Why is there wind?

Michigan 4-H is helping youth understand wind.

Wind graphic
This image shows how air masses can move causing the wind. Photo by NOAA SciJinks.

Have you ever wondered why is there wind? If your answer is yes, you are not alone. Many youth involved in Michigan State University Extension 4-H have also wondered why there is wind, especially in the fall season as they watch the colored leaves swirl around carried by this invisible force.

Wind is the result of the changing location of air masses. We all understand that we are surrounded by air, but it is not one huge blanket covering our planet. Rather, it is more like mosaic floor tile, existing in a variety of shapes and sizes but all impacted by the heat rays from the sun.

We’ve all felt the sun warm the air outside as the day progresses and as the sun moves more directly overhead. As the sun’s rays are absorbed by the ground, the ground becomes warmer and releases heat into the surrounding air mass. However, the ground does not heat evenly, so air masses move at different times and places. Think about the heat you feel when touching a dark car verses a light car on a sunny day. The dark car absorbs more of the sun’s rays so it will likely feel warmer to the touch. The same is true for the ground with its varying colors and surfaces.

As the air mass heats up, the air molecules gain energy and move faster, causing the air mass to spread out and rise. As one air mass rises, another air mass moves in to fill the space. Imagine scooping a bucket of water out of a swimming pool. Does the empty space remain? No, it is filled as the surrounding water moves in to fill the space. While we can see the water move, we can’t see the air mass move, but we can feel its movement as wind.

To help youth better understand why there is wind, ask questions like the following and encourage them to discover the answers:

  • Why is there usually less wind in the morning and evening?
  • Why is it almost always windy along the shores of the Great Lakes?
  • What evidence can you collect to discover how the air masses are moving?
  • What direction is the wind blowing now?
  • What does the direction of the wind tell you about the movement of air masses?

Additional resources to help youth explore wind:

  • Why Does Wind Blow? from NOAA SciJinks, It’s all about weather!
  • Wind Energy from the National Energy Education Development (NEED) project
  • WINDExchange from the Office of Energy Efficiency and Renewable Energy

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