Wind turbines

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✍ Watch the first part of the video twice (“Deconstructed - part one.avi”). Fill in the blanks while and after listening. (one blank = one word)

“Wind turbine blades are _____________ designed to catch the maximum ________ of _______ ________ to make them rotate. Inside the turbine, an ____________ _______ transforms that _________ ___________ into electricity that is _______ in a ________. The stronger the wind, the faster the blades rotate, the more power generated. Getting the blades moving is the first step and to do that, of course, requires a _______ _______ _______.

The ________ ______ blades are aerodynamic to fully exploit ______ ______. One surface is rounded, the other relatively flat. Wind flowing over the ________ ____ speeds up and creates a ____ __________ pocket that sucks the blades sideways, what's known as ____. Now that lift sets the blades in ________, let's see how this rotation can be turned into wattage to power the fridge or stove.”

✍ Why are blades made in carbon fiber?[pic 19]

✍ Give an example of another system which uses lift process.[pic 20]

✍ Compare the wind turbine from video n°1 (Introduction) and the one from video n°2 (Deconstructed). [pic 21]

How electricity is generated? “Deconstructed part two”

✍ Watch the second part of the video twice (“Deconstructed - part two”). Fill in the blanks while and after listening. (one blank = one word)

“When the blades turn, they ____ a ______ connected to a _____ inside a generator. ________ small _______ fixed around the rotor turn inside the ______ made of coils of ________ _____. These magnets are an _____ of neodymium, _____ and boron. They are small but ___________. In fact, they're among the most powerful magnets on earth. The turbine needs their ___________ _________ to turn the blades' rotational energy into electricity.

When the magnets rotate inside the stator, they create a moving _________ _____ and the laws of ______________ dictate what follows : _________ in the ________ ____ also start moving. The movement of these electrons produces what's called an ___________ _____, the kind that comes out of conventional wall outlets.”

✍ What the function of the shaft?[pic 22]

✍ Explain how generator creates alternating current.

[pic 23]

[pic 24]

✍ At home, where can you found alternating current ?[pic 25]

How electricity is generated? “Deconstructed part three”

✍ Watch the third part of the video twice (“Deconstructed - part three”). Fill in the blanks while and after listening. (one blank = one word)

___________ ________ is easy to produce and _________ but impossible to ______ in a ________. It needs to be transformed into a ______ ________ in order to be __________. This _________ _______ inside the turbine does the job. With winds of _______ _____ miles ___ ______, this particular turbine can produce ____ _______ watts of power, enough to light up four one hundred watt light bulbs.

It doesn't seem like much. But the wattage can __ _________ by accumulating and _______ the energy in the battery.

✍ Give functions of these different parts of a personal wind turbine:

[pic 26][pic 27][pic 28]

CONCLUSION

✍ Look at the flash document named "How wind power works". From what you can see and understand, fill in the structural diagram below.

[pic 29]

[pic 30]