Currently research focused on the area of teaching Chemistry has sought strategies and tools to improve the students' learning process. The use of playfulness has been one of the resources widely used by researchers and teachers in the classroom. When choosing games as an evaluative tool, the teacher can find it easier to identify students' difficulties, in addition to relaxing the way students are evaluated. The objective of this study was to develop a didactic game with the purpose of teaching the content of "collective properties", justifying it by the lack of games and research aimed at teaching Physics-Chemistry of Solutions. After construction, the game was applied to two classes in the second year of high school, in two different schools. In order to evaluate the application of the game, semi-structured questionnaires were used, which contained questions about the students' opinion about the use of didactic resources, such as the educational game. Through the analysis of the questionnaires answered by the students, it can be verified that after using the game, there was progress in the constitution of their knowledge, in addition to confirming that they approved the use of this resource in the teaching of collective properties. From this research it can be concluded that games are a great choice to be used in classes, being valid as a didactic resource, as it stimulates, motivates students, increases concentration and promotes group discussions and interactions. Al elegir los juegos como herramienta de evaluación, el maestro puede encontrar más fácil identificar las dificultades de los estudiantes, además de relajar la forma en que los estudiantes son evaluados.
The use of pesticides has been intensified to meet market demand. Brazil is the largest sugar cane producers in the world and one of its forms of consumption is raw cane juice popularly known as garapa. There is no legislation in the country that addresses parameters for the determination of pesticides in the sugarcane juice, therefore the marketing of the drink does not follow any quality control. The objective of this research was to evaluate the use of the Liquid-Liquid Extraction with Low Temperature Partitioning (LLE-LTP) method in relation to the selectivity, applicability, and effect of the addition of sodium chloride to determine the pesticide carbofuran in sugarcane juice and subsequent analysis of real samples of sugarcane juice sold in the city of Itumbiara -GO. This method is simple and effective, consuming small amounts of solvents and has advantages over other extraction techniques, such as practicality and low consumption of sample and organic solvent. The percentage of carbofuran extraction by (LLE-LTP) was 96.94-102.68% with coefficients of variation below 2.0%. The addition of sodium chloride did not show a statistically significant change in the percentage of carbofuran extraction. Samples of the sugarcane juice acquired in the Itumbiara -GO, submitted to the optimized method did not present any carbofuran residues.
The pineapple is praised for its aroma, flavor, and nutritional value. Researches of food composition and bioactive substances gained more space in the academic environment due to a more current severe concern of maintaining a healthier lifestyle. The objective of this paper was to quantify the presence of total phenolic compounds and to evaluate the antioxidant activity in vitro in the peel and pulp of two pineapples varieties: the Abacaxi Pérola and Abacaxi Havaiano (Ananas comosus), cultivated and commercialized at the region of the Triângulo Mineiro and Southern of Goiás. This region was chosen due to its geographic proximity to the city of Itumbiara, and for being a region with an outstanding production of the subject two varieties. The content of total phenolic compounds was evaluated using the Folin-Ciocauteau method and the antioxidant activity was assessed using the free radical scavenging method (DPPH • - 2,2-diphenyl-1-picrilhidrazil). The tests showed values of 72.53 to 143.90 mg GAE / 100g for each sample, for the aqueous extract and from 62.04 to 165.47 mg GAE / 100g of sample, the highest values being found for the bark extracts. For the test carried out with DPPH, to check the antioxidant activity of aqueous and hydroethanolic extracts, significant consumption of the DPPH reagent was not observed. The reading was performed for 1 hour without the measured value undergoing substantial changes. Therefore further studies need to be carried out to elucidate the antioxidant activity in pineapples.
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