Download Printable PDF Version of Paper

Case study teaching in the Community College
Brahmadeo Dewprashad, Borough of Manhattan Community College
Abstract. Community colleges play an important role in educating and diversify the
STEM workforce as more than 40 percent of recent Science and Engineering graduates
have attended community colleges at some point. Students attending community colleges
are largely from local communities and of a wide range of age and experiences.
However, many of them are academically under prepared. I have found that the majority
of these students do not often see the relevance of many of the core concepts covered in
chemistry courses to their own lives. I feel that lecturing to these students using
PowerPoint presentations based on textbooks (which have been designed largely for
instructor centered instruction and students in selective programs and colleges) is not a
very effective instruction strategy. I have found that engaging case studies can be used to
connect with these students and teach core concepts in chemistry. This essay will share
my experiences developing and using case studies to connect with urban community
college students and teach core concepts in Organic Chemistry and General Organic and
Biological Chemistry. The process of selection of interest-arousing topics relevant to
core concepts, and transforming these into stories will detailed. In addition, the design of
case studies for specific pedagogical goals, and strategies for using them in the
classroom, will be shared. Also, the use of technology and multimedia to engage students
and interest them in the cases will be discussed. An assessment of the effectiveness of my
efforts and some of the challenges involved in developing and using case studies will also
be discussed.
Community colleges play a very important role in educating and diversifying the
STEM workforce. A recent study indicated that 44% of recent recipients of the B.S. and
M.S. degrees have taken one or more courses at a community college, and for minorities
and underprivileged students, the percentage is much higher (1). Community colleges
have open admission policies, offer quality education and job training at comparatively
low cost and this makes them particularly attractive to under-prepared, underprivileged
and working students. These students bring diversity and rich real-life experiences to the
classroom and are not particularly receptive to seemingly abstracts concepts taught via
PowerPoint presentations that accompany textbooks. In fact, many students often
question the need to understanding many of the core chemical concepts as they do not see
connections between such concepts and their career plans and lives. I have found that
engaging case studies, with characters and applications that students can relate to, can be
effectively used to connect with these students and teach core concepts in chemistry.
This essay describes some of my experiences developing and using case studies to
connect with urban community college students and teach core concepts in Organic
Chemistry and General Organic and Biological Chemistry (GOB).
One of the goals of undergraduate organic chemistry is to train students so that
they can write mechanisms for reactions using curved arrows to indicate the flow of
electrons. It is quite a challenge to motivate students to learn how to write reaction
mechanisms. Their disinterest is not surprising given that most commonly used textbooks
do not make a clear connection between a knowledge of organic reaction mechanisms
and its application to understanding biological systems. The result is that a large number
of students do not grasp the fundamental concepts of organic reaction mechanisms and
resort instead to memorizing specific mechanisms for a particular exam or quiz. I was
prompted to develop a case study to teach reaction mechanism after listening to news
item about the liver toxicity of acetaminophen and connecting this to the fact that the
mechanisms underlying its toxicity was of an appropriate level for undergraduates(2).
The case recounts the story of a student who gave her cat half of a Tylenol®tablet
not knowing its potential harmful effects. The cat survives, but the incident motivates the
student to learn more about the reaction mechanism underlying the liver toxicity of
acetaminophen. The case outlines three possible reaction schemes that would explain the
liver toxicity of acetaminophen containing products. Students are required to write a
detailed mechanism for each of the proposed schemes. This provides the students with
practice in writing both ionic and radical mechanisms, the two fundamental types of
mechanisms covered in undergraduate organic chemistry. The case also presents
evidence from the literature that supports one of the reaction schemes and eliminates the
other two. Students are required to identify the correct reaction scheme and propose a
mechanism based on the evidence presented. The correct reaction scheme is not obvious,
but requires analytical thought and some chemical insight. This is valuable from a
pedagogical perspective as it also provides the class with practice in making evidence
based conclusions. In addition, the case study requires students to review and be able to
explain fundamental concepts in organic chemistry such as nucleophilicity,
electrophilicity, aromaticity, elimination reactions, conjugate addition reactions,
functional groups. In the discussions, some students ignored the evidence presented in the
case and instead reported, from the literature, information which seemed to be related to
the case, but did not shed light on the correct pathway and likely mechanism. These
students invariably choose one of the incorrect pathways. This was used as a teachable
moment to show that the scientific process requires analytical thinking rather than just a
restatement of collected facts. Most students felt that the exercise was valuable and that it
enhanced their understanding of organic reaction mechanisms. Students participated
enthusiastically in the case study and many of them had additional questions pertaining to
drug toxicity and organic chemistry.
An awareness of the growing problem of drug abuse and students interest in this
topic prompted me to develop a case pertaining to cocaine abuse and use it to teach
several core concepts in organic chemistry(3). The case is in the form of a classroom
discussion between an instructor and her students. The instructor begins class by telling
the students about a research article that describes efforts to develop a treatment for
cocaine addiction. Thee instructor explains to the students that computer modeling was
used to design a mutant version of the enzyme butylcholinesterase, which was found to
metabolize cocaine to less harmful products 2000 times faster than the body’s natural
version of the enzyme. Several students join in the discussion, which then progresses to
encompass the mode of action of cocaine, the chemistry involved in preparing its various
forms, and the underlying mechanisms of these reactions. This case study focuses on the
chemistry of cocaine to teach a number of core concepts in organic chemistry,
specifically nucleophilic addition reactions, nucleophilic acyl substitution, and cocaine
metabolism. It also requires that students read and analyze an original research paper on
efforts to develop a treatment for cocaine addiction. Use of the case has the added benefit
of raising awareness of cocaine abuse. Students indicated that they found the case
interesting. Their major criticism of the case was that excerpting the information from the
assigned article was challenging and time consuming. However, this was used as an
opportunity to discuss the value of gaining experience in reading (and comprehending)
scientific writings. It was also pointed out that one does not need to comprehend all the
details of a paper, but can often get a gist of the work by reading and understanding
selective portions of it.
Turmeric and its health benefits had been in the news recently. I felt that my
students would be intrigued by a case pertaining to the chemistry of turmeric, particularly
because many of them consume it regularly in their diets. As such, I developed and used
such a case (4). The story is in the form of a dialogue between a couple, Leroy and Mona,
about the surprising change in color observed in the soup Mona has made for their dinner.
Mona explains that she added turmeric to the soup because of its purported health
benefits. Leroy wonders whether she had indeed added turmeric, as the color of the soup
is not the characteristic yellow color of turmeric, but an orange color more characteristic
of saffron. Mona explains that the color of the soup changed from yellow to orange after
she added baking sodium (sodium bicarbonate) to it, in an attempt to speed up the
cooking process. Students read the case and then answer the questions associated with it,
which lead them to review and apply the following concepts covered in organic
chemistry: keto-enol tautomerization, resonance theory, anti-oxidant chemistry, organic
acids and bases, pH dependent hydrolysis of esters and ionization of carboxylate group.
The case generated a great deal of discussion as well as many questions. Students were
surprised, for instance, to learn the chemical principles underlying the softening of lentils
by bicarbonate. Many had thought that the more rapid softening of lentils by bicarbonate
is because the latter catalyzes cleavage of the peptide bond in the lentils during cooking.
Students also had questions as to the chemical mechanism underlying the demonstrated
anticancer activity of turmeric and were surprised to learn from reading the case
references that this is an area of active investigation. They were also surprised to learn
that the consumption of turmeric had a potential negative health effect due to its ability to
chelate iron. In addition, students had questions pertaining to the loss of nutritional value
and degradation of medicinal compound(s) during cooking.
I have sometimes overheard students express the opinion that undertaking some
of the four hour long organic chemistry laboratory experiments was not good use of their
time as they had no intentions of pursuing careers in chemistry, and as such, no need to
develop laboratory skills. In addition, I have noticed that cheating was often attempted in
the form of students copying whole or parts of another’s lab report(s) and or
assignment(s). As such, I developed and used two versions of a case to, not only teach
core concepts from the syllabus, but to address cheating and the value of laboratory
sessions (5). One version of the case was designed to supplement the laboratory session
on the synthesis of aspirin and tells the story of two lab partners who were invited by
their organic chemistry professor to discuss the write-ups of their lab reports. Indications
were that large portions of their reports were identical. The professor indicated surprise
that the students did not put enough individual effort into the laboratory exercise and its
write-up. The students pointed out that the lab pertains to the synthesis of aspirin- an
exercise that they felt provided them with training that they would not likely put to use
beyond the course. After much pleading by the students, the professor gave them a makeup assignment. The assignment showed how the concepts learned from the lab are related
to the stability, mode of action and side-effects of aspirin and aspirin-like compounds.
The assignment also reviewed many of the fundamental concepts covered in the
chemistry of carboxylic acids and their derivatives, and connected them to applications in
the health sciences. The other version of the case was designed for use in the classroom
and tells essentially the same story with minor modifications, such that it pertains to
copying of homework instead of a lab report. Students are required to work through the
assignment given by the professor. In addition, students are required to list some of the
advantages and disadvantages to copying lab reports/assignments and to also provide a
response to a lab-partner/friend who has requested to borrow a completed lab
report/assignment, presumably to copy parts of it. These latter two questions provide an
opportunity to openly discuss academic dishonesty (and more specifically copying), its
likely consequence, and ways to prevent it. In addition, students are required to discuss
the ethical merits of a seemingly misleading advertisement for an aspirin-based product.
The case also addresses students’ perception that many of the organic laboratory and
classroom exercises are often neither engaging nor relevant to their lives. During the
case study sessions it was also noticed that discussions on copying were sometimes
punctured by awkward moments of silences. However, great pains were taken to point
out that the case study was designed, not to suggest that individual students in the
particular class would “copy” others work, but to raise awareness of the growing trend of
cheating in academia such that they can become vigilant and guard against it. It was
noticed that in this case study reports, there was not a single incidence of detectable
copying. Although the long-term impact of the case on students’ ethics cannot be known,
it is hoped that activities such as this, re-enforced by additional ones in subsequent
classes, will in a small way positively impact the behavior and attitudes of students.
A course in General Organic & Biological Chemistry (GOB) or Introductory
General Chemistry is a prerequisite for most nursing and other allied health sciences
programs. In addition, it is also the chemistry course that is offered as a science elective
to non-majors in many colleges. I sought to develop cases that pertain to health and
healthcare to engage students in this course. In order to develop authentic cases, I
collaborated with practicing health care professionals in developing these cases. One
such case is a clinical one in which an elderly patient suffering from dyspnea is seen in a
hospital Emergency Room after having taken the antibiotic, Bacitrin™ that had been
prescribed for her sister (6). The results of her physical exam, arterial blood gas
analysis, and pulse oximetry readings are given. Students are provided with the URLs of
online sources with relevant information needed to complete the case. Many of the linked
references are engaging multimedia presentations covering clinical aspects of the case.
Students are taken through a series of exercises that lead them to make a diagnosis of the
medical condition, and to explain the chemical principles involved in the treatment
options for the patient. In order to ensure that students have the necessary background to
undertake the case, a pre-case assignment is included. I was pleasantly surprised by an
unintended beneficial effect of this case. Students reported that they had found a
discrepancy (perhaps typographical) in one of the peer reviewed medical reference
articles. This provided an opportunity to talk about the need for health sciences
professionals to have a good grounding in the basic sciences, of which chemistry is a
cornerstone. Students asked why the patient had developed methemoglobinemia when
her sister apparently did not, although they both took the medication, Bactrim™. It was
heartening to note that the students had picked this up in their reading of the case and that
they were curious about it. This provided an opportunity to discuss idiosyncratic
medication reactions and patient characteristics (including age) that can contribute to it.
Students added to the discussion their own anecdotes of persons they knew who had also
experienced side effects to medications. They also acknowledged the need for students
(undertaking training leading to health care professions) to be cognizant of such likely
adverse reactions.
Obesity is a very serious and growing health concern in the United States, has not
spared my students and has caught the attention of the general public. As such, I
developed and used an obesity related case study to teach core concepts in GOB (7). The
case tells the story of two friends who go shopping together at a mall. One of them buys a
pair of jeans that does not quite fit her, even after much struggle. The friends then have
what they believe to be “light” lunches as have been invited to a dinner party later that
day at which they expect to eat a lot of food. The story continues with the friends
discussing their perceived calorific intakes and expenditures from walking in the mall. It
concludes with the girl who bought the jeans trying unsuccessfully once again to fit into
them. She takes her weight and waist measurement, and then resolves to lose weight.
Students are taken through a series of questions and exercises that lead them to determine
whether each of the students did indeed have a light lunch, if they in fact “burned off” the
calories consumed during their walk in the mall, and whether one of the characters is
obese and if her diet plans are realistic. The case provides students practice in: using
conversion factors to calculate the energy value of different foods, inter-converting
energy values given in Calories and kJ, calculating percentages, calculating body mass
index (BMI) and understanding its use in categorizing individuals as healthy, overweight,
or obese, calculating the amount of Calories burned during walking and understanding
effective strategies for weight maintenance. This case study generated much interest and
students sought additional information on calorific values of other foods, obesity related
illnesses, and weight loss products. Such questions were addressed very briefly and
students were directed to additional readings on the topic
I have found that use of case studies help me engage and connect with students.
Their use usually generates many office visits which were often leveraged to motivate
students to put even greater effort into studying for and succeeding in the courses.
Developing and using the cases have also made me reflect on my own teaching and
identify ways to improve it. I encourage other chemistry faculty members to consider
using / developing and using case studies in their classes. It is an effective way to engage
students and provide practice in applying concepts to solve problems in students’ areas of
interest. It is perhaps worthwhile for us to reflect on the fact that from time immemorial,
stories have been used to pass on values, beliefs and knowledge, and to stimulate
imagination and our own memories of how transfixed we were, listening to stories during
our childhood and the lessons learned from each one. It is not advocated that case studies
be used at all times instead of lectures as there are also several challenges to using case
studies. The biggest challenge is finding cases to teach all of the core concepts in
chemistry. In addition, using case studies requires special efforts in classroom
management. This is because good case studies connect so well with students that their
undertaking can very easily lead to broad-based discussions on case, and away from the
chemical concepts covered by the case. In addition, careful time management is required.
Assessment of individual student learning and efforts also requires some thought,
particularly when the case is done in a group format. However, the use of case studies do
help instructors connect with students, students connect with each other and see the
relevance of chemical concepts to their own lives. As such, teaching some topics with
case studies can be a worthwhile and practicable effort.
References:
1. Moore. J.W. 2004. “Scientists, Engineers and Community Colleges”. J. Chem.
Educ., 81, 1239.
2. 13. Dewprashad, B. 2009 “Cats Have Nine Lives, But Only One Liver: The Effects of
Acetaminophen.” Case Study Collection, National Center For Case Study Teaching,
University of Buffalo. http://sciencecases.lib.buffalo.edu/cs/files/2-acetaminophen.pdf
and Journal of College Science Teaching 38(6): 48-52.
3.Dewprashad, B... 2010. “The chemistry of cocaine” in Case Study Collection, National
Center For Case Study Teaching, University of Buffalo. March 12, 2010.
http://sciencecases.lib.buffalo.edu/cs/files/cocaine_chemistry.pdf.
Accepted by Journal of College Science Teaching
4. Dewprashad, B. 2010. “The Chemistry of Curcumin, the Health Promoting Ingredient
in Turmeric.” Case Study Collection, National Center For Case Study Teaching,
University of Buffalo, February 10, 2009.
http://www.sciencecases.org/curcumin/case.asp and
Journal of College Science Teaching. 39(1) 56-60
5. Dewprashad, B. 2009. “Commonly used painkillers Chemistry and mode of action.”
The Chemical Educator., 4(6):247-249.
6.Dewprashad, B.; Vaz, G.; Vaz, S .2010. “A Case of Respiratory Distress” Accepted
for publication in Case Study Collection, National Center For Case Study Teaching,
University of Buffalo.
http://sciencecases.lib.buffalo.edu/cs/files/methemoglobin.pdf
7. Dewprashad, B.; Vaz, G. “A light lunch?” 2010. Case Study Collection, National
Center For Case Study Teaching, University of Buffalo and accepted for publication in
the Journal of College Science Teaching, October 28, 2010.
http://sciencecases.lib.buffalo.edu/cs/files/calorie_chemistry.pdf