Wind Turbine

From Wind Power to Electricity ... and more

… and more: The wind rattle klopotec- a rattle that scares birds away

Thanks to the klopotec, the winemakers of Styria in Austria scare the birds away. How does this klopotec work? 

3.1 Task:
Draw a sketch of a klopotec and explain it to a schoolfriend.

Sources:
Wikipedia: Klopotec
Youtube: Christian Gratzer; Klapotetz / Südsteiermark
Youtube: fjerkovsky; Klapotetz en Argentina

... and more: Big wind turbines with three blades and no wind vane 

Big wind turbines usually have three blades. Could you explain why? What would be the disadvantages of many blades, a pair number or just the one?
Why do you never see a wind vane on a power station? How are they adjusted without a wind vane?

3.2 Task:
Search an answer to this question and write your findings on an information sheet.

Sources:
Scientificamerican.com: Why do wind turbines have three narrow blades, but ceiling fans have five wide blades?
Indianapublicmedia.org: Why Do Wind Turbines Have Three Blades?
Centurionenergy.net: Types of Wind Turbines

... and more: Rotor, propeller or repeller (turbine)?  

Rotor, wind turbine, aircraft propeller, turbine... we often read these terms.
When do we exactly say rotor, propeller or turbine?

3.3 Task:
Search through the following links to explain these terms differences. Write a little explanation.

Sources:
Wikipedia: Propeller (aeronautics)
Wikipedia: Turbine