A CIESE Realtime Data Project

Lesson #2: Building and Using Weather Instruments

Overview

In this lesson students will build and learn how to use a set of weather instruments with which they will collect weather data over a period of two weeks.

Objectives

After completing this lesson, students will be able to:

  • Construct instruments for measuring weather.
  • Explain how each instrument is used to measure weather.
  • Demonstrate how each instrument is used to measure weather.

Materials

  • Directions and materials list for constructing each weather instrument
  • Commercial thermometers (one per group)
  • Commercial anemometer (for teacher use and demonstration)
  • Storage box for each group
  • Demonstration anemometer ( purchased from scientific supply company)
  • Compass
  • Paper plate or a large cardboard circle on which to mark compass points.
  • Stop watch or watch with second hand
  • Clay

Time: Approximately three hours spread over a one week period.

Teacher Preparation
The materials needed for the construction of the rain gauge, wind vane, and anemometer are listed on the Directions for Construction Page for each. Inexpensive outdoor thermometers can be purchased from school supply companies or may be brought in from home. Students should be divided into groups of three or four and work in these groups throughout the length of this unit. Since it would be impractical for the students to leave their instruments outside for the duration of the unit, each group will keep in a box its own thermometer, anemometer, wind vane, and rain gauge and take it outside with them each day. The thermometers should be purchased; the students will make the other weather instruments.

Directions for Construction:
Anemometer
Wind Vane
Rain Gauge

Note: The practice activities below are suggested to familiarize the students with the instruments. They can be completed on separate days or after they have constructed all of the instruments. They will not be making entries in their "official" weather log until Lesson#3.

Procedures

Activity #1 Introduction
For this activity, do the following:

Before you begin:

  1. Refer to the list (generated in Activity#3, Lesson #1) of weather attributes that they would like to study. Tell them that, although thermometer will be provided, they have the task of constructing the other instruments themselves
  2. Ask them some focus questions such as:
    • How can we tell from which direction the wind is blowing?
    • How can we tell how fast the wind is blowing?
    • What kind of container would be good for collecting rain?
    • How could rain be measured?
After a brief discussion, divide students into groups and have them brainstorm things or designs for things that they could use to measure wind, precipitation, and temperature. Gather groups together to report on their ideas. The groups will come up with different solutions to the problem that was posed (for example a group might decide to hold a long paper streamer straight up in the air and the direction that it points will tell them something about wind direction). After allowing time for reports, tell them that, although their ways are good and that they will have time to try out their ideas, you are going to show them how to make three instruments that they will be using in this unit. At this point, students may volunteer to bring outdoor thermometers from home.

Activity #2 Using A Thermometer
Temperature is measured with a thermometer usually made of a glass tube with colored alcohol. As the air gets hotter, the level of the liquid rises and, as the air gets cooler, the level falls. The temperature of the air is always changing. Air temperature is a very important part of weather measurement.
For this activity, do the following:

  1. Ask: Why is it better to use a thermometer for measuring temperatures rather than having people stand outside and tell whether it is hot or cold?
  2. Give each group a thermometer and let each student practice reading the indoor temperature. Students should look straight at the thermometer at eye level. If needed, review what each line between the larger numbers stands for.
  3. Go over the directions for using the thermometer outdoors:
  • After you go outside, wait two minutes before you take a reading. This is to allow the thermometer to get to outside air temperature.
  • Take outdoor reading away from the building.
  • Take the reading out of direct sunlight.
  • Hold the thermometer close to eye level; it should never be on the ground.
  • Do not allow rain or snow to fall on the thermometer.
  1. Students go outdoors and record temperatures.
  2. Check to make sure that they are reading the thermometers correctly.


Activity #3 Using a Wind Vane
A wind vane was probably one of the first weather instruments ever used. Knowing the direction of the wind is an important part of predicting weather because wind brings us our weather. The part of the vane that turns into the wind is usually shaped like an arrow. The other end is wide so that it catches the breeze. The arrow will point to the direction the wind is blowing from. If it is pointing to the east, it means the wind is coming from the east. Wind direction is where the wind is blowing from. Therefore a west wind is blowing from the west. To use a wind vane, you must know where north, south ,east, and west are.

For this activity, do the following:

Before you go outside:

  1. Check to make sure that there is some breeze.
  2. Make sure that the wind vanes are anchored in pieces of clay.
  3. Have the students mark north, south, east, and west on their paper plates.

When you go outside:

  1. Place the paper plate on a flat surface and put the wind vane on the plate.
  2. Use the compass to show the students where north is so that they can set up their plates facing the right direction. If you have access to a blacktop area, mark the compass points in chalk to make it easier for the students to read the wind direction.
  3. Students will observe the vane. If it is very breezy, one student should hold down the paper plate while another takes the direction reading. The arrow will point to the direction the wind is blowing from.
  4. Check the direction on the paper plate.

Activity #4 Using a Rain Gauge
Students can use tap water to practice reading the measurement of the rain gauge in the classroom. They will be taking measurements to the nearest 1/4" (5mm).

If there is a safe spot outside, the students can leave the gauge outside and take a reading after each rainfall, remembering to empty the jar after each reading. If the gauge can't be left outside, the students should place it outside on each rainy day. It should not be put it near or under trees or too close to buildings which may block the rain.

Activity #5 Using An Anemometer

Wind is the horizontal movement of air. The instrument that is used to measure wind speed is called an anemometer, an indicator that will spin in the wind. The anemometer rotates at the same speed as the wind. It gives a direct measure of the speed of the wind. Hold the anemometer in a place that has full access to the wind from all directions. Unlike the weather vane, it need not be pointed into the wind to spin.

An anemometer has four cups which catch the wind and cause the anemometer to spin. The inward curve of the cups receives most of the force of the wind. That's what makes the cups move. The more spins per minute, the greater the wind velocity. Using the average student-made anemometer, 10 turns per minute means the wind speed is about one mile per hour. Mount or hold the anemometer in a place that has full access to the wind from all directions.

Using the Beaufort Wind Scale, wind velocity is measured on a scale of 0-12, based on visual clues. Depending on the ability of students, it is probably sufficient that they recognize calm air, and gentle, moderate, and strong breezes.

Students can use a simplified scale such as the following:

  • Calm: Smoke goes straight up
  • Light: Wind is felt on face; weather vanes turn, leaves rustle
  • Moderate: Raises dust ; flags flap
  • Strong: Large branches move; umbrellas turn inside out

For this activity, do the following:

  1. Before you go outside: Mark one of the cups ; this will be the one they use for counting when the anemometer spins.
  2. Each group should appoint a time keeper who will be responsible for timing one minute for each trial.
  3. Each group should appoint an official "counter" for the day. The others may count on their own, but the counter's readings will be the ones recorded.
  4. Each group should appoint a holder who will hold the anemometer while the spins are counted; the holder should make sure that he holds the anemometer so that the wind is unobstructed.

When you are outside:

  1. Ask the students to describe the wind condition in words.
  2. Students set up their anemometers.
  3. They should make predictions as to how many times the anemometer will spin in one minute.
  4. When the time keeper says "Go" the counter in each group will count how many times the marked cup passes them in one minute and write it down.

Note: Depending on the ability of the students, if possible, the students should make four counts and record the average number of spins.

They can also multiply the average number of spins by 60 to find out how many times the anemometer would spin in an hour and come up with a statement such as: the speed of the wind today is about 1,000 spins per hour.

  • Ask: Can you make a statement connecting the number of spins of your anemometer and the speed of the wind?

At this time the teacher may choose to use the commercial anemometer. After the mph have been determined, the students can make a statement relating their findings to the actual wind velocity. For example: When our anemometer read 20 spins a minute, the commercial anemometer read 2 miles per hour.

Tell the students that they will be counting how many times their anemometer spins under different wind conditions.