The Virtual ChemLab Project: A Realistic and ... - ACS Publications

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Teaching with Technology

Gabriela C. Weaver

The Virtual ChemLab Project: A Realistic and Sophisticated Simulation of Organic Synthesis and Organic Qualitative Analysis

Purdue University West Lafayette, IN 47907

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Brian F. Woodfield,* Merritt B. Andrus, Tricia Andersen, Jordan Miller, Bryon Simmons, and Richard Stanger Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602; *[email protected] Gregory L. Waddoups, Melissa S. Moore, Richard Swan, Rob Allen, and Greg Bodily Center for Instructional Design, Brigham Young University, Provo, UT 84602

We have created a set of sophisticated and realistic laboratory simulations for use in freshman- and sophomore-level chemistry classes and laboratories called Virtual ChemLab. We have completed simulations for Inorganic Qualitative Analysis, Organic Synthesis and Organic Qualitative Analysis, Fundamental Experiments in Quantum Chemistry, Gas Properties, Titration Experiments, and Calorimetry. In a previous article (1), we described the concepts and principles that form the foundation for the Virtual ChemLab project in the context of our first simulation on Inorganic Qualitative Analysis. Here we describe Organic Synthesis and Organic Qualitative Analysis. We have used the organic simulation and in this study we provide a detailed assessment of student responses and describe the simulation’s pedagogical utility. The Simulation

General Principles It is important to review the general scope and intent of our simulations as described in our earlier article (1). The purposes of instructional laboratories are (i) connecting the theory of the classroom with the practice of the laboratory, (ii) teaching laboratory technique, and (iii) teaching cognitive (or analytical) thinking skills (2, 3). We believe it is very difficult to create a simulation with sufficient detail and realism that it can effectively teach laboratory technique. Technique must be experienced first hand in the laboratory with real equipment. Laboratory processes or sequences can be simulated, but laboratory techniques should be taught in an actual laboratory setting where students can handle the actual laboratory equipment and chemicals. For this reason, our purpose is not to teach laboratory technique. Our simulations gloss over the “how” of performing specific laboratory functions and, instead, focus on the “what”, “when”, and “why” of experiments, connecting theory with practice and teaching cognitive thinking skills. To do this adequately, students must be presented with a completely open-ended environment where they are free to make the decisions and experience the resulting consequences that they would confront in an actual laboratory setting (1). Simulation Description A detailed description of the organic simulation is beyond the available space for this article, but more informa1728

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tion can be found at our Web site (4) and a representative synthesis and qualitative-analysis assignment outlining how the simulation works, including several screen captures, is provided in the Supplemental Material.W The general features of the simulation include the ability to synthesize products; work up reaction mixtures and perform extractions; use nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and thin-layer chromatography (TLC) as analytical tools; purify products by distillation or recrystallization; and perform qualitative-analysis experiments on unknowns using functional group tests with actual video depicting the results of the tests. The simulation allows for over 2,000,000 outcomes for synthesis experiments and can assign over 300 different qualitative-analysis unknowns. To perform a synthesis experiment, students go to the stockroom and select from 17 different named reactions that are listed in Table 1. Once a reaction has been chosen the student can then select starting materials from a set that has been defined for each reaction, also shown in Table 1. Students can also select a suitable solvent. Once in the laboratory, students build the appropriate experimental apparatus using heat, ice, a condenser, and nitrogen gas. The student can select any of 15 different reagents shown in Table 2. After starting a reaction, students can use thin-layer chromatography to monitor it and then quench and work up the reaction mixture using a separatory funnel. At this stage, the student can perform a counter-current extraction, purify the product, and measure the FTIR and NMR of any product or mixture. In the qualitative-analysis part of the simulation, students must determine the structure and name of an unknown using information based on FTIR, NMR, melting point, and functional group tests. The boiling point and CH analysis data can also be provided. Fifteen different functional-group tests (Table 2) can be performed. Results are shown using actual video clips. A step-by-step description of an example synthesis and qualitative unknown assignment are in the Supplemental Material.W Outline and Scope of the Chemistry Reactions, reagents, and substrates were selected to parallel the content found in typical undergraduate organic chemistry laboratory textbooks and to more fully illustrate

Vol. 82 No. 11 November 2005

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Table 1. List of Available Starting Materials for Each Named Reaction Given on the Clipboard Reaction

Starting Material

1. Claisen condensation

Reaction

Methyl acetate

Starting Material

9. Hydroboration

1-Hexene

Methyl propionate 2. Alcohol halogenation

1-Methyl-cyclohexene

1,7-Dimethyl heptanedioate

2-Methyl-1-butene

3-Methyl-1-butanol

4-Methyl-2-pentene

Benzyl alcohol

10. Aldol

Butyraldehyde

Cyclohexanol 3. Alkyl halide solvolysis

Acetaldehyde

2-Methyl-2-propanol

Benzaldehyde

Benzyl chloride

2,2-Dimethyl-pentan-3-one

2-Chloro-2-methylpropane 4-Chloro-1-butanol

Propionic acid 2,6-dimethylphenyl ester

Chlorobutane 4. Alkene hydration

11. Grignard addition

Phenylmagnesium bromide

1-Hexene

Ethyl magnesium bromide

3,3-Dimethyl-1-butene

Acetone

Styrene

Benzaldehyde

1-Methylcyclohexene 5. Alkene bromination

1-Hexene

Carbon dioxide 12. Benzene nitration

Toluene

13. Friedel–Crafts

Toluene

Cyclohexene

Benzaldehyde

2-Butene 6. Alkene dihydroxylation

Buta-1,3-diene

Benzaldehyde

Cyclohexene

Acetyl chloride

1-Hexene

Benzoyl chloride

2-Methyl-1-butene

2-Chloropropane

1,2,3,4,5,6,7,8-Octahydronaphthalene 7. Epoxidation

14. Acid chloride

Acetic acid Benzoic acid

15. Carbonyl reduction

Benzaldehyde

Cyclohexene

Heptanoic acid

2-Butene 1,2-Dimethyl-cyclohexa-1,4-diene

Cyclohexanone

Cyclohex-2-enol 8. Diels–Alder

Cyclohexylmagnesium chloride

2-Chloronorbornane

Methyl acetylacetate

Buta-1,3-diene

16. Alcohol oxidation

Cyclopenta-1,3-diene (3-Methoxy-1-methylene-allyloxy)-trimethyl-silane

Benzyl alcohol 1-Phenylethanol 1-Methyl-cyclohex-2-enol Acetic acid

17. Esterification

Methyl acrylate

Butanoic acid

2,5-Cyclohexadiene-1,4-dione

2-Phenylacetic acid

Butynedioic acid dimethyl ester

3-Methyl-1-butanol

Methyl propionate

Ethanol

1,7-Dimethyl heptanedioate

Methanol

NOte: Zero, one, or any combination of two starting materials can be added to a flask in the stockroom.

the principles of reactivity and selectivity. The number of substrates available within each reaction far exceeds the standard number of choices normally offered in the undergraduate laboratory. For each reaction, a range of substrates with various substitution patterns demonstrate important differences in reactivity and selectivity. Primary, secondary, tertiary, allylic, and benzylic alcohols and halides are included and their rates of reaction reflect the nature of the mechanism involved. For example, the half-life for benzyl and tert-butyl chloride solvolysis in water is 20 minutes, while norbornyl chloride, a secondary “nonclassical” substrate is 2 hours, and primary www.JCE.DivCHED.org

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halide 1-chlorobutane is no reaction. 4-Chlorobutan-1-ol is also a primary alcohol, yet it benefits from anchimeric assistance and it reacts at a much faster rate giving tetrahydrofuran (THF) and a small quantity of diol within 2 hours. The mechanism of the reaction, that is, SN2, SN1, E2, E1, and so forth, is represented as a consequence of the substitution pattern within each reaction type. A further advantage of the simulation are the substrates and reactions that illustrate regio-, chemo-, and stereoselectivity. A few specific examples follow. Students can be asked to explain such results using steric, electronic, and stereoelectronic arguments.


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Regioselectivity most commonly concerns the position of electrophilic attack with an alkene (Scheme I). Terminal alkenes add the electrophilic portion of the reagent at the C1 carbon to give a secondary carbocation intermediate. This is the favored pathway owing to the enhanced stability of the more substituted carbocation intermediate. Alternatively, attack at the internal C2 position generates the less stable primary cation. The major product is then obtained following attack of the nucleophile at the internal C2 position. A spe-

general scheme Nu−

R + E+

R

R

E

E

2°

Nu +

R

R

Nu−

Nu

E 1°

E

terminal alkene H2SO4 H2O

OH branched alkene

H2O ⴚHⴙ

1,2shift

Hⴙ

OH

cific example is alkene hydration using sulfuric acid with 1hexene. Only the secondary product, 2-hexanol is obtained. 3,3-Dimethyl-1-butene was also included to demonstrate the tendency of branched substrates to undergo 1,2-alkyl shifts. The initial secondary cation undergoes a 1,2-methyl shift prior to attack by water to give a more stable tertiary intermediate and product. Chemoselectivity concerns the issue of group selectivity toward a reagent with substrates where more than one functional group is present (Scheme II). For example, methyl acetoacetate can be reduced by a hydride reagent either at the C3 ketone position or at C1 the carbonyl of the ester moiety. With sodium borohydride, a mild reducing agent, the more reactive group is the ketone and the hydroxy ester is formed. The aldehyde ketone and other possible over-reduction products are not formed in this case. Resonance from the alkyl oxygen of the ester attenuates its reactivity and the more reactive ketone is converted chemoselectively to the alcohol. 1,2-Dimethyl-1,4-cyclohexadiene has two functional groups of the same kind present, two alkenes with different substitution patterns. In this case the more electron rich, tetrasubstituted alkene undergoes epoxidation with one equivalent of the electrophilic oxidant meta-chloroperbenzoic acid (MCPBA) to give the epoxycyclohexane product shown. This reagent does not react with the less electron-rich disubstituted olefin across the ring in this case. The simple idea of stereoselectivity as a consequence of mechanistic constraint is seen in alkene bromination and dihydroxylation with cyclohexene (Scheme III). Bromonium ion formation can only form in a cis-fused bicyclic manner and backside attack by bromide leads stereospecifically to the

+ +

3°

Scheme I. Regioselectivity of an electrophilic attack on an alkene.

Table 2. List of Available Reagents for Synthesis Experiments and Functional Group Tests for Qualitative-Analysis Experiments Bottle Reagents

reduction O

O

OH

NaBH4

O

OMe

OMe O

O

not H

epoxidation MCPBA

O

not

O


1

Sulfuric acid (H2SO4)

Bromine

2

Hydrochloric acid (HCl)

Permanganate

3

m-Chloroperbenzoic acid (MCPBA)

Jones Oxidation

4

Aluminum trichloride (AlCl3)

Lucas Test

5

Borane–THF (BH3)

Periodic Acid Tollens Reagent

6

Bromine (Br2)

7

Sodium borohydride (NaBH4)

Dinitrophenylhydrazine

8

Pyridinium chlorochromate (PCC)

Bisulfite Addition

9

Osmium tetraoxide (OsO4)

Iodoform Test

10

Potassium hydroxide (KOH)

Sodium Hydroxide Hydroxamate Test

11

Lithium diisopropylamide (LDA)

12

Nitric/Sulfuric acid (HNO3)

Hinsberg Test

13

Thionyl chloride (SOCl2)

Hydrogen Chloride

14

Sodium methoxide (NaOMe)

Sodium Iodide/Acetone

15

Chromic/Sulfuric acid (H2Cr2O7)

Sodium Iodide/Acetone and Heat

NOTE: Any reagent can be added to any starting material and solvent combination created in the stockroom. The results of functional group tests are shown on the TV as videos or still pictures.

Scheme II. Reactions showing chemoselectivity.

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trans dibromide product. In contrast, the electrophilic [3 + 2] attack of osmium tetroxide leads selectively to the cis-diol product. Again, the electrophile gives a cis-fused osmate ester bicyclic, which now is hydrolyzed by attack with water at the more electrophilic metal position. (E )-2-Butene is also included as a starting material and gives meso-2,3dibromobutane and chiral 2,3-butandiol exclusively. Diastereoselectivity becomes an important issue when substrates contain a stereocenter as illustrated by cyclohexenol (Scheme IV). This was one of the first examples of asymmetric synthesis. This idea continues with important consequences today in that the most efficient approach to asymmetric synthesis involves the use of stereochemistry already present within the substrate. In this manner, new stereocenters are generated in a controlled manner with reliance on the directing effect of functional groups present. In this case the substrate hydrogen bonds with the peracid, directing the epoxide formation from the same face that bears the alcohol, giving the cis product stereoselectively. The cis product, the only one generated by the simulation, is in reality formed with 24-to-1 selectivity over the trans product. The sterically favored trans product can be selectively formed from the silylether protected cyclohexenol with 10-to-1 selectivity. The classical aldol reaction and condensation conditions are included with various ketones and aldehydes reacted with KOH or acid. Lower temperatures give β-hydroxy ketone products, while higher temperatures produce enones. A more advanced topic concerns the use of preformed enolates, generated by lithium diisopropylamide (LDA), where two stereocenters are generated in the product (Scheme V). The key issues involve enolate geometry and nature of the transitionstate arrangement of the enolate and the aldehyde upon bond formation. The aldol reaction is arguably the most important reaction in multistep natural-product synthesis. These principles form the basis of the current topics of auxiliaryand catalyst-based absolute stereocontrol (7). When the phenyl propionate ester is reacted with LDA, the (E )-enolate is formed. The Ireland model proposes a chair arrangement with the C3 methyl in a sterically favored pseudo equatorial position and the aryl group adopting an s-trans conformation. Reaction with the aldehyde also occurs in a chair arrangement where the lithium of the enolate functions as a Lewis acid for the aldehyde carbonyl. The lowest-energy arrangement shows the aldehyde phenyl group and the C3 methyl of the enolate adopting equatorial positions. The 3D representation of the protonated product maintains this conformation as imposed by the Zimmerman–Traxler aldol model (5). The final zigzag representation then shows the anti aldol product obtained. While this is the only product formed in the program, the actual selectivity is 10 to 1. tert-Butyl ethyl ketone in contrast gives the syn diastereomer as the major diastereomeric product. In this case, the bulky tert-butyl group forces the C3 methyl into an axial position leading to the (Z )-enolate. The chair arrangement of the aldol reaction then places this group in an axial position leading to the syn product. Questions can then be asked concerning the effect of enolate geometry, chair versus boat transition states, and equatorial versus axial positions on the reaction pathway. The open format of substrate and reagent selection allow for the exploration of other reactions that are not present on the standard reaction list. The Baeyer–Villiger and allylic www.JCE.DivCHED.org

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bromination

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Brⴚ Br Br2

Br+ Br

trans

O

dihydroxylation

O Os

OH

O

O

OsO4

H H

OH

cis

Scheme III. Reactions showing stereoselectivity.

directed epoxidation Ar

H OH

O MCPBA

O

O

OH

O

H O

H H Ar ⴝ m−CIPh

cis

Scheme IV. Reactions showing diastereoselectivity.

NLi

Li

N

2

(LDA)

O

O H

O

Ar

H

O

LiO

O

PhCHO

H

O

Li

Ph

OAr E

H

CH3

OAr

H OH

CH3

O

Ph

Ph CH3 H

OAr

OAr OH

O

anti

CH3

O Ph OH

O

syn

Scheme V. Reactions showing aldol selectivity.


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Baeyer–Villiger O

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O O

MCPBA

• Fall Semester 2001: 197 students enrolled; taught by instructor A; students completed the same four synthesis experiments and two qualitative-analysis experiments as during Spring Term 2001.

allylic rearrangement OH PCC

O

Scheme VI. Examples of other reactions not in the list of standard reactions.

rearrangement of tertiary allylic alcohols illustrate this idea (Scheme VI). Cyclohexanone, from the reduction reaction, can be selected and reacted instead with MCPBA to give the seven-membered lactone shown. While this reaction is not listed, it is an important synthetic transformation that illustrates the flexibility and power of organic synthesis. It also served to remind students of other reactions pathways and mechanisms that may be operative. Tertiary alcohols are normally thought to be inert toward oxidation conditions, yet the allylic alcohol shown gives an enone product with high yield. In this case the intermediate chromate ester undergoes a [3.3] rearrangement to give a new chromate ester that possesses a β-hydrogen now disposed for elimination to product. Students are then challenged to account for these observations found outside of the standard list. Evaluation and Assessment

Methods The evaluation of the organic simulation was conducted to document whether the simulation met the objectives of helping students focus on the principles of organic chemistry, how students used the program, and whether they were satisfied with the simulation. We collected both qualitative and quantitative data from questionnaires, interviews, observations, and assessment of performance, between April 2001 and April 2002. During this yearlong evaluation, the “real” experiments performed in the laboratory remained unchanged. These conditions pertained to the evaluation. (Note: A semester is the normal 16 weeks of instruction and a term is 8 weeks of instruction where the class time is doubled.) • Winter Semester 2001: 317 students enrolled; taught by instructor A; students completed a preliminary opinion survey about the organic simulation. • Spring Term 2001: 68 students enrolled; taught by instructor A; students completed four virtual synthesis experiments and two virtual qualitative-analysis experiments.

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• Summer Term 2001: 67 students enrolled; taught by student teaching assistant B and student teaching assistant C; students completed the same four synthesis experiments and two qualitative-analysis experiments as during Spring Term 2001.


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• Winter Semester 2002: 314 students enrolled; taught by instructor A; students completed three virtual synthesis experiments and three virtual qualitative-analysis experiments that were different from previous semesters

We sent online surveys to over 900 students who enrolled in chemistry courses that used the organic simulation (95% response rate), we conducted “think-aloud” interviews with six students (chosen randomly) who used the program, and we observed many other students in the computer lab while they were working on virtual assignments. We analyzed data from the online surveys through descriptive statistics and by conducting several analyses of variance (ANOVAs). We coded data from the interviews and observations and placed it into categories for generalization purposes.

Findings The findings from our yearlong study are first reported semester by semester to demonstrate the ways in which our evaluation results affected the ongoing implementation of the organic simulation specifically and the Virtual ChemLab project in general. Spring Term The organic simulation was implemented first in Spring Term 2001. The lab instructor created six virtual assignments—three synthesis assignments and three qualitativeanalysis assignments—to closely relate to experiments done in the wet laboratory. The three synthesis assignments progressed in difficulty: an “easy” esterification reaction so students could learn how to use the program, a hydroboration reaction, and a Grignard reaction. The three qualitative-analysis assignments ranged in difficulty and were randomly assigned by the software. The students completed their virtual assignments and their wet-lab assignments as the term progressed, the evaluators observed and interviewed, and data were collected. The most interesting finding during this term was the significant jump in the number of A’s on the final examination. The final exam for this course covers material from both the lecture and laboratory assignments, and the content has remained constant over a ten-year period. During this ten-year period, an average of 3 students in 500 received an A on the final exam. (A small number, but there are a substantial number of A᎑ and B+ grades.) This term (with the same instructor), 10 out of 68 students received an A with corresponding increases in the other grades. Even with the relatively small sample size, it is clear that by adding the virtual laboratory assignments, a significant increase in performance in the class was achieved.


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Despite the increase in test performance, the majority of the students had a difficult time understanding the value of the organic simulation. For example, when the students discussed what they liked about the six virtual assignments, students commonly responded in the same manner. One student replied by saying, “Not much, I could learn it faster, however.” Because many students made comments similar to this one, it is clear that these students could not judge the value of the organic simulation, but had a sense that it improved their learning efficiency. From the first semester of implementation, we were able to conclude that students were able to increase their understanding of organic chemistry more than in previous semesters and terms because of their higher exam scores. Summer Term The same set of virtual assignments used during Spring Term were also used during Summer Term. Data were collected in a similar manner. Student feedback was generally positive. Similar to Spring Term, students liked how the organic simulation saved time and looked realistic. This term, however, more students said that the organic simulation was valuable because it helped improve their problem-solving ability and reinforced chemistry principles they learned previously. Students believed they better understood the chemistry from the combination of experiences they received in the actual and virtual labs. This term, however, we did not see an abnormal number of students with higher grades on the final exam because one of the student instructors was a “harder grader” than the instructor from Spring Term. Fall Semester As in Spring and Summer Terms, the same virtual assignments were used. Significant findings this semester were found in results from scores on quizzes and exams. Over the past ten years, the distribution on quizzes and exams had consistently been a bell-shaped distribution. During the Fall Semester this distribution changed to a bimodal distribution. Students were no longer performing in the “average” region, and the average was much higher. Specifically, on the two most difficult quizzes, the average score was 13兾15 (87%) during Fall Semester 2001, whereas before the introduction of Virtual ChemLab in the curriculum it was 8兾15 (53%). Students either performed extremely well on these quizzes or extremely poorly. In addition, with a larger, more generalizable number of students (n = 197), the instructor (again, the same instructor) discovered that her Fall Semester 2001 students were much better at analyzing spectra and answering “why-type” questions than students who took the course during the previous ten years. This trend of better performance on questions that assess higher levels of cognition, however, was not universal with all of her students. The instructor saw a direct correlation with students’ quiz scores and the time students spent on the organic simulation. Indeed, we found that those students who did not spend 1–3 hours using Virtual ChemLab in an average week received scores of 3兾15 (20%), while students who spent 1–3 hours per week using the simulation received scores of 13兾15 (87%) or 14兾15 (93%) (98% confidence interval). The only difference between the course this semester and previous years was the addition of Virtual www.JCE.DivCHED.org

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ChemLab. The higher scores during this semester further demonstrate that Virtual ChemLab positively affected these students’ thinking and learning. Winter Semester The virtual synthesis assignments were changed in Winter Semester from the experiments used in the three previous implementations. The instructor chose to do this to discourage virtual lab solutions from being disseminated between students from semester to semester (but not discourage collaborative learning within semesters). Students were required to complete an esterification, an alkene hydration, and a Diels–Alder reaction. These students were also required to complete three qualitative-analysis experiments, which were also randomly generated by the software. During Winter Semester, evaluators gathered data by the same methods used earlier. After having enough time to be comfortable with the simulation, we asked the instructor what she thought of the program: “Would you continue to use Virtual ChemLab: Organic in the future?” She replied by giving a definitive “yes”. She concluded that, “students are much better at analyzing spectra—a key component of organic chemistry—that has led them to being successful on my quizzes and final.” She also said that since the introduction of the organic simulation, students were more equipped to answer questions assessing higher-order cognitive skills. In other words, since the introduction of Virtual ChemLab, she could ask students to categorize spectra of complicated organic compounds, and she could ask more “why” questions and “what if ” questions. Before, she differentiated students based on their ability to “cookbook”. Now, she can differentiate students based on their mastery of those higher-level skills. General Findings Although individual experiences vary, we have discovered two characteristics of successful students. Interestingly, these characteristics can also be seen in the comments made by the instructor. From several analyses of variance we have discovered within a 98% confidence interval that the students who think that the organic simulation is valuable and easy to use are more likely to achieve a higher grade in the course ( p = 0.0203 and p = 0.0253, respectively). We also discovered within a 99% confidence interval that when students use the organic simulation and want to use an unavailable reagent, the students who say they can adapt by using an equivalent reagent are more likely to achieve a higher grade in the course than those who cannot ( p = 0.0056). In sum, the students who have a positive attitude about using Virtual ChemLab and students who can develop multiple strategies for solving chemistry problems are more likely to receive a higher grade. Previous research has shown that having multiple problem-solving strategies is central to the development of expertise within a domain (6). The evaluation team gathered further evidence from a personality test, the Herrmann Brain Dominance Instrument (HBDI). The HBDI generates twelve numerical values to represent various thinking preferences. Two are cerebral and limbic. Someone with cerebral preferences “can understand nonlinear thinking and verbalize it. They can switch from fact-based, rational functioning to experiential modes” (7). Someone with limbic preferences “is characterized by very


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strong preferences in conservative thinking and controlled behavior with a desire for organization and structure as well as detail and accuracy” (7). People who have high cerebral scores typically choose professions of design engineers, research scientists, and development scientists; people who have high limbic scores typically choose professions in nursing and other disciplines in the “helping profession” with a heavy administrative load (7). Within a 99% confidence interval the lower the limbic score for an individual, the more likely the individual will achieve a higher grade from the course ( p = 0.0075). Within a 99% confidence interval the higher someone’s cerebral score, the more likely he or she is to know what to substitute when a reagent is not available in the organic simulation ( p = 0.056). Furthermore, students who have spent fewer years in college are more likely to receive a higher grade in the course (within a 99.9% confidence interval, p = 0.0002). In general, students who receive a high grade in the organic laboratory course have similar personality traits, often major in engineering and science professions, and are academically younger than others (college freshmen or sophomores, as opposed to juniors and seniors). Lessons Learned From our yearlong evaluation, we have learned four principles associated with implementing virtual chemistry laboratories. First, it is valuable to have a flexible implementation strategy to allow for midyear or mid-semester improvements. Second, there is often a conflict between instructor goals and student goals that needs to be acknowledged and balanced. Third, the implementation of new technology into chemistry courses affects many facets of the department including the students, the instructor, the teaching assistants, the laboratories, and faculty members and staff in other departments, to name a few. Fourth, coupling actual laboratory assignments with virtual laboratory assignments provides an environment where students can develop higher-order thinking strategies that are a necessary part of the chemistry discipline.

Flexible Implementation Strategy The implementation strategy we used in this evaluation was iterative: our process was an implementation, evaluation, reflection, and process change. We closely monitored how students were using the program, what problems they were experiencing, and what benefits using the program showed. Above, we reported a brief summary of our findings each semester or term the organic simulation was used. By using this implementation strategy and by reporting our findings in this manner, we discovered several benefits. 1. Small bugs or unforeseen implementation problems can quickly get remedied without sacrificing the entire research project. 2. By reading the evaluation findings over time, a reader can more accurately judge the value of the Virtual ChemLab program. 3. Evaluating a program over a long period of time allows other areas to adjust to the effects of the program. (For example, when we used the organic simulation at Brigham Young University, many more organic chemistry students were in

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the computer lab and asking questions. This made it very important for the computer lab assistants to brush up on their organic chemistry skills to be able to answer the students’ questions.)

Student Goals versus Instructor Goals As it currently stands, the organic chemistry laboratory course consists of both synthesis and qualitative-analysis experiments. From the students’ perspective, the workload of the course is quite demanding—in fact, many say it is too demanding. The class meets for 6 hours a week in lab and about half of the students spend 10–15 hours each week preparing outside of class. As in many laboratory courses, students are required to record their procedures and observations in a lab book. They are also required to analyze IR, 1H NMR, and 13C NMR spectra for each assignment. In addition, they are required to complete virtual assignments using Virtual ChemLab. Students frequently complain about the workload of this two-unit course, and they often wait to take the class until their last semester of undergraduate work. Many of the students who take the course are enrolled to fill requirements for preprofessional programs. For example, one student said that he enrolled in the course because he “needed it for [his] major and as a course requirement for medical school.” Others say they are taking the course because they need it to graduate, to fill a prerequisite to take the MCAT, to get a greater understanding of the principles in organic chemistry, to get a degree or to get a good grade (whether “good” means “passing” or an “A”). From the many responses of this nature, a great majority of the students agree with another student who said, “I’m just jumping through a hoop with this class.” This student is describing a low level of motivation, which can easily lead to a “cookbooking” mentality. Students are almost saying, “Don’t make me think or understand how or why anything happens. I just want to do the minimum amount of work to ‘jump through a hoop’ so I can get what I want (whether this is a high grade, a degree, etc.).” In general, students like the organic simulation because it reinforces previously learned chemistry principles, even though most see it as a “hoop”. Some of the students, however, like the program because they can “blow things up” and others like the ability to experiment and conduct “what if ” experiments. Two common themes were (i) that many students thought that experimenting in the organic simulation was much faster than experimenting in the actual laboratory and (ii) that many students liked experimenting virtually because it was “less messy” than the actual laboratory. For example, one student said, “It was a much quicker way to practice an experiment than in the wet lab. Also, I didn’t spill acid on my favorite shirt and ruin it in the virtual lab.” The instructor, however, wants her students to understand underlying chemistry principles. Although the conflict between student and instructor educational goals is a reality in any course, we have found that students who put in the time and learn using the organic simulation can analyze data better than students who do not. We are not saying, however, that students are “wrong” in that they are being unrealistic in their requests. We are saying that bringing a student from where she is to where you want her to be, in an educational sense, can only be done well if it is done in a time-effective manner for the students and for the instructor(s), if learner


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support is provided, and if the instruction is appropriately challenging. We are working with the course instructor to better implement Virtual ChemLab into the organic chemistry class to address the student goal of a smaller workload and the instructor goal of understanding chemistry principles.

Instructional Changes Affect Many Facets When we began to use the organic simulation, many more organic chemistry students were in the computer lab and asking questions. Many questions were too detailed for the computer lab assistants to answer, so students turned to their teaching assistants. The teaching assistants were able to answer some of the questions, but they also found that there were questions that were above their ability level. We found that students who used the organic simulation developed their higher-level cognitive skills so quickly that they surpassed the ability level of their teaching assistants. This caused students to be frustrated with their teaching assistants. The students wanted to say to their teaching assistant something like, “you’re supposed to be able to answer my questions. You’re not a good teaching assistant if you can’t.” Although this is a valid expression of frustration, we have found there is a learning curve for teaching assistants and instructors, as well as for students. Until the teaching assistants and the instructors are comfortable with the program and can reach the educational objectives the students are expected to achieve, there is a barrier to the implementation process. Fortunately, the instructor carried this load while the teaching assistants were still overcoming their learning curve. Learning Higher-Order Cognitive Skills A meaningful laboratory experience is an experience where students can focus on underlying chemistry principles, without the kinesthetic details. These kinesthetic details imply more than just laboratory technique. Laboratory technique focuses on how to do something, whereas the kinesthetic details focus more on why something does not happen the way it should. Examples of laboratory technique in an organic chemistry laboratory include the following: using a stream of nitrogen gas when refluxing the reaction mixture, washing an organic phase when isolating a product, and seating filter paper with an appropriate solvent when purifying the product with a Hirsch funnel and vacuum. Examples of kinesthetic details include: being too short to reach the top of a column when running a Friedel–Crafts acetylation experiment, confusing the aqueous and organic layers when isolating a product, and forgetting to add a catalyst to the reagents. We believe beginning chemistry students have difficulty in applying concepts in their first laboratory experience because they feel so “bogged down” by details—both laboratory technique and kinesthetic details—that the combination of remembering, understanding, and applying chemical theory is difficult. In order for someone to be successful in chemistry courses, he or she must be able to understand and apply chemical theory or, in other words, to reach higher levels of cognition in a chemistry environment. Examples of questions to assess higher levels of cognition would be the following. (i) “In this experiment, you extracted caffeine from tea. Instead of using tea, what would you isolate from an extraction process if you used willow bark?” (ii) “If you carried out a Cannizzaro reaction in a deuterated solvent, will any www.JCE.DivCHED.org

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carbon–deuterium bonds appear in the alcohol product? Why or why not?” And (iii), “If you created an ether via an SN2 displacement of a halide by an alkoxide, would you be able to call this mechanism a ‘Williamson ether synthesis’?” By removing kinesthetic details, students who use the organic simulation can focus on answering these types of questions that assess their ability to reach higher levels of cognition. We believe that because Virtual ChemLab removes the kinesthetic details, students can remember, understand, and focus on chemical theory better than they would be able to without the presence of the simulation. Conclusion From our evaluation of the organic simulation, we have focused on providing feedback to those responsible for implementing the virtual laboratories and improving the quality of the implementation. We are encouraged by the level of student satisfaction with the programs. Most students said they liked using the virtual chemistry labs. We think this is associated with the realistic “look and feel” and most students who use the chemistry labs will improve their performance in the course. There is a concern that adding the organic simulation to an already busy course may promote negative reactions among the organic chemistry students. Perhaps most important, we are pleased with the findings that the organic simulation promoted student learning as demonstrated by observations, improved test scores, and students’ self-reports. Acknowledgments We wish to acknowledge the Fund for Improvement of Post-Secondary Education (Department of Education, FIPSE, Contract P116B000799) and the Committee for Instructional and Media Arts at Brigham Young University for generous funding of this project. We would also like to acknowledge Burr Johnson for the outstanding artwork. WSupplemental

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Examples of a synthesis and qualitative-analysis assignments are available in this issue of JCE Online. Literature Cited 1. Woodfield, B. F.; Catlin, H. R.; Waddoups, G. L.; Moore, M. S.; Swan, R.; Allen, R.; Bodily, G. J. Chem. Educ. 2004, 81, 1672–1678. 2. Committee on Professional Training. Undergraduate Professional Education in Chemistry: Guidelines and Evaluation Procedures; American Chemical Society: Washington, DC, 1999; p 10. 3. Lagowski, J. J. J. Chem. Educ. 1989, 66, 12–14. 4. Virtual ChemLab Home Page. http://chemlab.byu.edu/home/ index.htm (accessed Sep 2005). 5. Zimmerman, H. E.; Traxler, M. D. J. Am. Chem. Soc. 1957, 79, 1920–1923. 6. Spiro, R. J.; Vispoel, W. P.; Schmitz, J. G.; Samarapungavan, A.; Boerger, A. E. Knowledge Acquisition for Application: Cognitive Flexibility and Transfer in Complex Content Domains; Britton, B. C., Glynn, S., Eds.; Lawrence Erlbaum Associates: Hillsdale, NJ, 1987. 7. Herrmann, N. The Creative Brain; Quebecor Printing Book Group: Kingsport, TN, 1995.


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The Virtual ChemLab Project: A Realistic and ... - ACS Publications

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