Observation

Several days prior to Wind Energy Week, take your students on a series of five-minute field trips. Just walk around the school campus. If possible, walk around at different times of the day, and have the students observe and record their observations. Ask the students to use the Beaufort Wind Scale handout to help them estimate the wind's strength. Another good way to have the students record their findings is by using a list of sense observations as follows:

Date of observation:
Time of day:
Location of observation:
I can see: ________________________________________
I can feel: ________________________________________
I can smell: ________________________________________
I can hear: ________________________________________
I can taste: ________________________________________
I can taste: ________________________________________

After a few mini-field trips, students should begin to recognize a pattern. Does the wind blow harder or softer in the morning? Does the wind blow from the same direction each day? Are there times when the wind doesn't seem to be blowing at all?

After they have had enough time to gather data, bring the class together to discuss what they've discovered. Chart any "wind trends" the class as a whole agrees upon.

Wind Energy is Actually a Form of Solar Energy

That's right, the sun's warming of the earth is essential to the creation of wind. Our atmosphere is made up of air, which is composed of different kinds of gases. The sun shines on our atmosphere all of the time, but it heats the surface of the Earth unevenly, so in some places it is warm while in other places it is cold.

As the air gets warmer, its particles spread out. This makes the air light, or less dense, so it rises. As air cools, it becomes heavier, or more dense, and it sinks. As warm air rises, air from cooler areas rushes in to take the place of the heated air, creating wind. This process, called convection, causes the air to move.

Wind varies by season and wind is affected by land topography as well. Have the class try to reason why.

Some reasons why:

During different seasons, the sun's warming ability changes due to the Earth's rotation around it. Thus, in the winter the Earth's temperature is much different than during the summer months. Land topography can change the wind's momentum in a variety of ways. For example: mountains often create a tunnel, forcing great amounts of wind through small passes (that is why mountain passes can be windy areas). Ocean coastlines also create a windy environment due to the cooler water and the warmer land during the day, and warmer water and cooler land at night. So, why does a hot air balloon rise?

Examples from everyday life:

• Hot air balloon: Air is heated by a gas flame below the balloon. The hot air rises into the balloon, filling it up, since the hot air inside is lighter, or less dense, than the cooler air outside the balloon. As the hot air rises, it carries the balloon upward. When the gas flame is turned down, the air inside the balloon cools and the balloon sinks back to the ground.
• Sea breeze and land breeze: Coastal winds blow landward during the day and seaward at night. On a sunny day, the sand warms very quickly. The warm air over the beach rises, and the cooler ocean air moves in to replace it, causing a sea breeze. At night, the opposite happens. A land breeze is generated by the relative differences in temperature due to the more rapid loss of heat from the land than from the sea. The sea is able to retain its heat better than the land. The air over the sea rises from the heat retained in the water, and the cooler air from the land moves in to replace it. This causes the wind to change direction. So, why does the wind blow from different directions?
• Can the students think of any other examples?

Discovery

Provide the students with the opportunity to explore this concept. Facilitate this process by providing appropriate materials for the students to explore.

What happens when:

• Air is heated under a lightweight object? Use the Windy Wind Serpent handout with your students.
• You drop small feathers or blow bubbles in different places around the room? Can you find places where feathers rise or fall? Is there wind there?
• You blow towards a candle flame, pieces of paper on a desk or at a notebook? Does your breath become the wind? Why do you think your breath can move some things and not others? Discuss the differences between a light breeze, a windy afternoon and a tornado.

Review

• Did the students describe the wind using their senses? What examples did they give?
• Did the students find any patterns in their observations?
• Given the information that warm air rises and cold air sinks, were the students able to suggest any other examples of wind movement?
• Would your class conclude that your area is a good choice for a wind project? Why? Remember, wind projects must be placed in areas that are considered to have continuous wind.