. Explain that an observation is anything important that happened during the activity.
6. Show students your basic weather vane example. Let them know that their design must have a tab that fits inside of the straw and resemble an arrow shape to indicate the wind direction.  
7. Show students how a compass works. Remind them that the arrow always points north.
8. Divide the class into groups of four students each. Give them the weather vane materials.
9. Direct groups to write the four cardinal directions (north, south, east, west) on the sides of their plastic bottles. Have them use markers to label the bottle with the initials N on one side, S on the opposite side, E between N and S, and W on the opposite side. If it helps, draw this on the classroom board.
10. To the inside base of the empty pie tin, glue the bottom of the bottle. Set aside. 
11. Direct students to discuss in their teams what the ideal weather vane has. Encourage wild features, and emphasize that there are no bad ideas. Have them brainstorm together and sketch out their wind vane arrows. 
12. Have students cut out their arrows and decorate them if time permits.
13. Insert the bottom tab of the arrow inside one end of the straw, and gently tape the arrow tab to the straw (see Figure 1).

13. Place the straw into the bottle, making sure it is free to turn. It is best if the straw is longer than the bottle.
14. Place rocks around the bottom of the bottle in the pie tin to provide stability so that the bottle does not blow over during use.
15. Now students are ready to record wind direction data. Take the wind vanes outside and place them high in open areas, such as on a slide in a field or playground area. Have groups use their compasses to find north and align the wind vane N labels with real north.
16. Have students record the wind direction in the "What I've Observed" column of their journal pages. Make sure they realize that if the vane points to N, then the wind is blowing from the north (not from the south to the north).
17. Ask the students: "What worked with your wind vane? What did not? How could you improve it?" If time permits, allow the students to redesign their wind vane.
18. Back in the classroom, ask students: What do you know about prevailing winds? If it has not already been discussed, explain that prevailing wind is the direction that wind usually comes from, but does not always come from. Ask students: How can we determine the direction of the prevailing wind in our area? (Answer: By monitoring the wind over time and determining what direction the wind comes from most often.)
19. For the next two weeks, monitor the wind direction. (Note: If you do not have time to do this every day in class, have the teacher do it before class, or assign different students to record it daily at home or during the school day, or find the wind pattern information on the internet.)
20. After two weeks of wind data collection, have students analyze the data. Direct them to make data tables for the wind directions with one column labeled "Days" (with numbers corresponding to the days) and one column labeled "Wind Direction" (with the letter corresponding to the direction).
21. Have students count the number of days the wind direction was north, south, east and west.
22. By analyzing this data, have them conclude the direction from which the prevailing wind is coming, and write that in the observation section of their journal pages. Expect them to be able to infer that the prevailing wind direction is the direction that was measured most days.
23. Have students fill out the section in the journal page entitled "What I've Learned." Discuss with them what they have learned, and write their answers on the board. During the discussion, direct students to jot down any additional questions they might have under the "Questions I Have" column. Conclude by soliciting and discussing any remaining questions.

Vocabulary/Definitions

climate: Local conditions of a region including wind conditions and temperatures.

Coriolis effect: A global force that causes air to move in a circular motion because of the Earth's rotation.

global wind: The movement of air around the surface of the entire Earth.

land breeze: A breeze that blows from the land toward open water.

local wind: Wind caused by local variation in temperature and pressure and local topography.

prevailing wind: The winds normally seen in a specific area or region of the Earth.

sea breeze: A cool breeze blowing from the sea toward the land. It generally occurs in the early morning.

wind vane: A movable device attached to an elevated object for showing the direction of the wind.

Assessment

Pre-Activity Assessment

Journal: Hand out the Wind Journal Page. Read aloud the vocabulary terms and definitions. Have students list two terms under the "Vocabulary" column and define them. Ask for any questions about definitions.

Activity Embedded Assessment

Journal: Ask students to record any observations they have under the "What I've Observed" column. Observation are anything notable that happened during the activity.

Discussion Questions: During the course of the activity ask students the following questions to ascertain their progress.

• What are the differences between global winds, prevailing winds and local winds? (Answer: Global winds move over the entire planet, prevailing winds are the winds usually occurring in a region or area, and local winds are caused by local variation in temperature, pressure and topography.)
• At what locations and during what times have you felt a lot of wind? (Possible answers: During a storm, on the beach, on top of a mountain, in an open area.)
• Remind me again, what is wind vane used for? (Answer: It is used to measure wind direction.)

Post Activity Assessment

Journal: Have students fill out the sections in the journal page entitled "What I Learned." Discuss what they have learned, and write their answers on the classroom board. During the discussion, direct students to jot down any additional questions they have under the "Questions I Have" column. Conclude by soliciting and discussing any additional questions.

A Wind Rose: Have students use the Wind Rose Diagram to create a different kind of graph of the their collected two-week wind direction data. The attached wind rose diagram is an octagon with each side labeled like a compass: N, NE, E, SE, S, SW, W and NW. Each side has a rectangle protruding off it, split into several sections/bars. For each time the wind blew in a particular direction, color in a bar on that side of the octagon. Wind rose graphs are used by researchers and meteorologists to show at a glance the prevailing wind direction. If your school has a weather station that collects wind speed as well as wind direction, have students add that information to their wind rose graphs.

Investigating Questions

At activity end, ask students the following reflection questions to cement their understanding of the weather vane as an example solution to a simple design problem:

• If we look at weather vanes as an engineering design solution, then what is the engineering design problem they solve? How would you define the problem? (Answer: The challenge is to create something that helps us predict the weather. Knowing the wind direction helps to inform people, like farmers, of incoming weather conditions.)
• Another way to think of this is: What is the need or want? What is its purpose? (Answer: Design something to tell us the direction of wind.)
• When you created a weather vane in this activity, what was the most important thing that had to be able to do? What was its specific criteria for success? (Answer: The finished weather vane must be able to tell us from what direction the wind is blowing.) If it didn't do this job accurately or reliably, was it a success? (Answer: No)
• For the weather vane you made, what were the constraints? In other words, what were the conditions and materials that you had to work with? Perhaps a limitation on materials, time or cost? (Answer: We were given certain building materials and a time period to make it.)
• How is what you did in this activity similar to what engineers do? (Answer: Engineers create tools to measure wind direction and speed so that they can gather data from many locations around the world, which they used for many different purposes, such as track weather and storms and design other things like computer models to help meteorologists predict weather, wind turbines to generate electricity from the movement of the wind, and where to locate airport runways and wind farms.)
• How could you apply what you learned from your data—about prevailing winds in our location? (Possible answers: Where to locate house openings [doors and garage doors] so they are not at the windiest location, the most sheltered location to pitch a tent, how to orient outdoor animal shelters so they really provide protection from prevailing winds; where to store trash cans or other outside objects so they are least likely to be swept away by strong winds; noticing when the wind comes from a direction different than the prevailing wind as an indicator of weather conditions; where to locate an electricity-generating windmill on your property.)

Troubleshooting Tips

If the straw does not rotate, try using a longer straw or shorter bottle and check to make sure it is not catching on anything.

If the straw blows away, weight down the arrow with a little modeling clay to keep it stable.

If not enough wind, delay data collection to a windier period.

If you do not live in a windy area, find data on the internet.

Activity Extensions

Have students record the wind direction at different times of the day to observe how the wind changes. Also record how the wind feels. (Is it chilly or warm?)

Read aloud one of the literature books on wind listed in the References section. Discuss how wind can be given characterization: for example, cradle rocker, hat snatcher, child teaser. Brainstorm with students a list of characterization ideas for wind.

Have students look up the "Tower of the Winds," and describe the different gods or spirits on each side of the tower.

Have students explore ideas about wind and air by designing and testing a wind-detecting device in a variety of wind speeds at: https://www.fi.edu/science-recipes/wind-detectors

Activity Scaling

For younger students, provide the Block Arrow Template (see Attachment section) to help guide them. 

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation (GK-12 grant no. 0338326). However, these contents do not necessarily represent the policies of the DOE or NSF and you should not assume endorsement by the federal government.