Teaching Chemical Technique A Review of the Literature

Research: Science and Education

Teaching Chemical Technique A Review of the Literature Stephen DeMeo Department of Curriculum and Teaching, School of Education, Hunter College of the City University of New York, New York, NY 10021; [email protected]

Although the chemistry laboratory is used to provide students with opportunities to understand concepts, it has another fundamental purpose: to develop a student’s chemical technique. For more than a hundred years American chemistry teachers have been training their students to correctly weigh substances on balances, light Bunsen burners, transfer solids, pipet liquids, and titrate to a proper endpoint. For many of these years chemistry teachers have been basing a good percentage of the laboratory grade on technique as measured by a student’s accuracy and precision. The rationale for this pedagogy comes from an awareness that competent technique is in many cases essential to successfully and safely completing laboratory activities. The purpose of this study was to determine through a review of the literature some of the most effective ways to teach manipulative skills in chemistry. The value of this undertaking lies with teachers who are interested in solutions to how they may improve their students’ technique. The literature search was limited to the chemistry domain. Therefore, with the exception of a few studies, emphasis was placed on analyzing articles involving chemistry instructors and their students. I reviewed chemical education journals, laboratory manuals, early American chemistry textbooks, analytical chemistry texts, and science education textbooks and journals that have to do with instructional methods of teaching laboratory technique. Much of the early work is anecdotal and the authors do not rely on research to support their often prescriptive recommendations; work that is research based is described. The starting point of this review is Michael Faraday’s Chemical Manipulation, one of the first significant contributions to the chemical literature that underscored the pedagogical importance of teaching chemical technique. From here a variety of instructional methods and technologies that have been used in chemistry classes are discussed. This survey will ultimately result in the description of a trend toward more cognitive-based learning experiences for students trying to acquire manipulative skills in the laboratory. Faraday and Technique In 1827, Michael Faraday wrote a unique but necessary book entitled Chemical Manipulation. It was unique because it did not discuss mathematical equations, argue for new chemical laws, or try to interrelate experimental data and theoretical ideas. Instead the text described the physical requirements of a laboratory, various chemical apparatus and their uses, methods of performing chemical operations, the benefits of practice, and the reasons behind the success or failure of an experiment. That a great scientist like Faraday produced a non-theoretical text must have been a surprise to many scientists of the day. From the time of Greek science

the mind had always been superior to the hand; therefore, a theoretical treatise would be considered a greater contribution to chemical knowledge than a text devoted to chemical methods. So why did Faraday produce such a book? Being an extraordinary experimenter, Faraday attempted to adjust the level of the playing field between theory and method. No longer would method be seen as a lowly activity, a dirty and laborious enterprise that was often relegated to the responsibility of the technician or chemical savant. In the preface to the 656-page Chemical Manipulation (1, preface, p 7), Faraday wrote about the need for his book and discussed its special place in the chemical literature: The importance of instruction in manipulation has long been felt by the author during his professional experience as a public and private teacher of Chemistry in the Royal Institution; and the deficiency existing in the means of teaching it, induced him to think he might perform an acceptable service by putting together such information on the subject as there was reason to suppose would be generally useful to the student. No book contains those minute directions which are necessary in the present extensively cultivated state of the science, nor can verbal instruction teach that perfection of manipulation which is only to be gained by constant operation; but there is so much that can be taught, so much that can be suggested by such instruction, that is seems extraordinary that not one of the treatises upon Chemistry has been devoted to this subject, especially when it is considered that of the great numbers who now desire, or are assumed to have some knowledge of Chemistry, very few have access to competent practical sources. Lavoisier’s elements is the work which appears to the author to contain the best general directions, but every pupil to whom it has been shown, has found it to fall far short of his necessities.

Chemical Manipulation gained wide acceptance in Europe and the USA and resulted in three editions between 1827 and 1842. The popularity of the book was a clear sign that method was coming of age in chemistry. It highlighted the importance of accurate experimentation and helped to standardize methodologies that scientists and their students drew upon when working in the laboratory. Faraday intended his text to be used by educators as a “laboratory companion” to teach students procedural skills of chemistry. He planned for students to acquire these skills by reading and studying his text, viewing the diagrams, doing the experiments as he described them, and finally by practice. From the beginning to the end of Chemical Manipulation, Faraday stressed hands-on practice above the other pedagogical methods. He located the responsibility of mastering “ex-

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perimental knowledge” in two biological places: internally in the mind (“knowledge by study”, “reading this book”) and externally in the student’s hands. But it was the hand’s “constant operations”—their ability to perform repetitious manipulations—more than the mind’s activity that was critical for the mastery of a physical skill. By writing Chemical Manipulation, Faraday wanted to make experimental chemists; and by doing this he inferred that the central element in learning is experiential: an individual is not a predetermined being but can improve and learn new skills by following specific guidelines. A Variety of Pedagogical Methods Faraday was not alone. At the turn of the century in the United States, a similar cry for improved experimental ability was uttered by educators such as Smith and Hall, authors of a chemistry and physics textbook for teachers published in 1902 (2, p 111). One of the failings of chemistry teaching is the neglect of laboratory technique. The obvious value of neat and careful work, and of knowing how to adapt means to ends in mechanical matters, is so great, not only on account of its general educational value, but more especially because it is absolutely indispensable in really instructive chemical experimentation, that this neglect may well seem astonishing.

Like Faraday, these educators endorsed pedagogical techniques to improve students’ abilities to manipulate chemical instruments. One of the most prevalent techniques, which still exists today, is instruction through textbooks and lab manuals. Many authors claimed that reading clear and definite instructions will facilitate a students’ performance in the laboratory (2–6 ). Usually accompanying instructions are illustrations to help students visualize how to handle glassware and instruments (7–13). One author used humorous cartoon illustrations (14) to show proper technique; another recommended having students make their own drawing of lab equipment (15). In the research for his doctoral dissertation, Dechsri determined how a chemistry laboratory manual that integrated text and illustrations affected practical skill mastery. He found that students who used this manual gained significantly higher scores on measures of psychomotor skills than students who used a manual without pictures or diagrams (16 ). To instill a sense of seriousness in the lab, a text is often prefaced with an introduction or letter to the student describing the rigors of developing analytical skills and the consequences of poor technique. An example of this can be seen in an excerpt taken from an undergraduate analytical text (17, p 5): I would therefore advise every one desirous of becoming an analytical chemist to arm himself with a considerable share of patience, reminding him that it is not at one bound, but gradually, and step by step, that the student may hope to attain the necessary certainty in his work, the indispensable self-reliance which can alone be founded on one’s own results. However mechanical, protracted, and tedious the operations of quantitative analysis appear to be, the attainment of accuracy will amply compensate for the time and labor bestowed upon them.

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Within the philosophy of learning by doing, practice or repetition was by far the most popular instructional method that authors mentioned in the literature (18). Students are often instructed to carry out an experiment or manipulation multiple times to attain an acceptable level of physical skill. In some courses described in this Journal and in introductory chemistry lab manuals, students performed practice trials of new techniques before each laboratory activity (19, 20). In others the first laboratory activity was solely devoted to the development of techniques that students will use later in the course (8, 21–23). In an empirical study involving high school chemistry students, Grosmark found that students who performed one additional laboratory activity per week did statistically better on a laboratory skills test than a control group who was not exposed to the treatment (24 ). While most experiments found in lab manuals require students to routinely carry out procedural steps, one novel activity allowed students to empirically and rationally determine proper techniques. In this latter case, the authors of a student manual wrote (25): Some techniques are better than others, and in the procedures that follow you are to judge, on the basis of evidence and in the light of common sense and experience, which of the alternatives is the better or best technique.

For example, students are led through a series of comparisons choosing between lighting a Bunsen burner at the very top of the barrel versus lighting it a few inches above the barrel. In this way, they determined for themselves the better of the two techniques. Using an inquiry format to teach manipulative skills was empirically tested by Allison (26 ). This researcher found that introductory college chemistry students who were exposed to inquiry experiences in the laboratory had significantly better manipulative skills than students who were following structured, non-inquiry laboratory activities. Different modes of teaching chemical technique other than relying on printed materials and practice have also been used over the years. One common method has been called “elbow instruction”, or what is referred to today as feedback (2, 4, 27–29; also King, G. W. General Chemistry I Laboratory Manual; unpublished manuscript, 1989). Here the instructor observes students as they work in the lab and corrects any errors he or she sees. This technique has been described in various forms in the literature for more than a hundred years. Another pedagogical method prescribed by chemists has students begin with simple manipulations, which are followed by experiments involving more complex techniques (6, 20, 30–32). For example, in an organic chemistry laboratory course, the students must first “become familiar with procedures, understand them, and apply them when running more in-depth experiments” (33). Unfortunately, these descriptions of teaching methods (2, 4, 6, 20, 27–32, and King’s unpublished manual) were not supported by qualitative or statistical research. The use of evaluations is also seen to encourage careful work in the lab, especially when accuracy and precision are a significant portion of the lab grade. Goh, Toh, and Chia developed a program entitled “Modified Laboratory Instruction” to improve students’ manipulative, observational, and inferential skills (32). They believe that continual monitoring of students through formative assessments and

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teacher supervision can improve laboratory skills. In an article in this Journal, Plumsky argued that his unknown-based labs, which were evaluated immediately at the close of the laboratory period, promoted good laboratory practices. He wrote anecdotally about the change of his high school students’ behavior in the lab (34, p 453): My students crouch to read graduates and stretch to read burets. They engage in peer tutoring spontaneously, without my intervention. They scold each other for sloppy work. Most will take time to remove drops of water that adhere to the graduate above the measured water in Exercise 1, for example, and I’ve had students demand that I show them how to perform a eudiometer correction in Exercise 2, even though I’ve told them that a eudiometer correction probably wouldn’t affect their results in that lab. An indication of the degree to which students become involved in their work is that visitors—administrators, guidance counselors, student messengers—to my labs frequently complain that no one will point out to them the student they seek, so engrossed are people in their tasks. Good students are not considered nerds, nor is foolishness thought “cool”.

With a similar emphasis on assessment, Rondini and Feighan proposed an ongoing grading chart to show students their strengths and weaknesses in the laboratory (35). Using a posted chart with small coded letters that refer to the factors influencing a particular weekly grade, these educators have noticed an increase in student preparation and a “neater and more responsible approach” to experimental work. An older method that is popular in physical education classes but has seemed to attract little support in the chemical education literature involves a step-by-step imitation of the instructor by a class of students. In this situation, the instructor, positioned on a raised platform or rostrum, performs discrete actions that are carried out by students working with a parallel set of materials (36 ). The Pre-laboratory Experience Over the years, physical practice has been increasingly augmented with intellectual activities. This is mostly due to the rise of cognitive psychology and research on motor learning, which has found that learning a task by practice or repetition can be enhanced by thinking about or observing others perform the task (37). The most obvious shift in teaching manipulative skills in the laboratory was found in student chemistry manuals. It was increasingly common to have worksheets precede descriptions of experiments. These pre-laboratory assignments were thought to prepare students’ minds for learning new concepts as well as new physical skills. The thinking was: the more you know about a subject, the better you will do. This is not a radical shift in pedagogy. For years students have been, and still are, prepared mentally through prelab lectures, reading assignments, graded quizzes, and demonstrations. The shift on the continuum was gradual: educators slowly moved from the position endorsing the rule “practice makes perfect” to one that explicitly incorporated a mental component to learning lab skills.

The pre-laboratory demonstration has undergone some changes over the years. Since the 1970s, references to demonstrations recorded on video (slides, short movies, videotape and videodisc recordings, CD-ROM) began to appear in the literature (38–49). Research by Kemper and Palmer showed that videotaped demonstrations are as effective as written instructions in promoting technical skills (38). A follow-up study found that skills acquired by viewing a videotape could persist for a gap of up to 24 hours between viewing and performing the skill (42). Pantaleo showed that videotapes shorten in-lab instruction, prevent interruption of a laboratory session, and help students retain information about the lab (40). With regard to technique, 90% of the students using tapes met acceptable titration criteria, in contrast to only 73% of students not exposed to the tapes. It was also found that students using the prelab tapes had course averages 13 points higher on prelab quizzes than classes not exposed to tape instruction. Pantaleo attributes this success to the media’s ability to be replayed by the student, which is not possible with a live prelab lecture. One group of educators used videotapes with 200 introductory college chemistry students. The teaching assistants who taught the labs reported that student performance improved from the previous year, and responses to questionnaires indicated that students believed the tapes helped increase their understanding of the experiments (41). From his experience with videotaped demonstrations, Lightfoot estimates a 20% increase in student independence and motivation and a 10–20% decrease in time required for students to learn techniques (44). Lastly, a comparison between videotape and videodisc instruction in a freshman laboratory class showed that students who used the videodisc as a pre-laboratory activity achieved significantly better accuracy on an enthalpy experiment than videotape users (46 ). While the difference was significant, it should be noted that the two groups differed by only 2.4 points and the average score was in the 40th percentile range. The authors argue that the major benefit of using videodiscs rather than videotape is that students can select information based on their own needs. Among the videodiscs available is a recent HTML-based CD-ROM for Mac OS and Windows that prepares introductory chemistry students to work in the laboratory (49). It contains descriptions, photographs, graphics, animations, and voice narration to help students understand how to use lab equipment and follow common procedures. Audiotapes have been cited in the literature, but to a far lesser extent than video media. Audiotape has been used to present instructions on the use of instrumentation such as the analytical balance. One chemical educator reported that his tapes allowed “a class to pass through the introductory phase of balance instruction in significantly less time and with better technique than when instruction was by the standard method” (instructions given by the teacher) (50). For a lab course based on programmed independent study, Runquist developed kits containing a tape recorder, an audiotape, visuals, chemicals, and glassware (51). After listening to the tape and practicing the technique, students were required to complete a laboratory experiment that depended on the proper execution of the technique. If results were unacceptable the experiment was repeated. Runquist reported that he improved “student labo-


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ratory techniques from an estimated initial accuracy of ±5% relative error to less than 1% in basic techniques”, adding that students overwhelmingly approved of the teaching method, content, and rigor. Research on the use of computer-assisted learning (CAL) to improve lab skills has also been conducted. In an interactive simulation to determine the percent oxygen in a sample of potassium chlorate, Moor, Smith, and Avner had students assemble an experimental apparatus and then weigh samples, heat them to constant weight, cool them and weigh the residue, and make calculations (52). These authors used another CAL program to teach students how to weigh substances on an analytical balance. Students were shown a computer image of a balance and were taught the order of operations and which controls on the balance to use. An evaluation of this program indicated that students who did not use computers were twice as likely as those who participated in the CAL program to make an error in weighing. Similar results were found when the study was replicated the following semester. In four experiments in an organic chemistry course, Wiegers and Smith found that students using pre-laboratory CAL programs completed their 4-hour labs in 20–26 minutes less than a control group who did not use a computer learning program (53). Cavin and Lagowski found no significant differences in scores on a practical lab exam between a group of students who used a computer simulation of a spectrophotometer and a group who practiced with the instrument in the lab. They attributed this to the success of computer instruction in teaching students how to perform important procedural steps (54 ). Three other prelab activities reported in the literature are writing assignments, attention to errors, and cooperative learning. Pickering required students to enter the lab with a written summary of the experiment; no textbooks were allowed in the laboratory (55). He determined that students who summarized procedures in their own words spent significantly less time in the lab than those who used word-for-word copies of their manual’s procedure. In introductions to textbooks they have written, Horton recommended that students devise a specific lab plan (15) and Olsen recommended that they write an outline (56 ) before performing the laboratory activity. Other efforts by chemical educators to improve technique involve addressing common mistakes made in the laboratory (14, 15, 31). One such group of researchers concluded that two critical ingredients for promoting process skills are identifying the reasons why students make a mistake and following this by remedial help so that students avoid repeating the same mistake (32). An awareness of common lab errors was the impetus for a laser videodisc, Titration Techniques, published by JCE Software (47). The authors presented nearly 100 mistakes that can be used as prelab viewing assignments, in-class technique lessons, or evaluations. Shortly afterward some of these same authors introduced a 40-minute VHS videotape that demonstrates quantitative techniques in volumetric analysis (48). The tape, which addresses about ten techniques, includes “the quantitative transfer of a solid with a weighing spoon”, “a complete acid–base titration”, and “hand technique variations”. Lastly, cooperative learning has been used as a prelab pedagogical technique to increase students’ knowledge of lab procedures (22). Students work in groups discussing or 376

taking a quiz on procedural issues and how to prevent common mistakes made in the lab. The pre-laboratory experience was combined with postlaboratory teaching in a study involving 125 college students who were not majoring in the sciences (57 ). The purpose of the study was to determine the conditions that affect student achievement in the chemistry laboratory, one aspect being the learning of psychomotor skills. Students in a group exposed for an entire semester to a high ratio of indirect to direct teacher verbal behavior during pre- and post-laboratory sessions scored significantly higher on a psychomotor skills test than a group exposed to a lower or inconsistent ratio. Verbal behavior was defined as indirect when a teacher accepts feelings, praises or encourages, accepts or uses ideas of students, and asks questions. Verbal behavior is direct when a teacher lectures, gives directions, and criticizes or justifies authority. The psychomotor test involved six activities: (i) constructing a glass wash bottle, (ii) determining an object’s density, (iii) determining volume from an object’s measured mass and density, (iv) determining the percent by mass of potassium chlorate in an unknown mixture, (v) determining the normality of an unknown acid, and (vi) determining the rate of decomposition of aqueous sodium hypochlorite. The researcher concluded that achievement of psychomotor skills in the chemistry laboratory is affected by the professor’s pattern of verbal interaction, specifically by the ratio of indirect to direct verbal behavior. To date, there has been no research on how postlab teaching in the absence of prelab activities can affect the learning of manipulative skills. Combining Physical Practice with Mental Practice The pedagogical emphasis on mental preparation and how the mind can improve the acquisition of motor skills has continued to the present. One promising method cited in both the psychological and the chemical education literature is called mental practice (37, 58–60). Mental practice refers to a teaching method that requires the learner to mentally or introspectively rehearse the motor skill to be learned. Oxendine clarifies the difference between mental and physical practice (37, p 222): Actually, references to mental practice and physical practice are somewhat misleading since they seem to indicate that the individual functions at a purely physical or mental level. The truth is that in the physical performance of a task there is usually some degree of related mental activity, while in mental practice certain neural and muscular responses are evoked. In light of this, the concept of mental practice could perhaps be understood better if it was thought of as sedentary practice.

Other terms that refer to this method are conceptualization, ideational functioning, introspection, and imaginary practice (37). Mental practice was evaluated in chemistry classes by Beasley in the late 1970s (19, 60, 61). He randomly assigned 360 first-semester introductory chemistry students to four groups. Each group was taught by a different pedagogical technique as they determined the percentage chloride in an unknown chloride sample by volumetric titration. The first group used physical practice, the second group used mental practice, the third used a combination of physical and mental



practice, and the fourth used neither method, acting as a control. A sense of mental practice can be gleaned from an excerpt of the instructions Beasley gave his students (60, p 474): Review the whole sequence for that skill by slowly reading the statements describing each step and relate this to the associated illustration. As you concentrate on the description and the illustration of each step, imagine yourself performing these actions in the laboratory. Attempt to “feel” your way through each skill for a period not exceeding 5 minutes at any one time. Repeat this procedure at least once daily prior to your scheduled Experiment II laboratory session. Time permitting, review this sequence just prior to the start of Experiment II.

Beasley used the accuracy of students’ laboratory performance on a pretest and posttest to determine their level of proficiency. Results of the pretest showed that beginning college chemistry students were not proficient in volumetric analysis techniques on the completion of high school courses. Results of the posttest showed no statistically significant difference between treatment groups. The differences between the treatment groups and control suggest that some sort of planned practice would likely improve students’ manipulative skills. Beasley believes that mental practice can be incorporated readily and inexpensively into the syllabus through demonstrations, videos, and other pre-laboratory activities. However, although Beasley found that the group using mental practice alone was on a par with the other groups, researchers in biology found that students who were taught laboratory skills in a discussion setting had poorer technique than students who learned skills in a laboratory (62). Making an explicit connection between the rationale or purpose of a technique and how the technique is performed has been used in the context of mental practice. A study on students acquisition of process skills recommended “clear experimental procedures that provide students with the ‘why’ and ‘how’, vis-a-vis the cause-effect of a particular procedure” (32). Student conceptual knowledge of manipulative skills was viewed as important to other chemical educators (29, 63). In an introductory letter to chemistry students, one author of a laboratory manual supported the notion of practicing with purpose: “Be sure [of ] the meaning and purpose of all directions for each experiment before you perform it. Laboratory work should be thoughtful, not mechanical” (64). In the face of these many pedagogical efforts to raise the level of students’ laboratory technique, an article in this Journal questioned whether introductory college chemistry students actually need to improve their manipulative skills (65). A group of freshman biology students were given the task of determining the amount of fluoride in dental tablets by potentiometric titration. To help them, each student was given a brochure describing the theory, setup of the instrumentation, and procedural steps of the experiment. An evaluation of accuracy showed that students’ results had a relative standard deviation 3.5 times higher than that of reference experiments carried out by experienced personnel. However, the authors maintain that half of this error is due to a few bad experiments and they consider this level of error to be acceptable, especially since the students had no prior experience in an analytical laboratory. Based on the results of this small comparative study, the authors have directed their efforts not to improving

their students’ technical skills but to improving computational skills. Unfortunately, there was no pedagogical intervention and no measurement of students’ manipulative abilities before and after the intervention. Therefore, more research is needed to support these findings. Conclusion Over the years there have been a host of teaching methods to improve students’ technique in the chemistry laboratory. Many are intuitive approaches with no theoretical justification and some, like video instruction, are based on empirical studies of chemistry students. The different ways to teach laboratory technique mentioned in this article are collected below. Together they may be useful to teachers who are looking for alternative forms of instruction. reading textbooks and lab manuals writing clear and definite instructions creating illustrations letter to the student practice allowing students to determine the best technique observation and feedback moving from simple to more complex manipulations evaluate skills mirror procedural steps of instructor perform demonstrations giving prelab assignments (readings, quizzes, questions) create video images record audio tapes use computer-assisted learning summarize procedural steps address common mistakes cooperative learning mental practice connect “why” to “how”

While it may be difficult to choose the “best” method to improve students manipulative skills, it is clear from the chemical education literature that video can be useful to promote skill acquisition. Using videotapes, videodiscs, CD-ROMs, and most recently the Internet can have several advantages. For example, specific procedures that are difficult to demonstrate to a group can be shown with video close-ups, and with editing, extraneous images can easily be removed from sight. Because video media such as tapes can be readily copied, students can view techniques as many times as they wish and at a time and place convenient to them, such as at home or in their library. The review of the literature also strongly suggests that some sort of mental preparation combined with physical practice can benefit students’ laboratory skills. Mental preparation in the form of questions, summaries, or imaginary practice is cost effective and places minimal demands on the instructor. Using verbal behavior that encourages and is responsive to the student during these prelab sessions can be very effective in promoting psychomotor skills. Feedback seems to be another key component in mastering a skill. Although not validated extensively by empirical studies in chemical education, feed-


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back has been shown to improve the learning of procedural knowledge (66 ). The trend in teaching technique in the chemistry laboratory is to demand more work from students before the laboratory activity begins. In other words, there is a heavier accent on developing a prepared mind before the manipulation. Technique is not taught today as it was in Faraday’s time; the mental component to teaching technique has increased substantially. While this cognitive direction is supported by current research, it is important not to ignore the fact that students need time to practice the techniques they have learned. It is very doubtful that a student will gain mastery of a new technique made up of a complex set of procedures by practicing it only once or twice in the laboratory (63, 67 ). Another aspect of emphasizing mental preparation that one must guard against is cognitive overload (20). Students’ mental abilities can become strained when too much information is presented in a prelab setting. Discussions of technical skills, concepts, safety issues, observations, interpretation, and computational requirements at one sitting immediately before lab could be detrimental to learning. Research on teaching laboratory skills is lagging behind research in disciplines such as physical education and behavioral and cognitive psychology, which have investigated the teaching of procedural knowledge for many years. For example, in the late 1960s, Gágne showed that the successful acquisition of technical skills depends on the learners having a mental overview of the skill to be learned, being given feedback when they are doing the skill inappropriately, and being able to practice (66 ). Psychological research has shown that knowledge of results (as in feedback) is more important in promoting mastery of a skill than knowledge of the principles behind the skill (58). Motivation, such as desiring a reward for accomplishing a task, is also an important factor in acquiring mastery of skills (68). Some methods different from the ones listed above have also yielded positive results. Cognitive psychologists have found that spacing of practice increases learning, that there is frequently a positive transfer between related skills, and that a procedural skill can be learned better if it is broken down into independent parts that are learned separately (69). It has also been shown that the presence of an audience can disturb and interfere with a learner’s acquisition of a new task but can produce a slight improvement in performance if the task is already learned (58). New insights that may improve laboratory technique may very well come from cognitive psychology and the results of psychomotor studies. While educators could argue that learning manipulative skills is not as important as learning concepts, it is still important to address the question of how students can effectively acquire laboratory skills. Although this review centered on learning chemical manipulations, a larger concern involves how young science learners in elementary, middle, and high schools perform laboratory techniques in general. For example, Sterling has reported that U.S. students overall do not compare favorably with their counterparts in other countries in their ability to accurately measure scientific variables (70). These poor scores are a concern because the ability of students to make accurate measurements and to effectively use laboratory equipment are included in the new standards of science

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described in the Benchmarks for Science Literacy (71) as well as the National Science Education Standards (72). It is hoped that this review will be a timely response to the concern of these international assessments by making readers aware of some of the more successful approaches to teaching manipulative skills in the laboratory. Acknowledgment This research was funded by a PSC-29 grant from the City University of New York. Literature Cited 1. Faraday, M. Chemical Manipulation; Wiley: New York, 1827. 2. Smith, A.; Hall, E. H. The Teaching of Chemistry and Physics in the Secondary School; Longmans Green and Co.: New York, 1902. 3. Hinrichs, G. School Lab. Phys. Sci. 1871, 1, 65–70. 4. Scott, W. W. Qualitative Chemical Analysis: A Laboratory Guide; Van Nostrand: New York, 1918. 5. Willard, H. H. J. Chem. Educ. 1928, 5, 958–963. 6. DeWitt, C.; Rogers, L. B. J. Chem. Educ. 1946, 23, 169–173. 7. Francis, G. Chemical Experiments: Illustrating the Theory, Practice and Application of the Science of Chemistry; Daniels and Smith: Philadelphia, 1850. 8. McPherson, W.; Henderson, W. E. Laboratory Practice in Chemistry; Ginn: New York, 1922. 9. McGill, M. V.; Bradbury, G. M. Chemistry Guide and Laboratory Exercises; Lyons and Carnahan: New York, 1935. 10. Black, N. H. New Laboratory Experiments in Practical Chemistry; Macmillan: New York, 1936. 11. Brownlee, R. B.; Fuller, R. W.; Hancock, W. J.; Sohon, M. D.; Whitsif, J. E. New Laboratory Experiments in Chemistry; Allyn and Bacon: New York, 1947. 12. Baker, P. S.; Bradbury, G. M.; McGill, M. V.; Eichinger, J. W. Chemistry and You in the Laboratory; Lyons and Carnahan: Chicago, 1962. 13. Morgan, A. First Chemistry Book for Boys and Girls. Charles Scribner’s Sons: New York, 1962. 14. Wirth, H. E.; Burtt, B. P. J. Chem. Educ. 1945, 22, 501–502. 15. Horton, R. E. Laboratory Manual in Chemistry; D. C. Heath: New York, 1937. 16. Dechsri, P. The Effectiveness of a Chemistry Laboratory Manual Design Incorporating Visual Information Processing Characteristics on Student Learning and Attitudes. Ph.D. Thesis, University of Northern Colorado, Greeley: Dissert. Abstr. 1994, 55 (09B), 3849. Dechsri, P.; Jones, L. L.; Heikkinen, H. W. J. Res. Sci. Teach. 1997, 34, 891–904. 17. Fresenius, R. C. A System of Instruction in Quantitative Chemical Analysis; Wiley: New York, 1871. 18. Doran, R. L.; Tamir, P.; Bathory, Z. Stud. Educ. Eval. 1992, 18, 291–300. Tamir, P.; Doran, R. Stud. Educ. Eval. 1992, 18, 393–406. 19. Beasley, W. F.; Heikkinen, H. W. J. Chem. Educ. 1983, 60, 488–489. 20. Johnstone, A. H.; Letton, K. M. Educ. Chem. 1991, 29, 81– 83. 21. Bramstedt, W. R.; Korfmacher, W. A.; Layloff, T. J. Chem. Educ. 1973, 50, 252–255.


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Teaching Chemical Technique A Review of the Literature

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