Lesson 3: Wind

Getting Started

In Lesson 2 you saw how heat from the Sun causes air to move. Warmer air rises and takes up more room (creating areas of low air pressure), while cooler air sinks and takes up less room (creating areas of higher air pressure). Wind is caused by air moving from areas of high pressure to areas of low pressure — so essentially, wind occurs whenever there are differences in temperature.

In today's lesson, you will find out how and why winds blow in predictable patterns around the globe. You will also build your own anemometer.

NOTE: You will fill in your weather journal for today during today's activities.

Stuff You Need

  • Eyewitness Weather by Brian Cosgrove (revised edition)
  • compass (kit)
  • drinking straws (kit)
  • fan* (Activity 2 - optional)
  • hole punch
  • marker
  • paper cups (kit)
  • push pin (kit)
  • scissors
  • stapler
  • stopwatch or smartphone

* - denotes an optional material that may or may not be needed

Ideas to Think About

  • How are wind speed and direction measured?
  • How do global wind patterns affect local weather?

Things to Know

  • Wind is caused by the way the Earth is unevenly heated by the Sun. Wind occurs when there is a difference in air temperatures.
  • Uneven heating creates six large air masses, or cells, of different temperatures across the globe. Between each of these air masses is a powerful river of wind called a jet stream.
  • An anemometer is an instrument that measures the speed of the wind.
  • Wind chill is a measurement of how cold the air feels due to wind in cold weather.

Skills

  • Discuss and determine how the following create predictable patterns of weather: wind direction and speed, convection currents. (S)
  • Investigate how wind affects temperature. (S)
  • Use appropriate instruments and tools to collect weather data. (S)

Introducing the Lesson

Today your child will learn about wind. Wind can affect sporting events, building projects, and battles both modern and historic. He will look at how wind speed and direction is measured and tracked.

Your child will fill in his weather journal in Activity 2 and Activity 3.
Reading and Questions
Materials: Eyewitness Weather by Brian Cosgrove (revised edition)
Read about wind on pages 42-43 in the book Eyewitness Weather by Brian Cosgrove.

The website weatherwizkids.com provides information about different types of wind. Scroll through the page at the following web link and read these sections: the jet stream, global wind patterns, trade winds, the doldrums, prevailing westerlies, and polar easterlies.

When you are finished reading, watch the following video to find out more about global wind patterns. Then answer these questions:
Web Link
Web Link

Questions
  1. What historical tools did people use to determine the direction of the wind?
    Answers may include weather vanes, flags or pennants, kites, and windsocks.
  2. What is the Coriolis Effect?
    It is the bending of winds that begin at the equator and move toward the poles. The winds don't move in a straight line because the Earth is spinning.
  3. What are jet streams?
    Jet streams are strong, fast-moving currents of air that form between the global convections cells in the Earth's atmosphere.
  4. What is the Beaufort wind scale?
    It is a scale developed by Sir Francis Beaufort in 1805. It is used to estimate wind speed based on the wind's observed effects on land and water.