Downloaded via EAST CAROLINA UNIV on January 1, 2019 at 10:09:09 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
Chapter 9
Applying Innovations in Teaching to General Chemistry W. Christopher Hollinsed* Chemistry Department, Howard University, 525 College Street, NW, Washington, DC 20059, United States *E-mail:
[email protected] Discipline based education research has made available a host of techniques and approaches to solving the problem of student achievement in higher education. In this work, a specifications grading technique is applied to general chemistry, a freshman class taken by many STEM students. General chemistry has often had a significant, sometimes negative impact on the self-image of freshman students. The creation of a testing regime which maintains high standards while at the same time being forgiving enough to treat early failure as a learning opportunity has the opportunity to have the course serve as positive transformation for the new student, particularly for minority students who may be experiencing other pressures. The application of this technique over several semesters has resulted primarily in the conversion of B students to A students while having no significant impact on reducing the number of poorer performing students.
There has been much attention paid to the increasing societal need for more students graduating with degrees in STEM (Science, Technology, Engineering or Mathematics) fields (1). It has been suggested that for the URM (Under Represented Minority) population, a host of factors contribute to the achievement gap and many institutions have implemented a variety of programs and initiatives aimed at increasing the success of this population. Since our institution is a historically Black university, many of the issues associated with a minority student attending a majority serving institution (race, feelings of not belonging, © 2018 American Chemical Society Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
lack of a supportive peer community, lack of role models among peers and faculty, stereotype threat (2)) are not present to the same extent. The issues with students at a high risk of not achieving academic success should be parallel to those of an inadequately prepared majority student at a majority institution. The intervention suggested here as one of a family of interventions should be applicable for all students regardless of minority/majority status. In general students taking General Chemistry are Freshman and are dealing socially with the transition from high school to college in addition to many having inadequate preparation, (often in the mathematics area) for learning science at the college level. If students pass this introductory course without achieving some level of mastery, they will often struggle in later courses since those courses build on the fundamentals learned in this basic course. Any lowering or softening of the standards risks the University’s reputation since the students will not perform as well on later assessments (such as the MCAT). The average Freshman student at our institution has usually done very well in high school. Since the United States does not have a national education standard or a national education exam (other than the SAT/ACT), the student may have a false sense of his or her ability to learn at the college level. In many, many conversations held with students it becomes clear that students who have done very well in high school arrive at our institution with excellent grades but limited to non-existent study skills. A concern is that students will arrive at college with great aspirations (as well they should!) but will after failing their first exam in Chemistry be forced to reconsider their entire career path sometime around the fourth week of classes. It is clear that a more forgiving yet still rigorous testing regime could be helpful in changing the experience of students in such a course. We describe such a testing regime here and discuss the results after two semesters of using it. The theoretical underpinnings of using such an approach are included. Assessment based approaches have been used successfully at other minority serving institutions (3). The inspiration of this approach comes from a short profile of Joshua Ring at Lenoir-Rhyne University in Chemical and Engineering News (4). In this work Professor Ring developed a set of learning outcomes which he requires each student to pass. This enforces the rigor required, however if the student does not pass the exam for the learning outcome, the student can re-take the exam until it can be demonstrated that the material has been mastered by the student. The rigor is enforced through Specifications Grading (5) covered in detail in the recent book by Linda B. Nilson (6). The technique has been recently utilized by other practitioners in the field (7) as well as by teachers at the high school level (8). In this work, the course was divided into several different categories of learning outcomes which are designated as learning objectives: Essential Objectives: Are foundational concepts upon which other skills depend or are objectives or skills that will be needed in later courses-e.g. organic or biochemistry. General Objectives: Are skills that the student is still expected to know but may not meet the essential criteria
146 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
Math Objectives: Are skills that are needed that undergird the essential objectives. Understanding an essential concept is not useful if the math skills to calculate the outcome are not present. Extra Credit Objectives: Are problems which require somewhat more advanced thinking but are not deemed critical for current or future success. Students are advised that having registered for the class, it is expected that they will master all the essential objectives to get a passing grade in the class. It is also made clear that the general objectives are often the application of the essential objectives and it will be expected by instructors in higher level courses that this material has been mastered as well. An example of the design of such an objective follows. Consider the following problem: In the combustion of jet fuel with oxygen to give carbon dioxide and water, 250 g of fuel is burned in a test reactor. Assume the fuel to be dodecane, C12H26. How many grams of oxygen are needed to support complete combustion of the fuel? Assuming sufficient oxygen is provided, how many grams of carbon dioxide is produced in the reaction of 250 g of fuel? A series of steps will be needed: 1.
A balanced equation must be written (balancing equations: an essential objective): •
2.
The number of moles of 250 g of dodecane needs to be calculated (the molar mass of dodecane needs to be calculated and then the mass is converted to moles. (molar mass calculations, mass to mole conversions both essential objectives, significant figures are a math objective) •
3.
C12H26: (12 x 12.01) + (26 x 1.008) = 144.12 + 26.21 = 170.33/ 250 = 0.681 mole
The number of moles of oxygen needed needs to be calculated (stoichiometry, essential objective): •
4.
2 C12H26 + 25 O2 → 24 CO2 + 26 H2O
0.681 moles C12H26 × (25 mol oxygen/2 mol dodecane) = 8.52 mole O2
The number of moles of oxygen is converted to grams (mole to mass conversion, essential objective): •
8.52 mol O2 × 32.00 g/mol = 272.5 g O2
147 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
5.
The number of moles of carbon dioxide for the 250 g of dodecane needs to be calculated and then converted to mass of carbon dioxide: • •
0.681 moles C12H26 × (24 mol carbon dioxide/2 mol dodecane) = 8.17 mole CO2 8.17 mole CO2 × 44.01 g/mol = 36.0 g CO2
The limiting reactant problem described above could be considered a general objective, but it can be seen as the composite of a series of more fundamental (essential and math) objectives. A list showing the choices made in this work identifying learning objectives as essential or general is presented below: Mathematics Objectives MO-1 Powers of 10, SI units, Precision and Accuracy, Significant Figures MO-2 Exponent calculations Essential Objectives EO-1 Dimensional Analysis EO-2 Classifications of Matter, Properties of Matter EO-3 Atoms: Atomic Theory, Nuclear Model, Atomic Numbers, Mass Numbers & Isotopes, Protons, Neutrons & Electrons, the Periodic Table EO-4 Molecules and Molecular Compounds Ions and Ionic Compounds, Naming Inorganic Compounds EO-5 Chemical Reactions and Reaction Stoichiometry, Balancing equations, Patterns of chemical reactivity, Formula weights, Avogadro’s number, Empirical Formulas from Analyses, Quantitative Info from Balanced equations, Limiting Reactants EO-6 Concentrations of solutions, Solution stoichiometry and chemical analysis EO-7 Quantum Mechanics, atomic orbitals, Many electron atoms, Electron configurations and the periodic table EO-8 Lewis structures EO-9 Elements, Ions, multi-atom, exceptions General Objectives GO-1 Hydrates and hydrate composition calculations GO-2 Reactions in Aqueous Solutions: Properties of aqueous solutions-salts in water, Precipitation reactions – metathesis, Ionic equations, net ionic equations, Gas forming reactions, Acid-base reactions, Oxidation-reduction reactions, GO-3 Thermochemistry: Energy, 1st Law, Enthalpy, ΔHrxn, Calorimetry (q=CΔT; q=mCsΔT), Hess’s Law, ΔHf, GO-4 Electronic structure of atoms, Wave nature of light GO-5 Periodic Properties of the Elements GO-6 Molecular Geometry: Valance Shell Electron Pair Repulsion, Electron Domains/Groups, Shapes, Hybrid Orbitals 148 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
GO-7 Gas Laws Extra Credit Objectives XO-1 Determining an Empirical Formula by Combustion Analysis (from CO2 and H2O formed) XO-2 ΔT from hot metal in cold water XO-3 Molecular Orbital Theory Selection of the objectives as to which is essential or general is up to the individual instructor and will be largely subjective. Logistically, since it becomes more and more difficult toward the end of the semester to find time for re-testing, it is better to push most of the essential objectives toward the earlier part of the semester. The large number of minor calculations in the above limiting reactant problem lead to the secondary issue of cognitive load in carrying out complex but everyday calculations in the general chemistry classroom. It is suggested (9) that the average human can carry 4-7 items in working memory. In the above example, the solution has been broken down into 5 basic steps but some of these are combinations of other steps (e.g. balancing the equation is a process requiring several steps). The student can quickly exceed the 4-7 item allotment in doing this very common problem. Atwood (10) has called attention to how question wording can perhaps unintentionally increase the difficulty of a problem for students. It has been suggested that the additional work required in one of the minor steps in problem solving (for example converting mass to moles) can lead to overloading the student’s short-term cognitive capacity since many of the minor steps are relatively new to the student and may not be calculated as “automatically” as they would be for an experienced practitioner in the field. Students are encouraged to continually ‘off-load’ the conclusions from these minor calculations by writing them on their test paper. In this way, the students maintain responsibility for solving the problem while being appropriately prepared to deal with all aspects of the problem as presented. In this work, problems are carefully worded and on occasion provide the results of some of the intermediate calculations to allow the student to focus on the solution being tested for in the objective rather than having them be derailed by failure to carry out a calculation from an earlier objective. For example, in the above problem, having already tested students on their ability to calculate molar masses, we have in some cases provided the molar masses of the compounds in order ensure that we are testing the limiting reactant concept and not the molar mass computation concept. This instructional scaffolding has been cited as an important means of facilitating student learning (11). The final exam even though structured by objective does not usually have these assists built in to it. By the time of the final it is expected that the student is capable of managing her own time, energy and cognitive load to be able to carry out such a calculation without the assistance. In the first semester of implementation of the above scheme, 7 exams were given in addition to the final exam. Many of these were relatively short. However, in every case, unless a time limit was rigidly imposed, students took the entire 149 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
class period to complete the examination regardless of the instructor’s concept of the time needed to complete the exam. As always there were a few well prepared students who would complete the exam in a very short time and leave early. In addition, students were given multiple chances to take and pass an objective. There were two outcomes resulting from this. The first is that the grading burden on the instructor was overwhelming. Students did not keep track of whether or not they had passed or failed an objective (as observed by Toledo et.al.). It was clear that with no penalty for taking an exam and failing that some students did not study very hard before taking an exam. This was in some cases unfortunately true for some students who took exams as many as four times. Since students did not keep track of their pass/fail grades, some students re-took exams that they had already passed when they did not need to. In recent semesters, only 4 exams (incorporating multiple objectives) have been given and only a single re-take was offered. The final exam was structured by objective and correct answers to questions for those objectives conferred full credit for passing an objective for the course. This served to reduce the overburden of grading on the instructor and made it somewhat easier for students to keep track of their grades. The hoped-for outcomes of this work were reduction in the D, F or W grade percentage and some improvement in the preparation of the students for higher level courses. The results for several semesters is shown below in Table 1, including two semesters from before the utilization of the specifications grading regime was used.
Table 1. Grade comparison with and without specifications grading scheme for several semesters A
B
C
D
F
W
Total
%DFW
Grades after specifications grading used: F17
43
8
4
6
14
0
75
27%
S17
31
10
9
6
4
5
60
25%
Grades from before specifications grading used: F16
27
21
10
5
9
6
72
28%
F15
29
15
9
2
8
4
63
22%
There has been no impact at all on the % DFW. This grading scheme did not have any statistically significant impact on the students who do not do well in General Chemistry. The type of test questions have not changed so unless some other adjustment was made, testing alone should not have had such an impact. What does seem clear is that there are fewer B students and more A students. It is suggested that the higher standard (Pass/Fail at 80%) puts the higher grade within reach of the typical “B” student. In almost all cases, students who pass all the objectives do exceptionally well on the final exam. Since the final exam is 20% of 150 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
the grade, students who do well on the exam can have a significant impact on their final grade. (Conversely a poor final exam performance can have a significantly negative effect on the final grade). Every semester that we have done this, a small handful of students fail the first objective and then never fail an objective after that. This is what is hoped for all students: that the exam result is clear feedback that the level of comprehension has not resulted in the desired grade and that some additional effort or change in studying habits needs to be implemented. The desired outcome of such a testing regime is also better performance in higher level classes. To test this, a survey was sent out to students who had been in the Spring 2017 General Chemistry I class who had gone on to take General Chemistry II. Unfortunately, the number of students responding to the survey was small, however some of the results and comments, specifically regarding the testing regime are instructive: •
•
•
The majority of the students who responded to the survey said that they were well prepared for General Chemistry II and that their Gen Chem II grade reflected that level of preparation. Upwards of 75% of the respondents said that the testing regime made a significant positive difference for them. A few said it was actually detrimental to them. Most of the comments were related to attributes of my teaching other than the testing regime. In particular, the access during office hours and the requirement that students work problems in recitation were rated by most as an important contributor to their success.
Despite the limited data, the testing technique is viewed as a limited success. The technique has been used for two semesters of General Chemistry with ongoing refinements and improvements. In Spring semester 2018 it will be applied to Organic Chemistry II.
References 1.
2. 3.
4.
PCAST STEM Undergraduate Working Group. Engage to Excel: Producing One Million Additional College Graduates with Degrees in Science, Technology, Engineering,and Mathematics; Gates, S. J., Jr., Handelsman, J., Lepage, G. P., Mirkin, C., Eds.; Office of the President: Washington, DC, 2012; pp 1−3. https://obamawhitehouse.archives.gov/sites/default/files/ microsites/ostp/pcast-engage-to-excel-final_2-25-12.pdf (accessed May 25, 2018). Steele, C. M. Whistling Vivaldi and Other Clues to How Stereotypes Affect Us; WW. Norton & Company: New York, NY, 2010; pp 48−54 Carmichael, M. C.; St. Clair, C.; Edwards, A M.; Barrett, P.; McFerrin, H.; Davenport, J.; Awad, M.; Kundu, A.; Ireland, S. K. CBE Life Sci. Educ. 2016, 15, ar38. Arnaud, C. H. Chem. Eng. News 2016, 94, 24–25. 151
Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
5.
Ring, J. Specifications Grading in the Flipped Organic Classroom; DivCHED CCCE: Committee on Computers in Chemical Education. http://confchem.ccce.divched.org/2016fallConfChemP2 (accessed May 22, 2018). 6. Nilson, L. B. In Specifications Grading: Restoring Rigor, Motivating Students and Saving Faculty Time; Stylus Publishing LLC: Sterling, VA, 2015. 7. Toledo, S.; Dubas, J. M. J. Chem. Educ. 2017, 94, 1043–1050. 8. Spencer, K. A New Kind of Classroom: No Grades, No Failing, No Hurry. The New York Times, August 11, 2017. https://www.nytimes.com/2017/08/ 11/nyregion/mastery-based-learning-no-grades.html?_r=0 (accessed May 22, 2018). 9. Sweller, J. Cognit. Sci. 1988, 12, 257–285. 10. Schurmeier, K. D.; Atwood, C. H.; Shepler, C. G.; Lautenschlager, G. J. J. Chem. Educ. 2010, 87, 1268–1272. 11. Kirschner, P. A.; Sweller, J.; Clark, R. E. Educ. Psychol. 2006, 41, 75–86.
152 Kishbaugh and Cessna; Increasing Retention of Under-Represented Students in STEM through Affective and Cognitive Interventions ACS Symposium Series; American Chemical Society: Washington, DC, 2018.
