HELEN ARIAS , LEONTINA LAZO *, FRANCISCO CAÑAS
J. Chil. Chem. Soc., 59, Nº 4 (2014)EXPERIMENTAL ACTIVITIES IN THE LABORATORY OF ANALYTICAL CHEMISTRYUNDER AN INQUIRY APPROACHHELEN ARIAS1, LEONTINA LAZO1*, FRANCISCO CAÑAS2Intituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Curauma, Valparaíso, Chile.2Universidad Andres Bello, Departamento de Química, Facultad de Ciencias Exactas, Quillota 980 Viña del Mar, Chile.1ABSTRACTThis study analyzes the perception, development and improvement of the cognitive abilities of undergraduate students (of biochemistry and industrialchemistry) through the application of an inquiry methodology in the laboratory of analytical chemistry. The study was conducted during one semester. Theinstruments for data collection were a Test of Critical Thinking and a Questionnaire to determine the perception of the inquiry methodology and the traditionalmethodology, applied at the beginning and at the end of the semester. The results show an improvement in cognitive strategies and in the students’ perception ofthe inquiry methodology. This is consistent with future job performance.Keywords: Inquiry, laboratory activities, cognitive strategies.1. INTRODUCTIONProblem solving and laboratory activities are fundamental tasks inthe teaching and learning of science. Most teachers constantly use these asbasic tools for learning, infrequently calling into question their validity oreffectiveness or considering the critical nature of their formulation. Theobjectives of these activities are primarily focused on applying thinking skills:working techniques, data management, formulae and calculations, handlingof instruments and equipment, cleanliness and tidiness, plus the strengtheningconcepts through observation of phenomena. In addition there is the acquisitionof cognitive tools such as inference, generalization, abstraction, assumptionand research planning1The predominant instruction methods in university experimental activitiesconforms to the traditional style (also called expository, deductive or “recipetype”). This style relies exclusively on laboratory manuals to create a situationwhere the student performs the activity following a procedure established bythe teacher so as to achieve the objective in question. There is another nontraditional style (also called student-centered, inductive or investigative) inwhich the particular student plans and carries out the research needed to answera particular problem, enhancing the respective cognitive tools in a way thetraditional style does not1.The cognitive strategies of interest in this study are Critical Thinking andProblem Solving through the application of an Inquiry Methodology.Critical thinking is defined as reflective thinking that is focused on decidingwhat to believe or what to do 2-3.Firstly, critical thinking is a reflective activity. Its goal is often not tosolve a problem, but to better understand its nature. It is focused, sinceit involves thinking about something you want to understand better. Thepurpose of thinking critically is to evaluate information in a way that allowsus to make well-defined decisions4. Moreover, problem solving is defined asa cognitive process involving four steps5. The first is to locate the problem,then to clearly define it, and develop good solution strategies, it should thenbe evaluated based on the primary objective, and finally, the problem must berethought and redefined over time. Under this view, inquiry -based learningplaces emphasis on the resolution of authentic problems, i.e. those that occurin everyday life, in addition to allowing students to approach scientific inquiry.Scientific inquiry refers to the diverse ways in which scientists study the naturalworld and propose explanations based on evidence derived from their work. Italso refers to the activities of students in which they develop knowledge andunderstanding of scientific ideas, and of how scientists study the natural world.Some authors claim that the following skills are necessary to developscientific inquiry:a) Identify questions that can be answered through scientific investigation.b) Design and conduct a scientific investigation.c) Use appropriate tools and techniques for collecting, analyzing andinterpreting data.d) Develop descriptions, explanations, predictions and models based onevidence.e) Think critically and logically in order to relate the evidence and thee-mail: llazo@ucv.clexplanation.f) Recognize and analyze alternative explanations and predictions.g) Communicate scientific procedures and explanations.h) Use mathematics in all aspects of scientific inquiry 6-7.These skills can be promoted and developed in students in their learningspaces, such as experimental investigation-based activities, the most prominentlevels of which are the following: 1) confirmation experiments related tocognitive activities involving low-level tools, e.g. data collection guided by aprocedure; 2) structured inquiry in which the teacher asks a question based on aproblem and students seek answers through the implementation of a procedure;3) semi-structured or guided inquiry, where a problem is posed to students butthey must design the research in terms of a research question derived from theinitial problem; 4) finally, at the highest cognitive level we find open inquiry, inwhich students are allowed to raise their own issues and plan an investigationto obtain well-reasoned answers8-9.There are also significant issues concerning the capabilities ofexperimental activities within science learning. Some research shows that thereis little consensus regarding the utility of experimentation in the learning and/or reinforcement of concepts, the acquisition of skills, meaningful learning,extrapolation to daily life, etc. There are two main reasons for this: thestructuring of practical work (and reduced procedures due to time constraints),and a mismatch of the purposes of the teaching and the aims of the students. Forexample, one study compared the processes of thinking exhibited by studentsin a traditional setting with those exposed in investigatory environments. As thefirst is based on encouraging students to deduce, while the second encouragesthem to induce, differences are to be expected. Shepardson found that thethinking processes of laboratory students were focused on procedural tasks,while the thoughts of other students in the investigative environment focusedon data analysis and the search for the meaning of these results 10-15.The need for research arises from the finding that university studentsstudying subjects in the area of analytical chemistry in their professionaltraining generally show theoretical and practical deficiencies in relation tothese. This is also often reflected in their qualifications, and arrangement toconfront the laboratory work. It would appear that the students simply wantto finish the activity quickly, without making the most of the opportunity todeepen their reflection and questioning of their own learning. In this contextwe find the following research question: How can we improve and enhancethe cognitive strategies of students studying Analytical Chemistry in scientificdegree programs?The main objectives of this study is: to improve the skills in the developmentof scientific inquiry through semi-structured research methodology in thelaboratory of Analytical Chemistry; and to evaluate the impact on universitystudents in the application of a research methodology versus a traditionalmethodology in analytical chemistry laboratories.2. METHODOLOGYThe experimental design took the form of a field experiment, having theadvantage of greater generalization or transferability to educational situations2747
J. Chil. Chem. Soc., 59, Nº 4 (2014)as it is conducted in contexts that are real or very similar to these16. For thisresearch, we propose the following hypotheses: 1) The application of anInquiry Methodology in the Analytical Chemistry Laboratory enhances criticaland argumentative thinking in university students as well as the skills andabilities they need to tackle the problems associated with experimentation, thusbringing them closer to scientific inquiry, and 2) The investigative methodologyencourages students in the assessment of cognitive strategies developed duringproblem solving and through further experimentation, as opposed to theirperception of the classic laboratory activities. As the dependent variables arethe cognitive skills (inquiry and analysis) of the university students, while theindependent variable was the experimental work in the laboratory on the subjectof Analytical Chemistry. The variable is modified through the application of aresearch methodology using structured and semi-structured or guided inquiry.The structured inquiry approach was based on a research question(derived from a problem), to which the students gave answers by following aset procedure. Semi-structured inquiry was then employed, during which anyissues of interest to the students were raised, thus generating questions and thenaddressing one of them to seek answers through experimentation.The sample consisted of 64 students majoring in Biochemistry andIndustrial Chemistry who attended the course of Instrumental Analysis in thesixth semester in both curricula, which is part of an axis of 3 analytical chemistrycourses all involving weekly laboratory sessions. This course is the secondcourse of Analytical Chemistry for both degree programs, with the prerequisiteof two prior General Chemistry courses, a course on thermodynamics forBiochemistry, 2 Physical Chemistry courses for Industrial Chemistry and oneon General Analytical Chemistry, which covers the thermodynamic principlesof competitive steady-states in aqueous solution and its application for thedevelopment and control of volumetric and gravimetric methods.The practical activity is related to the content of the units on MolecularAbsorption Spectroscopy and Atomic Absorption Spectroscopy and is theculmination of a previous experimental learning axis, consisting partlyof traditional guided practices and semi-structured practices where thestudents develop technical skills for managing molecular and atomicabsorption spectrophotometers, the preparation of standards and calibrationcurves, quantifications in synthetic solutions, mixtures of analytes and errordetermination. All these sessions were distributed over 11 laboratory sessionsin 11 weeks:1.Molecular Absorption: Correct use of instrument, familiarizationwith pieces and parts. Drawing of external calibration curves and standardaddition.2.Molecular absorption (mixture analysis).3.Analysis of a sample (1): figures of merit, quantification limit,linear range, precision, accuracy.4.Analysis of a sample (1). quantification5.Flame atomic absorption. Correct use instrument familiarizationpieces and parts. Plotting a calibration curve.The students are given Sample Problem 2 which thy must analyze andunderstand from session 6 to session 11.Sessions 1 to 4 deal with molecularabsorption spectroscopy. The first 3 sessions will use structured practices todevelop technical skills in handling a molecular absorption spectrophotometer,its calibration, and the evaluation of analytical figures of merit. The thirdsession is the analysis of a sample synthetic problem, which is an iron solutionwherein the concentration of the analyte in solution is based on a structuredmolecular absorption method to determine the phenanthroline ligand.The fourth session is a semi-structured session where students mustdetermine Fe in a semi-synthetic test sample (e.g. a drug) using on themethodology developed in Session 3. The idea is for students to propose asolution treatment analyte and the dilution factors deemed most appropriate forquantification, keeping the instrumental conditions of Session 3.The fifth session is a structured session on the management photometer andatomic absorption spectrophotometers worked in both absorption and atomicemission modes. This session is focused primarily on familiarizing the studentswith the parts and components, the sensitive controls, optical alignment,preparation of basic standards and finally plotting calibration curves.After this the traditional axis begins, with open practice from session 6 tosession 11. To develop this axis, the students are given one of several analyticalproblems consisting of the determination of an analyte in a sample real problemfor which there is no validated methodology. Examples of these are:- Determination of Cu in agricultural soils.- Determination of Na in foods.- Determination of Pb in contaminated water.- Determination of K in human urine.For these analytical problems students must propose an entire analytical2748sequence corresponding to the collection and processing of the sample,instrument conditions such as analytical wavelength, concentration rangefor calibration of the mixture for the flame atomizer, system quantification,evaluation of analytical figures of merit (precision, accuracy, limit of detectionand quantification, linear range) and finally expression of the final result in awritten report. From proposal for the development of the analytical method toits implementation and validation, students have 6 experimental sessions in 6weeks. Each week students should also request a list of materials and reagents aweek in advance. During these sessions, in addition to assessing the final reportand the quality of the experimental procedure was also assessed in terms of theproper use of instruments, safety standards, washing equipment punctually, etc.The statistical basis for the development of these practices is based onIUPAC standards for the validation of analytical methods17. The physical basisof the techniques involved includes Beer’s law, the Boltzmann distributionand the laws of optics and electromagnetic radiation (absorption, emission,diffraction, dispersion), all known and reported in Instrumental AnalyticalChemistry texts18. Both the statistical basis and the physical principles of thespectroscopic techniques are reviewed in the respective lecture course whichwas developed in parallel to the experimental sessions. The experimentalactivities use guides designed from the investigation perspective, whereinitially a structured guide was used, in which students worked from a problemgiven that required empirical testing in order to be resolved. Subsequently,the students raised an issue of interest which could be addressed from theinvestigation perspective, posing questions, proposing hypotheses, designingprocedures, analyzing results and drawing conclusions.Data collection was conducted using the Critical Thinking Test to assesscognitive skills before and after the experimental investigation activities, anda Questionnaire was also used to obtain the students’ opinion regarding thismethodology and the traditional methods used in laboratories for AnalyticalChemistry.2.1. Critical Thinking TestThe version of the test used in this study was translated, adapted andvalidated in a thesis of education at the Southern University of Chile 19.This instrument was originally created by a committee of experts from theEducational Testing Service and the College Board in 1986 for the NewJersey Department of Higher Education’s College Outcome Evaluation Project(COEP). In this test the subject evaluates the information in two cognitivedimensions, Inquiry and Analysis.The inquiry dimension refers to the possibility of working or not workingto plan an information search (systematic procedures to construct, understandand extract ideas, classify and evaluate relevant material). The dimensionanalysis refers to the possibility that the person has to work or not work toformulate hypotheses, design strategies to break the information. This includesthe application of techniques, rules and models to solve problems, showspace, flexibility and creativity; assess conjectures, evidence reasoning, findrelationships and make conclusions19. These two dimensions were evaluated asfollows: 5 parts for inquiry (27 total points) and 2 parts for analysis (10 totalpoints), questions were associated with “climate El Niño”, with support frompictures and documents.2.2. Student Opinion QuestionnaireThe questionnaire used in this study aimed to gather the opinions ofstudents regarding the practical work with the research methodology and thetraditional methodology. The topics evaluated were: learning, problem solvingskills, group work and scientific research. In addition, two open questions wereadded in order that the students could express their pleasure or displeasureregarding the two respective modes.3. RESULTS AND ANALYSIS3.1 Critical ThinkingIn the Critical Thinking Test the average values of the scores associatedwith each dimension (Inquiry and Analysis), both pre and post-test werecalculated and the standard deviation and coefficient of variation were alsodetermined. The Dixon test or Q Test was applied20. This test was applied tothe initially dubious data, which were statistically accepted and considered insubsequent statistical calculations.With regard to the student opinion questionnaire for the quantitative andcomparative analysis, obtaining percentages for each topic evaluated, the mostrepresentative responses were chosen for transcription and qualitative analysisof the open questions.The results are presented along with the discussion of the assessment of the
J. Chil. Chem. Soc., 59, Nº 4 (2014)critical thinking of the students participating in the course, which is defined as the reflective thinking that is focused on deciding what to believe or what to do9.3.1.1. Analysis of the results of the pre and post-test.Table 1 presents the average score obtained by the students in the two dimensions assessed in the Critical Thinking Test both the pre-test and posttest.Table 1Average Score, percentage, standard deviation and percentage coefficient of variation for the pre & post-test.Average score PercentageDimensionStandard Deviation% Coefficient of 1412The initial profile of the students prior to the lab work can be defined asnormal in the scale of analysis, this includes the student’s ability to formulatehypotheses, design strategies to break down the information, as well as theapplication of techniques, rules and models to solve problems, show flexibilityand creativity, assess conjectures, evidence reasoning, draw conclusions andfind relationships 17. This profile is partly due to interventions by teachers, asstudents usually read and analyze scientific papers, bringing them closer to thehypotheses and research designs. All these cognitive skills must be developedin science degree programs, which are aimed at research and development areaswhich primarily can be achieved with the implementation of pilot activities atdifferent levels of depth.For the inquiry dimension, the results obtained by the students show alow average level. This dimension refers to the ability to be skillful or notto plan a search for information, including: building systematic procedures,understanding and extracting ideas, and classifying and evaluating relevantmaterial. This result is due to the use of traditional laboratory practices reflectedin the design of protocols for solving problems, failing to give students theopportunity to make changes and to achieve the expected and successful results.After completing the course, the Critical Thinking Test was applied,aiming to evaluate any improvement in cognitive skills; these results areshown in Table 1 as well as the parameters associated with the distributionof the results. After performing the investigative and laboratory experiments,the scores obtained can be used to qualitatively describe the student profiles,obtaining a standard classification in both dimensions, Analysis and Inquiry.From a qualitative p
J. Chil. Chem. Soc., 59, N 4 (2014) 2747 EXPERIMENTAL ACTIVITIES IN THE LABORATORY OF ANALYTICAL CHEMISTRY UNDER AN INQUIRY APPROACH HELEN ARIAS 1, LEONTINA LAZO1*, FRANCISCO CAÑAS2 1Intituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, Curauma, Valparaíso, Chile. 2Universidad Andres Bello, Departamento de Química, Facultad de .
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