标题：An Active Learning-Based Integrated Project between High Schools and the University: Analysis of Bioethanol Fuel and Its Blends with Synthetic Gasoline
摘要：In order to increase the interest of high-school students in chemistry, and initiate their contact with the Institute of Chemistry of the University of São Paulo (Chem-USP), we introduced a project of socio-economic relevance, analysis of bioethanol fuel (hereafter called “ethanol”) and its blends with synthetic gasoline. We used concepts that these students are familiar with, and techniques that can be employed in high schools. Due to historical reasons, Brazilian students are familiar with the use of ethanol as fuel, either hydrous, or as a blend with gasoline in “flex-fuel” cars and motorcycles. They may lack, however, knowledge about industrial production of ethanol and possible adulteration of fuels. We carried out this project in three stages; I and III at the schools and II at Chem-USP. In stage I, the students conducted a literature survey, answered a quiz that their teachers corrected and discussed in class, and then prepared ethanol-water mixtures. In stage II, they came to Chem-USP to determine the densities and refractive indices of their aqueous ethanol mixtures, and the refractive indices of ethanol-synthetic gasoline mixtures using digital density meter and refractometer. They recorded the Uv-Vis spectra of the natural dye β-carotene dissolved in ethanol-water mixtures. All students constructed calibration curves (physical property versus mixture composition) and determined the composition of commercial unknowns (household cleaning ethanol and hydrous ethanol fuel). In stage III, the students discussed with their teachers the results of their experiments, and the concepts involved (e.g., hydrogen-bonding) and then answered an evaluation sheet of the project. They liked the active learning approach; their working in groups with modern equipment. The experimental part of this project can be carried out using less sophisticated infrastructure, namely, volumetric glassware, analytical balance, Abbe refractometer, and a low-cost spectrophotometer.
