... 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

Who is explore-it

a charitable association
The service agreements with the supporters of explore-it stipulate beginning with the project status that explore-it will become a provider of teaching and learning materials. It was not possible to provide materials and services for sale, being a research and development project of the Schools of Education. For this reason, the association was founded in cooperation with the partners of explore-it. The goal of the association is the promotion of technical understanding and natural sciences for children and youth. The association is exclusively non-profit and is tax-free since February 2010. The explore-it materials are assembled at the ARWO (sheltered workshop for persons with disabilities) in Wettingen in Argovia, Switzerland.

Foundation
To obtain advantage of donor funds and using them for specified purpose, the association created in august 2012 the "explore-it foundation". The aim is to promote understanding and innovation of children and adolescents in science and technology and to support and fund activities of the explore-it association.

a research and development project
explore-it goes back to a spin-off of the University of Teacher Education Valais (PHVS) and the PH of the University of Applied Sciences Northwestern Switzerland (PH FHNW) from 2008.

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