Putting Chemistry in the Palm of Your Hand
The advent of easily accessible computer technology has had a great impact
upon science and science teaching. Its ubiquitous presence in science labs is
a fact of life, and students now have many opportunities to use computers for
the interpretation and discrimination of data. What has been overlooked so far
is the means of the acquisition of data.
A revolution has resulted from advances in technology and the analog/digital
conversion of data streams. The ability to acquire data directly from sensors
that measure physical properties, such as temperature, pressure, pH, and conductivity,
over timeframes that range from fractions of a second to hours, days, or weeks,
is now a critical part of the process of science.
If we fail to give our students exposure to this part of the scientific method,
we do them a grave disservice.
The use of handheld devices can greatly assist students in science, mathematics,
engineering, and technology to understand the nature of science and to be involved
in meaningful scientific inquiry. Scientific inquiry involves not just the reduction
and interpretation of data to understand its meaning but also the procedures
for the acquisition of the data and the design of experiments to generate the
data.
Beginning in the mid-1990s, the retirement of several faculty from the chemistry
department at the University of Nebraska at Kearney (UNK) and the resulting
influx of new, younger, faculty led to a curriculum review focusing especially
on general chemistry and analytical chemistry. The announcement of funding for
a major renovation of the science building then caused us to consider how a
revised lab layout and structure could facilitate our curriculum.
If we fail to give our students exposure to this part of the scientific
method, we do them a grave disservice. ..
The main result of the review was to terminate the analytical chemistry course,
long a traditional quantitative analysis class, and replace it with an instrumental
analysis course designed for majors, and a more environmentally focused introduction
to analysis. This in turn required us to revise the second semester general
chemistry course and its lab component to prepare students for these new courses.
This was also consistent with an overall desire to ensure that our students
were graduating as better writers and were comfortable using computers in their
classes and career choices.
Chemistry Lab Experience for the 21st Century
According to “Shaping the Future,” a report on undergraduate education
in science, mathematics, and technology by the National Science Foundation,
“... every student should be presented an opportunity to understand what
science is, and is not, and to be involved in some way in scientific inquiry,
not just a ‘hands-on’ experience.”
With support from NSF, the chemistry department at UNK participated in a project
to investigate the improvement of the writing of laboratory reports. As part
of that review, the department established several goals for revising the laboratory
experience in general chemistry. They included:
- Focusing on processes (how to pose researchable questions, how to acquire
information to address those questions, assessing the quality of information)
at least as much as on the transmission of facts.
- Using the vast computational power of modern programmable calculators and
desktop computers to explore science, mathematics, engineering, and technology
concepts and illustrate properties of matter in ways that entice and engage
students.
- Ensuring that students have frequent access to active learning experiences,
in class and laboratory as well as outside of class.
The computer and programmable calculator are now such central components to
the conduct of science that students must be conditioned to the use of them
in all aspects of their science curriculum. The power of a 1961 mainframe
computer is now available in hand-held programmable calculators; the computer
on board John Glenn’s Friendship 7 capsule was no more powerful than
the average programmable calculator that students typically bring to class
with them.
To meet our goals, the department began to investigate ways that the old lab
experiences, which had not changed very much since the mid-1960s, could be
reframed or replaced with new or revised experiments.
Initial Trials
Two members of the department attended a Texas Instruments workshop on the
use of TI programmable calculators with the Calculator-Based Laboratory (CBL)
interface that allows a variety of analog sensing devices to send a digital
signal to the calculator for acquisition and analysis of the data. They recommended
that we pursue this as a means of meeting the goals above. Because several
math classes required the use of the TI calculators we felt that this would
be a reasonable approach. Also, the physics department was having considerable
success using these devices in several of their beginning classes.
Several lab experiments were written and tried out by a student who had been
enrolled in General Chemistry the previous semester. It was decided to pilot-trial
the experiments in the next fall semester with the “trailing”
section of the second half of Gen Chem. Then some surplus Macintosh computers
became available and it was decided to bypass the TI calculators and CBL interfaces
and interface the sensing devices directly to the Macs (via the serial port)
so that data could be analyzed and displayed on the computers.
About two-thirds of the experiments that semester were carried out using this
arrangement. The response of the students was very positive. Several of the
students in the trailing section were repeating the class and they indicated
that the sensing device/computer combination was more interesting and informative
than the way they had done the labs the first time around.
Implementation
The initial positive results allowed the department to establish a new set
of goals for the second semester Gen Chem lab experiences. Building on the
initial results, the department decided to start a general chemistry lab that
emphasized the acquisition, interpretation, and “ownership” of
data by the student; allowed for more open-ended and student-focused experiments;
promoted collaboration between students; and reinforced the place of computational
methodology in science.
Two more semesters of testing out various experiments using the sensing device/computer
procedure allowed us to arrive at a list of about 15 experiments that met
these four goals and provided the preparation for the revised analytical course.
It was expected that in any given semester about 10 of the 15 experiments
would be used, together with four or five that did not use the system.
The Switch to Handhelds
At this point we were ready to start preparing for the experiments in the
regular second semester schedule, i.e. with much larger numbers of students
than in the trial classes. It was at this point that we were notified that
the renovation of the science building would not, after all, include remodeling
of the labs—funding was only sufficient to renovate the infrastructure
and complete fire safety and handicap requirements. Thus, the remodeled labs
with computers built in to our specifications did not materialize.
This created two distinct problems. First, we no longer had enough computers
for the large numbers of students in the regular schedule of the second semester
Gen Chem. Second, the computers, as we were using them, took up way too much
bench space. Adding more to accommodate larger numbers of students would have
severely limited available bench space.
At this point we decided to move the experiments from the computers to handheld
devices that could then download to computers in locations away from the lab
benchtops. Palm IIIxe units were chosen because software to interface them
to the sensing devices had just become available. Sufficient numbers of the
Palm units were purchased initially to allow for a full lab section (typically
22-24 students) if the students worked in pairs. Working in pairs had been
part of the program from the beginning; the students liked that aspect of
the program, and it helped to emphasize collaboration as an integral part
of scientific methodology.
The computer and programmable calculator are now such central
components to the conduct of science that students must be conditioned to
the use of them in all aspects of their science curriculum.
The Palms were used that year in the “trailing” section of Gen Chem,
in one of the regular second semester sections of Gen Chem, in the Chem for
non-majors lab (in a more limited extent), and for a couple of Phys Chem labs.
Student response was very positive. All the good aspects of the use of the sensing
device/computer combination were reiterated, along with the convenience of the
handheld units in freeing up bench space and allowing mobility as needed. The
only significant problem was the periodic failure of some of the computers (older
Macs) to recognize the Palm devices when trying to download data (“syncing”).
This was largely fixed by assigning specific Palm devices to specific Macs for
syncing.
The department was thus ready to fully implement the use of Palm devices as
a major part of the lab experience for the second semester of Gen Chem and as
a smaller part of the lab experience for the Chem for non-science majors course.
By this time the Palm IIIxe was no longer available and so the Palm m105 was
chosen. The choice was limited to those Palm models for which an interface was
available to attach the sensing devices. Initial testing showed that they worked
as well as the original Palm IIIxe units. Also purchased were some new Macs
(iMacs) and some PCs (Dell Optiplex GX150) units. Thus we were ready to convert
all sections of second semester Gen Chem over to a lab sequence that included
10 labs based on the Palms.
Results so Far
What we found was that the Palm IIIxe units continued to work well and gave
few problems, the chief one being the Palms’ reluctance to move easily
between the I-Macs and the Dells. The Palm m105 units, however, began to show
a distressing tendency to lock up their screens so that they became unresponsive
to the stylus. Like the small child, when they were good, they were very good,
but when they were bad they were almost useless. And, of course, both models
used up batteries at a rate of several per unit per semester. Rechargeable batteries
did not do the trick, as they did not seem to have the necessary power level
for any reasonable length of time.
We have a few more hurdles to overcome but the principle has been well demonstrated
that the combination of sensing devices and Palm handheld devices provides a
good, worthwhile lab experience for our students. The combination g'es along
way toward meeting the goals that we set for our Gen Chem lab program. The students
are responding positively and we think that they will be better prepared for
the next level of chemistry lab work.
