Este trabalho apresenta um estudo sobre os princípios teóricos básicos envolvidos na energia eólica e sua conversão para energia elétrica. E realizada uma abordagem qualitativa e quantitativa sobre a energia eólica de forma a relacionar os conteúdos apresentados com diversos tópicos estudados em física clássica. A energia eólica representa uma área do conhecimento rica em conteúdos que podem ser usados diretamente no ensino de física, contribuindo para um ensino mais contextualizado e atraente ao estudante.

This work presents a study about the basic theoretical principals involved in the generation of electricity from wind energy. A quantitative and qualitative approach is performed to the wind energy in order to relate the presented contents with several topics studied in classic physics. Wind energy represents an area of knowledge which involves several issues that can be directly used in the physics teaching contributing to a more contextualized and attractive teaching for the student.

In Brazil, yerba mate is consumed after processing; however, in Chile and Uruguay, the consumers prefer the cured product, which acquires a yellow color. For that yerba-mate is stored for a period of six months to one year, which increases the cost of the final product for the overseas market. This study evaluated the effect of humidity and temperature in maturation chamber on the time required for the product to get this characteristic. The changes in the color, pH, moisture and water activity were evaluated during the time of storage in different conditions of temperature and humidity. Yerba-mate subjected to higher temperature and humidity showed nearest color of the product submitted to natural storage. The loss of green color was related to the reduction in pH and increase in the moisture of the samples. The higher humidity allowed the mate to reach conditions near to market requirements abroad in approximately 60 days of maturation.