Anemometer

Description:
The anemometer measures wind speed.  A simple anemometer made with cups shows if the wind speed is fast or slow.  The electronic model can accurately show the speed of the wind in miles per hour or knots.  There is a free moving turbine suspended in the middle of the anemometer. This turbine, when held correctly, moves at the speed of the wind.  The speed of the turbine is sensed by an infrared light that relays the signal to an electrical circuit that digitally displays it.

Goal:
Students will be able to connect the accurate reading of an anemometer to the understanding that wind is the primary mover of weather.

Instructions for Set Up
The pocket anemometer must be used away from buildings or other tall structures.  The most accurate reading would be obtained in an open area.  The "on" slide must be moved to the desired scale, most often the miles per hour scale.  The unit must be held so that the wind comes through the back of the turbine. Using wind direction shown by trees or flags, direct the anemometer so that the wind enters the back of the unit from the direction the wind is blowing. In reading the display, the raised notch is a decimal point.  The unit uses 3 AAA batteries.

Anemometer
Activity:
The Wind Blows the Weather Around
Objective:  Students will be able to read the wind speed on the anemometer and relate that to changing weather patterns.

Materials:  Anemometer

Time:
1 hour whole group.
10 minutes each of the 4 following days
30 minutes for closure on the last of 5 days

Background Information:
 A layer of air surrounds the earth.  The sun shines through this air.  Some areas of the earth absorb the sunís energy.  Dark forest areas do this just like dark clothes absorb the sunís heat.  Icy areas reflect the sunís heat back into space and little heat remains in the surrounding air.  The differences between these warmer and cooler areas cause air to move at different speeds since heat causes molecules to move more quickly.  The oceans are fairly stable in temperature.  Land has many temperature changes.  All of these are factors in creating winds that move the air, the atmosphere, around the earth, creating weather. Wind moves from high to lower pressure areas.  The amount of air pressure is what creates wind speed or force. After a harsh and windy storm, there is often a day of wind.  The wind seems to clean out the storm.  The wind is moving in the direction of the low pressure system while calmer air is left in its wake.  Low pressure systems tend to bring windy, stormy weather.  High pressure systems tend to bring calm weather.

Procedure:
Introduce and discuss the origins of wind as the mover of weather from place to place.  Discuss low and high pressure systems in regard to wind.  Let the children know that the major wind forces on the earth are constant through history.  Early navigators to the New World, with ships full of horses, named the "horse latitudes."  This area has calm, warm weather and many horses would die there as the ships waited for wind to move them.  These conditions still exist there today.  There are many givens in wind and weather created by landforms, seas, and other factors already mentioned. Have the children list some of the "givens" that they know about wind and weather.
     Introduce the Beaufort Chart to the class.  In the early 1800ís, Sir Francis Beaufort, an admiral in the British navy, created a scale of wind force based on waves and shipís sails.  This scale is still used today as a common language for wind velocity.
    Introduce the actual anemometer to the class.  Demonstrate how it is used.  Explain the criteria for where it should be used outside and how it should be positioned.  As you take the class outside, ask half of the children to find a good location and the other half to find the direction of the wind based on the movement of trees and the school flag.  When the group has found the ideal location for gauging the wind speed, allow each child a chance to hold and read the instrument.  It takes approximately 4 seconds for the anemometer to display the wind speed after it has been positioned.
    When the children return to the room, have them begin the five-day wind journal. Each subsequent day have several children check the wind in the morning and in the afternoon.  Have then share their findings with the class.  The students will then write the speeds in their journals, noting any weather changes.  Watch for any wind events where there is a sudden calm or sudden high winds.  Have the children note these and predict the weather that is to follow.
    At the end of the five days, have the children reread their speeds and observations and share any thoughts they have regarding the wind and weather.
 

Wind Journal

Name  _______________
 

Day 1
Yesterdayís weather______________________________
Todayís weather_________________________________

Morning  mph   Beaufort force       Afternoon mph     Beaufort force
 

Observations  _________________________________________
 

Day 2
Todayís weather _______________________________

Morning  mph       Beaufort force       Afternoon  mph     Beaufort force
 

Observations__________________________________________
 

Day 3
Todayís weather _______________________________

Morning  mph        Beaufort force      Afternoon  mph     Beaufort force
 

Observations__________________________________________
 
 

Day 4
Todayís weather_______________________________

Morning mph        Beaufort force       Afternoon  mph    Beaufort force
 

Observations__________________________________________
 

Day 5
Todayís weather______________________________________

Morning   mph      Beaufort  force      Afternoon mph      Beaufort force
 

Observations_________________________________________
 

What I learned_______________________________________

___________________________________________________
 

The Beaufort Wind Scale
 
Force Speed mph Describe Effect
0 1 Calm Smoke straight up
1 3 Light breeze Smoke slightly bent
2 7 Light air Leaves rustle
3 11 Gentle breeze Leaves move
4 19 Moderatebreeze Small branches move
5 24 Fresh breeze Small trees sway
6 31 Strong breeze Large branches move
7 38 Moderate gale Whole trees move
8 46 Fresh gale Twigs break off
9 54  Strong Gale Roofs damged
10 63 Gale Trees uprooted
11 73 Storm Widespread damage
12 74+ Hurricane Widespread destruction

*The Nature Caompany Discoveries Library:  Weather.  David Ellyard, consulting editor.
 
 Barometer  Rain Gauge  Hygrometer  Probe Thermometer


This curiculum project was funded by the Colby Partnership for Science Education, the Howard Hughes Medical Institute, and the Bell AtlanticFoundation.