Scielo RSS <![CDATA[Educación química]]> http://www.scielo.org.mx/rss.php?pid=0187-893X20100001&lang=es vol. 21 num. 1 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.mx/img/en/fbpelogp.gif http://www.scielo.org.mx <![CDATA[<b>La enseñanza de la química para la sociedad del siglo XXI, caracterizada por la incertidumbre</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100001&lng=es&nrm=iso&tlng=es Society, science and technology are modernizing with brisk changes, and for that reason we feel that education must be renewed. We start this essay by analyzing the years of finalizing 19th century and beginning of the 20th, comparing all of that revolutionary changes with today's. Related with that, it is true that science has adopted an uncertainty sign since the arrival of the Heisenberg's Principle and chaotic systems. We wonder how our students can face all of these changes and all uncertainty in their science courses. We focus on ten topics that will constitute a Decalogue of Paradigms for the future of Chemistry Education: 1) Chemistry at the frontier; 2) Analogies; 3) Uncertainty; 4) Inquiry; 5) Models and modeling; 6) Nature of science; 7) Competencies; 8) Risk; 9) Communication and Information Technologies, and 10) Affectivity. <![CDATA[<b>Evaluaciones en cursos universitarios de Química</b>: <b>¿qué competencias se promueven?</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100002&lng=es&nrm=iso&tlng=es This project consists in analyzing written assessments for university basic Chemistry courses, in order to establish the extent to which they promote the acquisition of competencies that are valued in University graduates from science and technology studies. Activities are classified into three different categories based on the skills required to complete them: 1) Memorizing information and calculation, 2) Management of theories and concepts, 3) Integrating conceptual, methodological and information management aspects. Results show that 77% of the activities fall under category 2, 23% under category 1 and there are no activities under category 3. <![CDATA[<b>Estudio de pertinencia social del Programa Educativo de Químico de la Universidad Autónoma del Estado de México</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100003&lng=es&nrm=iso&tlng=es The purpose of this study is to assess the external or social relevance of the educational program of Chemist of the Universidad Autónoma del Estado de México and identify the elements that allowed the program to be assessed in order to improve its degree of social relevance. The relationship between the expectations of the socio-economic context - mainly from the perspective of employers - and working performance of the graduates was well identified. We also took into account the view of experts (key informants) whose career has been relevant in the chemistry area, and the training curriculum offered and professional development valued by graduates of the program. The research was done with descriptive-quality, gathering information through interviews and questionnaires. <![CDATA[<b>Competencias profesionales</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100004&lng=es&nrm=iso&tlng=es In the education based on competences (EBC), these direct the sense of the learning. The person who learns does it from the premeditation of taking place or carrying out something, being involved with the intentions of the society. The competences are part and end product of the educational process. The pattern of professional competences establishes three levels: The basic competences, the generic ones and the specific or technical whose range of generality goes from the wide thing to the particular thing. The present article analyzes those concepts. <![CDATA[<b>Razones para "concentrarse" en las razones</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100005&lng=es&nrm=iso&tlng=es Uno de los temas fundamentales en química es el de concentración de las disoluciones, el cual requiere del manejo y comprensión de los conceptos de razón y proporción. Para identificar el nivel de comprensión de estos conceptos, diseñamos y aplicamos una colección de problemas, relacionados con el uso de las diferentes unidades de concentración, a una población de estudiantes de nivel superior, cuyos procedimientos de resolución y resultados analizamos. Observamos que los estudiantes tienen hábitos de resolución muy arraigados y que no les es posible adaptar y clasificar los procedimientos empleados para resolver problemas de mayor complejidad, no obstante ser de contexto cotidiano. Además de errores y omisiones, pudimos constatar que los conceptos fundamentales de razón y su inmediato, la proporción, representan dificultades y limitaciones para los estudiantes cuando se hallan fuera del nivel algorítmico.<hr/>Concentration of solutions is a fundamental subject in chemistry, which requires understanding and handling the ratio and proportion concepts. In order to identify the level of understanding these concepts, we designed and applied a collection of problems related to the use of different concentration units, to a population of first year chemical engineering students, whose procedures of resolution and results were analyzed. We observed that students have strongly rooted habits and that it is not possible that they adapt and classify their procedures to solve problems of greater complexity,despite being of daily context.In addition to errors and omissions, we could state that the fundamental concept of ratio and its immediate one, the proportion, represent difficulties and limitations for students when they are outside the algorithmic level. <![CDATA[<b>Interpretación submicroscópica de una propiedad física</b>: <b>¿un problema resuelto?</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100006&lng=es&nrm=iso&tlng=es The aim of the work in hand is to come to conclusions as to why students relate boiling points of substances, such as halogens, with their atomic properties. The fact that this mistake has been observed in many evaluations brought about the implementation of a specific test to find out whether the students know that the boiling point is a macroscopic property of an elemental substance as in this case and not an atomic property. As the energy associated with a physical change is generally much lower than the one related to chemical bond breaking, the test also included a question aimed at finding out if students are able to differentiate between physical and chemical properties. It is thought that this could be helpful for them to relate boiling points to strength of intermolecular forces, and therefore overcome one of the most common alternative conceptions associated with this subject. Finally, in view of the different interpretations of the word "chlorine", used on an equal basis for the atom, the molecule and the elemental substance, the test provided a way to detect whether students that have already studied the subject of chemical bonds, are able to relate experimental data, state of matter and atomicity of chlorine; that is, that they can relate submicroscopic and macroscopic states. The analysis of the obtained results allows the identification of difficulties the students are faced with in this subject and the interpretation of possible causes. <![CDATA[<b>Formas de expresar la composición química en el SI</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100007&lng=es&nrm=iso&tlng=es Due to wide range and complexity of materials and chemicals, several quantities are normally used to express the chemical composition of mixtures.Nevertheless,during years those quantities have been reviewed in the frame of the International System of Units (SI) by international organizations related to chemical sciences and a set of quantities with unified nomenclature and notation has been proposed to express chemical composition. Important concepts related to chemical measurements like uncertainty and traceability are discussed to aim correct use and understanding of quantities and units of composition. A brief description of SI units and writing rules are also included. <![CDATA[<b>De la enseñanza disciplinaria a la formación interdisciplinaria de la ciudadanía en la enseñanza de las ciencias</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100008&lng=es&nrm=iso&tlng=es Este artículo marca los problemas de las características disciplinarias de la enseñanza de la ciencia desarrollada en el último grado de la enseñanza primaria brasileña, que se oponen a la dirección propuesta en los documentos oficiales o por las investigaciones académicas. Para mostrar una alternativa posible a esta situación se presenta una propuesta de enseñanza basada en la importancia de la interdisciplinariedad y de la contextualización en la educación básica para la formación de la ciudadanía. Se sugieren algunos puntos a ser considerados para la promoción de la Alfabetización Científica y Tecnológica de los estudiantes, utilizando como ejemplo el abordaje del tema 'Mar'.<hr/>This article presents the characteristics of disciplinary Science Education developed in the last grade of elementary Brazilian school that oppose the proposed direction by the official documents and academic research. To show a possible alternative to this, it is presented a proposal for education based on the importance of interdisciplinarity and contextualization in basic education for the training of citizenship. Some points to be considered in the school program of science for the promotion of Scientific and Technologic Literacy of students are suggested, using as example the approach of the theme Sea. <![CDATA[<b>La historia de la catálisis</b>: <b>Desde sus principios hasta los premios Nobel</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100009&lng=es&nrm=iso&tlng=es Although the effects of catalysis are known from very ancient times, the understanding of the phenomena started only in the 18th century and in due course led to the awarding to two Nobel prizes at the beginning of the 20th century.<hr/>Aun cuando los efectos de la catálisis son conocidos desde la antigüedad, la comprensión del fenómeno comenzó sólo en el siglo XVIII y con el tiempo culminó con la adjudicación de dos Premios Nobel en el siglo XX. <![CDATA[<b>Ultramicrovaloración potenciométrica de sulfato ferroso amoniacal con tres diferentes oxidantes</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100010&lng=es&nrm=iso&tlng=es A potentiometric Ultramicrotitration (titration of 0.2 mL) of ammoniacal ferrous sulfate with three different oxidants (potassium dichromate, potassium permanganate and ceric sulfate) was compared to the conventional potentiometric titration of the above reagent.This article compares the Ultramicrotitration against the conventional one, uses less than 2% of the reagents, consequently decreasing costs and waste in similar proportions. The optimization of resources, expenses and waste motivates an "ecological conscience" in both instructors and students that may also positively impact current industry standards. <![CDATA[<b>El bingo como recurso didáctico en el aula de secundaria</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100011&lng=es&nrm=iso&tlng=es A new educational proposal of a bingo game that presents to secondary school students (age 12 to 16) the chemical elements of the Periodic Table along with their properties is presented in this paper in an enjoyable way. Unlike other modalities proposed in the literature (Tejada and Palacios 1995; Franco-Mariscal 2006), this new version of educational bingo uses the periodic table itself as bingo cards and a computer application that picks out the balls. This educational game has been checked through some observations made by the teacher in the class and with an test of evaluation that was made before and later of the activity.The results show that students improve the learning of the contents related with the Periodic Table, besides to produce motivation in them. <![CDATA[<b>La hipótesis de Medea</b>: <b>¿La vida en la Tierra es a fin de cuentas autodestructiva?</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100012&lng=es&nrm=iso&tlng=es A new educational proposal of a bingo game that presents to secondary school students (age 12 to 16) the chemical elements of the Periodic Table along with their properties is presented in this paper in an enjoyable way. Unlike other modalities proposed in the literature (Tejada and Palacios 1995; Franco-Mariscal 2006), this new version of educational bingo uses the periodic table itself as bingo cards and a computer application that picks out the balls. This educational game has been checked through some observations made by the teacher in the class and with an test of evaluation that was made before and later of the activity.The results show that students improve the learning of the contents related with the Periodic Table, besides to produce motivation in them. <![CDATA[<b>Climántica</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100013&lng=es&nrm=iso&tlng=es A new educational proposal of a bingo game that presents to secondary school students (age 12 to 16) the chemical elements of the Periodic Table along with their properties is presented in this paper in an enjoyable way. Unlike other modalities proposed in the literature (Tejada and Palacios 1995; Franco-Mariscal 2006), this new version of educational bingo uses the periodic table itself as bingo cards and a computer application that picks out the balls. This educational game has been checked through some observations made by the teacher in the class and with an test of evaluation that was made before and later of the activity.The results show that students improve the learning of the contents related with the Periodic Table, besides to produce motivation in them. <![CDATA[<b>El ribosoma</b>: <b>lo que nos ha enseñado su estructura</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100014&lng=es&nrm=iso&tlng=es Hace 150 años se publicó la teoría de Darwin sobre la evolución que dice: "Las características de un organismo son hereditarias y sujetas a cambios al azar; los cambios que permiten al organismo mejorar sus opciones de supervivencia, se conservarán en las futuras generaciones". El Premio Nobel en Química 2009 fue otorgado a tres científicos que aportaron la última pieza requerida para conocer cómo funciona en realidad la teoría de Darwin a nivel atómico. El primer premio Nobel en este sentido fue uno de los más famosos en la historia: el otorgado en 1962 a Francis Crick, James Watson y Maurice Wilkins por el modelo atómico de la doble hélice de ADN. El segundo fue el otorgado en el 2006 a Roger Kornberg por la estructura de la ARN polimerasa que copia la información de ADN a ARN. El tercero, otorgado este año a Ada Yonath, Thomas Steitz y Venkatraman Ramakrishnan por la estructura cristalina de alta resolución del ribosoma - una de las maquinarias celulares más complejas - que completa el camino de la información genética, permitiéndonos conocer cómo el lenguaje de ADN/ARN se convierte en proteínas que garantizan el correcto funcionamiento celular. En los años sesenta se sucedieron varios descubrimientos clave para determinar que la información genética codificada a nivel de ADN es primero copiada a ARN mensajero (ARNm) y luego exportada fuera del núcleo. En el citoplasma, los ribosomas y los ARN de transferencia (ARNt) decodifican la información a secuencia de aminoácidos formando una proteína. El código genético fue completamente elucidado y sólo restaba conocer cómo funcionan a nivel químico estas moléculas para garantizar un proceso tan asombrosamente preciso, rápido y eficiente que además se ha conservado desde las bacterias hasta los humanos.<hr/>The Darwin evolution theory published 150 years ago stated:"All organism features are hereditary and subject to random changes; those changes allowing a greater chance for the organism to survive will be carried out in further generations". The 2009 Nobel Prize in Chemistry was awarded to three scientists for their contribution with the third piece of evidence showing how actually the Darwin theory functions at the atomic level. The first piece contributed in the same puzzle was one of the most famous Nobel prizes in history: the one awarded in 1962 to Francis Crick, James Watson y Maurice Wilkins for the atomic model of ADN double helix. The second one was the 2006 Nobel Prize awarded to Roger Kornberg for solving the structure of ARN polymerase and how it copies the information from ADN to ARN. The third one, awarded this year to Ada Yonath, Thomas Steitz and Venkatraman Ramakrishnan for the high resolution crystal structure of the ribosome - one of the most complex cellular machineries - completes the flux of genetic information, showing us how the language codified in ADN/ARN is converted to proteins that precisely control the correct cell functioning. <![CDATA[<b>No todos los extremos son malos</b>: <b>el caso de los telómeros</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0187-893X2010000100015&lng=es&nrm=iso&tlng=es The Nobel Prize in Physiology and Medicine was given to Elizabeth H. Blackburn, Carol W. Greider and Jack Szostak for their discovery of chromosomal telomeres and the mechanism by which the enzyme telomerase synthesizes and protects telomeres after each DNA replication cycle. This is a conserved mechanism in eukaryotic cells, which possess a true nucleus, and the length of telomeres and telomerase activity have important implications in ageing, degenerative diseases and cancer.