Teaching the General Chemistry Laboratory with GenChem, a Silicon Based Instructor.
Rudolph W. Kluiber
Professor of Chemistry
Rutgers University, Newark, NJ 07102
General Chemistry Laboratory is a time
consuming, labor intensive course which receives mixed evaluation as a teaching
tool. Its satisfactory implementation
depends on blending the background and ability of the students, the interests,
ability and dedication of the instructors, with the philosophical basis for
offering the course.
Rutgers University in Newark, originally
a urban commuter university, retains much of that heritage despite recent
additions of on-campus student housing. For our science majors, two semesters
of a one credit, three hours per week, laboratory is required to be taken in
conjunction with two semesters of a four credit/sem General Chemistry lecture
course. Both laboratories are offered each semester and in the Summer. Our
students cover a wide range of backgrounds and abilities including students
with degrees coming back to college to do their sciences prior to applying for
admission to Medical School. Up to half of our students were not born in this
country. The most common major for our lab students is Biology; we have very
few chemistry majors. There are 250-300 General Chemistry Students enrolled per
semester and usually 70 in each Summer Session. By default, the course is
principally a “service course”.
The laboratory instructors are mainly
graduate student TAs from our PhD program with a few undergraduates. For almost
all of the graduate students, English is not the first language.
Our laboratory is specifically designed
to enhance the lecture material and act as a “chemistry community”. The
scheduled experiments illustrate and expand on the current lecture material but
instead of relying on printed paper, the students direct their questions to the
molecules using the language called experimentation and must interpret the
molecule’s answers.
Students work individually, although
their interaction with peers and instructors is encouraged (except during lab
practicals).
For almost two decades, we have been
developing and using GenChem, a programmed computer which, from PreLab through
Experiment grading and recording and from creating the syllabus through
evaluating student course grades, takes over most of the routine teaching
duties. The current GenChem is a Dell
PowerEdge 2600 Server with dual 1.8 GHz Xeon Processors and 1GB of RAM, running
on Microsoft Windows 2000 (server), original cost about $3000, working
24/7/365. Its web address is… http://genchem.rutgers.edu
Each semester before the students arrive,
GenChem, with the help of its carbon analog, creates a syllabus for both of the
laboratory courses. This allows setting up the entire semester, correlating it
with the lecture and putting it on the web in just a few minutes. In doing this
the previous semester’s records are stored, not destroyed. There is also the
Laboratory Manual which is put together and kept up-to-date, ready for the
printer, via GenChem’s word processing.
On the first day of class, students,
after being assigned to and checking into their lockers, visit GenChem to view
a video on the day’s experiment and then again to start the introductory
experiment. They do this using computers in the laboratory networked in the
same workgroup as GenChem. A student starting the introductory experiment is
also GenChem’s way of setting up a system to keep a record of that student’s
work for the rest of the semester.
What does GenChem do for the student?
Except for the introductory experiment,
before coming to the lab, students must pass a PreLab. This does not count
toward their grade but rather is the “ticket” which allows them to start an
experiment. Each PreLab is created by
GenChem and individualized to prevent mindless copying. PreLabs are web based
and can be accessed from anywhere with an internet connection.
Passing
requires correctly answering:
1.
an individualized problem set or balancing equations based on the
experiment.
2.
seven of eight multiple choice questions. Each of the eight question
categories have five to ten different questions so repeating the multiple
choice questions results in new but similar questions being asked.
A student may enter PreLab information
into the computer as many times as necessary without “penalty”.
GenChem automatically records a
pass. Retaking the quiz but doing
poorly cannot “un-pass” a student.
Passing the PreLab is verified by GenChem
when the student starts the experiment in the lab.
The PreLabs are designed to help the
student understand the experiment.
Although PreLabs do not count toward the
experiment’s grade, not having the PreLab passed by the end of the day the
student is scheduled to do the experiment produces a 5 point penalty. This provides incentive to keep up.
To assist in passing the PreLab, in
addition to the Manual, there are web pages and web tutorials.
Again
these again are accessed from the syllabus on the web http://genchem.rutgers.edu/Chem113 or http://genchem.rutgers.edu/Chem114
Instead of initial laboratory lectures
for each experiment, there are videos which can be downloaded from
GenChem. These are large files 150-250
MB and generally require a broadband connection, particularly to stream; dialup
may take hours to download. They can be
viewed at home or at school and are accessed from the web syllabus.
Videos rather than a laboratory lecture
by the instructor have many advantages.
Unlike lectures, bad portions of videos can be revised so that they are
correct. Details such as reading a
buret can be made obvious. They can be viewed at any time; this is particularly
important in a commuter school where a traffic tie-up can cause a lot of late
students. They can be rerun to hone in on some obtuse point. Perhaps most important, they can be viewed
before the student comes to class leaving additional time to do the experiment.
Because of GenChem, all of this preparative
work can be done by the student from home using the web before the start of the
lab.
In theory, students arrive at the
laboratory ready to begin talking to the molecules. They work individually
although interaction is usually encouraged.
They start by going to a networked
computer in the laboratory and opening the GenChem experiment program of the
day. Example of the on-screen presentation.
Unlike the PreLab and Videos, these
experiment programs can only be accessed using laboratory computers!
The experiment program verifies passing
of the PreLab, and also presents a short quiz about the experiment which must
be passed. This is the first wakeup for students who did not take the PreLab
too seriously. This quiz covers general principles related to the experiment
and tries to reset the student’s thinking so the experiments are not just
cookbook. They take the quiz until they
pass, although after the third honest failure, they are told to summon the TA
for help. Dishonest guessing is chastised by GenChem.
Early on, GenChem also individualizes the student’s experiment. Everyone does the same experiment, but there are variations in reagents, volumes or masses, and unknowns. It is unlikely that two students working next to each other can share all their data.
The experiments are done in the classical
hands-on manner using burets, beakers, balances etc.
When the experimental work is done, the
student enters the collected data into GenChem. On the initial entry,
GenChem may suggest repeating a
measurements or an observation which appears to be poorly done. Essentially,
GenChem is looking over everyone’s shoulder to warn in real time of a bad
mistake, yet the student can not abuse this generosity by fishing for the right
answer.
Students then do calculations and make
conclusions and enter these into GenChem.
Again, only on this first entry, GenChem will comment on calculation
errors including incorrect sig figs. An example of a calculation warning.
After correcting any experimental or
calculation error, the student can get GenChem to grade their work. GenChem produces an immediate comprehensive
graded evaluation. Graded printout: example 1 example 2 .
Work not done in a timely manner is penalized by GenChem with “late points”. Most experiments must be graded the day they are started. All of this laboratory work can be entered by the student into GenChem only while in the laboratory.
For poorly done experiments, repeats are
allowed. The student does a completely
new experiment, generally with new individualization. A 5 point penalty usually applies. It allows students to, rather than talk of things that went
wrong, redo the experiment without errors, if they can. Repeat data sheets are a different color and
TAs are asked to give special attention to students doing repeat experiments so
that there is improvement.
Essentially all of GenChem’s restrictions
can be overridden by the Professor in charge.
In addition to the regular experiments,
students can do “short, simple, significant” extra-credit experiments. These are taken from our PlayChem menu http://genchem.rutgers.edu/PlayChem
These are generated and graded by
GenChem. They take about an hour to complete and five of these are offered per
semester. In total about 100 extra
credit points can be generated. These
experiments are meant to be mildly challenging. The TAs are asked not to
provide material help; the students are to figure out the answers
themselves. Interaction among student
doing the extra credit is encouraged.
In the first semester, currently we are
using: SteelWool, MolRat,
CanCrush, MoneyCule, Putty&Slime.
In the second semester, currently we are
using: BreathAlyzer, Bleach,
Ice, Alchemy, Paradox.
These
extra-credit experiments are completely controlled by GenChem except grades
must be entered into the computer by the professor using an automated system
built into the program, thus ensuring some human contact.
GenChem automatically keeps extensive records of data entered both in the current semester and in past semesters. This proves useful to detect copying or to make corrections if there is an error in an unknown.
GenChem keeps track of time to do an experiment.
At the end of the semester, GenChem gives
the student their course grade. Grading is on an absolute basis; points on
experiments, extra credit, and exams are additive. Cutoff points remain constant semester to semester.
All students can earn an A in the course; there is no curve; there is no quota. The average lab grade is B. In different semesters there have been 35-40% and also 10-15% A grades.
Students can access their grade record at
any time using the web. This record is
given in terms of “Total Points” and
potential letter grade at the current point in the course so students know
immediately how they are doing.
Student evaluation of PreLabs……………. 4+
Student evaluation of videos……………… 4+
The
PreLabs and Videos are always highly rated by most students.
Help provided by lecture to the lab
material… 3.2
Help provided by the lab to lecture
material… 3.7
Student
consistently say the lab is more helpful in understanding the lecture than the
lecture in understanding the lab.
How GenChem Runs
PreLabs are Active Server
Pages using html and VB Script.
VIDEOS were made using a Sony DCR VX2000
camera and edited using Microsoft Visual Studio. They are put on the web in the
.wmv format
Web Tutorials are PowerPoint
presentations.
All the programs for use only in the lab
are written in Visual Fortran.
We have found one computer for 2 students
works very well. A 1:3 ratio is
probably the minimum.
Everybody hates a computer.
GenChem communicates in print. Some
students can’t or do not read.
Although it emphasizes
safety, GenChem is poor at enforcing laboratory safety rules at the bench.
Although it tries to be human, GenChem is
a machine with too few human qualities.
It’s not very people friendly.
Although it warns student to enter data
in ink and not to erase on data sheets, GenChem cannot enforce these.
GenChem can grade short answers but not a
write-up.
GenChem grades both quantitative and
qualitative experiments, it does not grade synthesized products.
GenChem does not walk around the lab or
check experimental setups.
GenChem takes over most of
the tedious grading and record keeping of our General Chemistry Laboratory.
GenChem allows the carbon instructor to
concentrate on the more fun parts of teaching, interaction with students.
GenChem provides easy synchronization
with Lecture and Lab.
GenChem provides consistency, student to
student, section to section, semester to semester, year to year.
GenChem provides both equal and timely commentary
on every student’s work, every day.
GenChem “talks” to every student every
time.
GenChem is both accurate and reliable, 24/7/365.
GenChem provides individualization which
reduces mindless copying.
GenChem reminds every student to wear eye
protection at the start of an experiment.
GenChem tries to make sure students
understand the material before starting an experiment.
GenChem keeps records which are useful
especially where copying or cheating is suspected.
GenChem is always there; doesn’t
disappear from the lab. Students always
must interact with GenChem.
GenChem rewards both ability and effort.
GenChem allows many different experiments
to be carried out simultaneously; controlled chaos in the lab.
GenChem grades on an absolute basis. Every one can earn an A.
GenChem allows using peer
instructors. GenChem, not the
instructor does the grading.
GenChem’s network of computers allows the
occasional use of Vernier LoggerProÔ for data collection.
GenChem demands
accountability: Students strive to leave the
lab with the best grade rather than
the fastest time.
Originally GenChem appeared to have a serious flaw when used at a PhD granting institution. Unlike its carbon counterpart, it does not do RESEARCH!
Yet that is not absolutely true. It reaches every student and can be programmed to ask any question. It has the potential to measure response times and perhaps even track eye movements. It stores records which it can easily search. Potentially, it can get “into the head” of a student.
As a mundane example, this semester in the introductory experiment, in addition to weighing a penny and a beaker on different balances to establish experimental error, sig figs and “conservation of mass”, we also had the students measure the diameter and the circumference (by rolling) of a penny. GenChem plotted the student’s results as a diameter vs (circumference/diameter) printout. Although all students were acquainted with P, less than half recognized that the (circumference/diameter) quotient defines P.
GenChem can pinpoint what it or its carbon analogs should emphasize.
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