Wind Energy 101
Focus: This lesson will provide a basic overview of wind energy and wind turbines.
Grade Level: 9th Grade to 12th Grade
Time: 50 minutes
1. Have students brainstorm a list of ways we can generate electricity.
List the ideas where students can see them. Then ask students to examine the
list and decide:
Which way do they think most of the power is generated in our area?
Which ways do they think are the most damaging to the environment (including
ecosystems etc)?
Which ways might be the least damaging?
Which ways could be considered renewable, or inexhaustible?
Which ways cost the most money?
2. Define “Renewable Energy” – Renewable Energy is energy which comes from
natural resources such as sunlight, wind, rain, tides, and geothermal heat, which
are renewable (naturally replenished). Tell the students that they will be
concentrating on only one renewable energy source today Wind Energy.
Ask students and let them give responses:
Question: What is wind?
Ans: Wind is simply air in motion.
Question: How do we know how fast the wind is blowing?
Ans: Anemometer. An anemometer is typically a small cup device that
measures wind speed, and is commonly found on the top of wind turbines to
gage wind speed. See one here:
Author: Jim Carlin
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Question: What causes wind?
Explain: Because the earth’s surface is made of very different types of land and
water, it absorbs the sun’s heat at different rates. This causes uneven heating of
the earth's surface which creates a difference in temperature between two
regions. A difference in temperature between two regions directly creates a
“difference in pressure” between them as well. This difference in pressure
actually causes the air to move (from high pressure to low pressure).
[So then, wind is simply air in motion as a result of a pressure difference
between two regions.]
An analogy to pressure difference can be shown using a clear tube with a
marble inside. When the ends of the tube are equal in height, the marble
does not roll. When one side of the tube is elevated, the marble rolls.
Each end of the tube represents a “pressure” P1 and P2. If the marble
rolls from P1 to P2, which is the higher pressure? (Ans: P1)
Wind Facts
Wind is affected by the rotation of the earth and causes it to flow in a
curved line. This is known as the Coriolus Effect.
The type of landscape can affect the wind. For example, heavily forested
areas or even city skyscrapers tend to slow wind down while open prairies
or water expanses allow for unobstructed faster wind speeds.
Wind speeds above the ground are higher than wind speeds near the
ground
3. Introduce the concept of Kinetic Energy – Kinetic Energy is the energy
something possesses due to its movement. Anything that moves has Kinetic
Energy, therefore wind has Kinetic Energy. This energy can be expressed in a
mathematical equation:
where “m” is the mass of something and “v” is the velocity
at which the something is traveling.
Mass has units of kilograms (kg) and velocity has units of meters per second
(m/s).
Author: Jim Carlin
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Question: What are the units for Kinetic Energy?
* Have students figure out what this would be using the above
mathematical equation.
Ans: kilograms meters squared per second squared (
) which is also
known as a Joule.
(Pronounced: “jewel”)
So,
= 1 Joule, and is about the amount of energy it takes to lift an
apple one meter off the ground.
Explain to students that Kinetic Energy can be applied to Wind Energy because
wind is moving. It is the Kinetic Energy of the wind that is converted by a wind
turbine, into Electrical Energy.
*Have students work the following exercise: (sketch on a board)
Let’s say that you have a block of air that is 1 cubic meter and has a mass of
1.18 kg. This block of air is traveling at 12 m/s. What is the Kinetic Energy of
the block of air in Joules?
Ans: ( .5 * 1.18 * 122) = 85 Joules
Now let’s say you have a block of air that is 100 cubic meters with a mass of
118.4 kg traveling at 12 m/s. What is its Kinetic Energy?
Ans: (.5 * 118.4 * 122) = 8524.8 Joules
Explain that this shows the difference in scale between the wind on a model
wind turbine (the size of a house fan) and the wind on a large wind turbine.
Author: Jim Carlin
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4. Describe to students the main components of a Horizontal Axis Wind Turbine
(HAWT):
[Sketch the following where students can see]
Tower – structural support of the wind turbine (around the length of a football
field high).
Blades – usually 3 blades each approximately 45 meters in length, capture the
wind energy.
Hub – rotating piece where blades are attached.
Low Speed Shaft – rotates at the same speed as the blades.
Gear Box – converts the low-speed-shaft rotation to a faster rotation shaft.
High Speed Shaft – turns the generator.
Generator – creates electricity.
Nacelle – houses the low/high speed shafts, gear box, and generator atop the
tower.
Author: Jim Carlin
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5. Show the following video which gives a brief overview of how a wind turbine
works. Before showing, make sure students are aware that they must answer
questions following the video: http://www.youtube.com/watch?v=tsZITSeQFR0.
Follow-Up Video Questions:
a.
b.
c.
d.
e.
f.
g.
Author: Jim Carlin
Where are some ideal places for a lot of wind?
How is wind speed measured on a wind turbine?
About how fast does the Low Speed Shaft turn?
How fast does the High Speed Shaft turn?
What is the Coriolus effect?
Why are wind turbines so tall?
A small wind farm can produce power for how many homes?
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