Introduction
When the topic of simulations has been raised on chemical e-mail discussion
lists, the discussion rapidly narrowed to focus on the question of whether
or not simulations can be used to substitute for hands-on laboratory work.
This is
unfortunate, since this view considers only a small part of the
potential usefulness of simulations. The purpose of this paper is to review
a variety of different types of simulations that may be used by chemical
educators and to urge that simulations should play a significant role in
both introductory and advanced chemistry courses.
Why Is It Important for Chemistry Teachers to Teach About and Use Simulations?
Simulations are becoming as important for some types of scientific
investigations
as beakers and flasks. Many studies rely heavily on simulations, because
direct observation is difficult or impossible. For example, some environmental
problems, such as smog formation or ozone depletion, are too complex and
extend over too broad of an area to be thoroughly understood using only
direct observations. Similarly, molecular simulations of chemical reactions
can offer fast and less expensive ways to identify the probable correlations
between molecular structure and desired reactiv
ity. Even at the undergraduate
level, students should begin to encounter these types of applications, so
that they can better understand modern chemistry.
Simulations are a valuable teaching tool that allow students to explore
chemical systems rapidly and effectively. In some cases a simple graphical
display helps students to understand what is happening at the molecular
level in a way that is much better than traditional approaches. Finally,
the combination of the current popularity of distance l
earning and the recent
decrease in financial support for higher education is leading some individuals
and groups that suggest that simulations can be a replacement for conventional
science laboratories. Unless professional chemical educators can clearly
document the arguments for hands-on laboratories and can show in what ways
they are superior to simulations, there may well be a movement away from
using traditional laboratory experiments in college courses.
What Do We Mean by the Term Simulatio
n?
This question has been discussed at some length on e-mail lists such as
CHEMCONF and CHEMED-L. Although no perfect consensus has developed, a working
definition would seem to be that a true simulation uses a mathematical or
logical algorithm to reproduce the selected characteristics of a system
in such a way that the effect of changing individual variable values can
be observed. The algorithm must be fundamentally related to the system being
considered, and not merely used to select a variet
y of previously created
observations.
Simulations are often confused with visualizations and animations. Wolff
and Yaeger [1] have suggested that a visualization is the process whereby
humans use software to convert a digital array of values into an image.
Notice that, unlike a true simulation, a mathematical algorithm may be used,
but it only serves to convert values from one format to another. There is
not usually any capability for producing truly different scenarios; however,
the visual presen
tation may allow the viewer to extract more information
than would be apparent from a visual inspection of the initial data.
Animations are more difficult to classify since some, but not all of them,
are true simulations according to the definition accepted for this paper.
That is, an animation based on a fundamental mathematical or logical algorithm
and demonstrating the result of changing values for the system variables
would be classified as a simulation. This distinction is, however, not alway
s
as clear as could be desired. As noted below, some research articles that
are described as dealing with animations would appear to be better categorized
as simulations and will be treated as such in this discussion.
Types of Simulations
According to the definition above, pure mathematical models would be the
clearest examples of simulations. These may range from the complex environmental
models mentioned earlier, smog formation and ozone depletion, to simple
spreadsheet calculati
ons. The results can be represented as a complex visualization
or a simple graph. Even a simple spreadsheet calculation can be a powerful
teaching tool, allowing a student to explore how the system will change
when one or more variables are changed.
Many instrument simulations also fit well under the stated definition, although
the interaction may now occur through a more complicated graphical interface
that looks similar to the actual knobs and dials of the real instrument.
In some cases, these si
mulations may also provide a cut-away view of the
instrument, so that the student can more clearly see the function of the
various instrumental components. It is even possible to show aspects of
the operation that would normally be invisible. For example, it is possible
to show the path of the infrared light in a spectrophotometer, even though
the beam would actually be invisible. The key question is whether or not
the light path or instrument output will vary in direct response to the
student's selection o
f instrument settings or new samples.
Instrument simulations are particularly interesting, since they seem to
clearly focus the arguments about using simulations instead of the real
thing. A good simulation can allow the student to vary instrument parameters
in a way that could be difficult or impossible to achieve with any existing
instrument, and so it can be argued that the student gains a better understanding
of how parameters are selected. Unless the simulation is well designed,
however, stude
nts may well view the process as a game that is not related
to actual laboratory work.
True molecular simulations are also extremely useful under the proper conditions.
Often they use a sophisticated calculating engine to determine molecular
configurations and allow the user to observe the effects of changing some
of the variables. This variation extends beyond simply determining bond
distances and angles, to include measuring the effect of structural changes
on the spectra, reactivity and other pr
operties of the system. As noted
by Jones in a paper during a previous CHEMCONF session [2], molecular modelling
programs are proving to be a powerful complement to laboratory exercises.
Students can both see the chemistry at the submicroscopic level and compare
this with what they observe in their experiments.
Many types of computer-based teaching will not be included by the definition
proposed earlier. For example, computer programs that simply present images
without the use of an algorithm or th
e opportunity to control the result
would not be classed as simulations. Motion pictures, computer movies, or
simple animations are extremely powerful teaching techniques that also don't
fall under the definition. It should not be considered that excluding them
from the definition in any way denigrates their usefulness. On the other
hand, a titration program that included a compendium of pictures showing
various stages of the titration process but made calculations to determine
which picture would be shown
would fulfill the requirements.
It should be clear, then, that there are various types of simulations, which
are useful in different situations. In many cases, the simulation is a unique
type of educational experience that has a valid claim to being included
in the undergraduate chemistry curriculum.
Limitations of Simulations
Students must learn to clearly understand the limitations that are inherent
in any attempt to simulate nature. Surely the most fundamental limitatio
n
is the fact that simulations are rule-based, and it is not clear that any
set of rules that is simple enough to incorporate into a computer program
is also adequate to describe the complexities of the physical world. Even
if the governing rules for a given system appear to be simple, the results
may be affected by what John Casti calls the Science of Surprise [3], that
is, the random variations that characterize actual observations.
It may be argued that this simplification of reality is an educa
tional asset
of simulations. By focusing the student's attention on a simple set of rules,
the underlying order of things may become easier to understand. Some educators
express the legitimate concern that in the absence of hands-on experience,
students may confuse the simplified model with reality. This should always
be a concern, and to avoid this confusion it is essential to design the
curriculum so that students can be led to compare reality with simulations,
in order to avoid this confusion in their la
ter careers.
Many of the arguments about simulations may be based on the conflict between
two different views of nature. Some scientists seem to believe that given
enough computer power it would be possible to create an imaginary universe
that could represent an accurate model of physical reality. Others clearly
reject this notion, holding that the physical universe is unique, and any
models that we create can only be inadequate imitations of reality. As virtual
reality programs become more widely
available in the next few years, this
argument may become even more intense. If simulations can reproduce the
physical sensations involved in doing the experiment live, does this make
them more effective, or does this make the simulation more deceptive?
Are Simulations Educationally Effective?
Despite the extensive discussion of simulations on two different chemistry
lists, there has been relatively little evaluation of whether or not simulations
are educationally effective. That i
s, do students learn material better
when they use simulations? In part, this may be a reflection of the fact
that the research in this area has not usually been done by chemists, and
the results that are available do not show a clear conclusion.
One of the common problems with laboratory work is that the students are
expected to simultaneously understand the conceptual background of the exercise
as well as master the physical skills needed to accomplish the experiment.
The conceptual material may
include not only a theoretical framework - why
does an acid-base titration give this shape curve - but also the laboratory
concepts - what are the criteria for choosing the best indicator, etc. On
the physical level, students must master skills such as adding one drop
at a time in a titration or rinsing out a thin column of glass that is a
meter long.
This need to simultaneously master several different types of skills can
make the laboratory very frustrating for students. As Jones has pointed
out
[4], a significant part of the laboratory time is used for relatively
subsidiary activities, such as reading the instructions, writing observations,
and standing in line. Instructors tend to take the position that if students
only learned the concepts thoroughly before they came to laboratory, there
would be little, if any, difficulty. One traditional solution to this problem
is to require the students to do pre-lab exercises or calculations in order
to better understand the conceptual background of the ex
periment. Simulations
might well be used as a more sophisticated and focused type of pre-lab exercise.
Simulations allow the student to focus on a single type of learning. This
may well explain the results of some studies that indicate students prefer
multimedia exercises over conventional laboratory experiences and even seem
to understand the material better when multimedia is used with or in place
of hands-on labs [5, 6].
On the other hand, Bourque and Carlson [7] compared several hands
-on laboratories
with equivalent computer simulations and reported that when the students
were given a 10 question laboratory quiz, those students in the hands-on
group scored better on two out of the three experiments than those who had
used simulations. Unfortunately, the hands-on students were given a tutorial
exercise and a final problem-solving activity, which was not provided to
those who did the simulations, so the comparison may not be altogether fair.
Part of the reason for these apparent
ly contradictory results may well lie
in the way the simulations were designed in the different projects. Mayer
and Anderson [8] suggest what they call the contiguity principle,
namely that multimedia instruction is most effective when the pictures and
illustrations are presented on the same frame to reinforce each other and
allow the learner to build connections between the two types of information.
When the narration is presented before or after an animation, there is relatively
little reinforcemen
t, and the performance of the students show no significant
improvement. It seems probable that simulations may also require contiguous
narration and imagery.
Russell and Kozma [9] created an elegant combination of three representations
of a simple gas equilibrium system in order to test the ability of multiple,
linked representations to improve learning. These consisted of a simple
animation, with balls to represent the atoms, a simple motion picture showing
the color change as the equilibrium shif
ted, and a graph that represented
the relative amounts of each component. They concluded that this system
increased student understanding of equilibrium, but that many students still
maintained misconceptions that they had held when they began the study.
The authors suggested that these continuing misconceptions may have resulted
from the fact that the multiple representation approach made excessive demands
on student's ability to process information in short-term memory.
Probably the most negativ
e result from this type of research is reported
by Rieber et al [10], who studied the effects of a simple simulation on
the learning of Newton's Laws of Motion. They suggest that this approach
produces little improvement in learning for adults, although under optimum
conditions, young children may benefit from this teaching method.
Most faculty seem to feel that students enjoy and benefit from simulations.
Even faculty who question the extent to which they should be used in the
laboratory seem to
agree on this. Although this paper is hardly an exhaustive
survey of the literature on simulations, it appears clear that the research
shows diverse results on the effectiveness of simulations for teaching.
These studies run the gamut from strongly positive to almost totally negative.
In part, this variation may well be explained by the fact that we are still
learning to use simulations. It may well be that the application of simulations
is not as intuitive as one might expect.
Can Simulations R
eplace the Laboratory Experience?
At this time, available simulations cannot replicate the physical experiences
that students would encounter in the laboratory, although virtual reality
programs may soon offer a possibility of accomplishing this. Simulations
do allow the student to focus on the conceptual background without the distraction
of physical manipulations. In some cases this can be quite beneficial. Using
a simulation as a pre-lab preparation allows students to go into the laboratory
with a better understanding of what they will be doing. Laboratory simulations
do not provide a replacement for laboratory, but at least they may improve
one aspect of chemistry teaching that is far from perfect.
Distance learning programs raise important questions about the role of simulations.
Some programs, such as the English Open University, have developed a kit
of experiments that can be sent to the student's home. This not only maintains
the hands-on laboratory experience but also opens the
door for combining
these learner activities with appropriate simulations. Unfortunately other
programs seem to focus more on saving money than the possibility for improving
the educational experience. Probably much of the negative reaction to simulations
is a response to these efforts to replace traditional labs with activities
that can be delivered conveniently over the internet or the phone lines.
If the kinesthetic component of laboratory is important, chemical educators
must state this clearly and expla
in why it is important.
Conclusions
This paper has attempted to demonstrate that the topic of simulations for
chemistry instruction is both complicated and important. In order to prepare
our students to recognize the modern tools of chemistry, it is essential
for chemical educators to introduce simulations into the undergraduate curriculum.
Once they graduate, students will be quite likely to need to use various
types of simulations, ranging from molecular modeling to mathematical m
odeling.
Even more important, these techniques and related methods may well be powerful
teaching tools and so should be explored to the fullest extent.
Discussions that focus on the question "Can simulations replace the
hands-on laboratory?" are quite valid, but may well place the emphasis
in the wrong place. In order to satisfy skeptical administrators chemistry
faculty must be able to answer the question, "What do our students
learn in hands-on laboratories that cannot be taught w
ith simulations?"
Unless we can answer this question clearly, administrators may well ignore
other arguments. Simulations appear to have the potential to supplement
and expand our current laboratory design and create a more effective learning
environment for our students. Finding the best way to integrate simulations
into the traditional laboratory may be the best way to insure both that
instruction is improved and also that the hands-on laboratory component
does not vanish.
Of course, this p
aper is not intended to represent a final word on the topic,
but rather to advance an on-going discussion. It is hoped that it will serve
as a focus that will be useful in the coming on-line discussions regarding
the use of simulations for chemical education.
Acknowledgement
The author wishes to thank the many colleagues who have contributed to the
CHEMCONF and CHEMED-L electronic discussion lists for their help in moving
towards a better understanding of the role simulations shoul
d play in chemical
education. The comments by Gary Bertrand and Allan Smith have been especially
enlightening.
References
1. Wolff, R.S.; Yaeger, L. Visualization of Natural Phenomena, Springer-Verlag,
New York, NY, 1993.
2. Jones, L.L. "The Role of Molecular Structure and Modeling in General
Chemistry", paper 3, On-line Computer conference, " New Initiatives
in Chemical Education." Summer, 1996. Available
at http://www.inform.umd.edu/EdRes/Topic/Chemistry/ChemConference
/ChemConf96/Jones/Paper3.html
3. Casti, J.L.Would-Be Worlds, John Wiley and Sons, New York, NY,
1997, Chap 3.
4. Jones, L. L.; Smith, S.G."Multimedia Education: A Catalyst for Change
in Chemical Education.", Pure and Applied Chemistry , 1993,
65 , 245-249.
5..Smith, S.G; Jones,L. L.; Waugh, M.L."Production and Evaluation of
Intteractive Videodisc Lessons in Labokratory Instruction", Journal
of Computer Based Instruction , 1986 ,13, ,117-121.
6. Haight, G.P.; Jones, L.L. "Kinetics and Mechanism of the Iodine-Azide
Reaction" Journal of Chemical Education, 1987,64
,271-273.
7. Bourque, D.R. ; Carlson, G.R., "Hands-ON Versus Computer Simulation
Methods in Chemistry" Journal of Chemical Education , 1987,
64 , 232-234.
8. Mayer, R.E.
; Anderson, R.B., "The Instructive Animation: Helping
Students Build Connections Between Words and Pictures in Multimedia Learning"
Journal of Educational Psychology, 1992, 84, 444-452.
9. Russell, Joel W. and "4M:Chem: Multimedia and Mental Models in Chemistry"
Journal of Chemical Education, 71, 669-670, 1994.
10. Rieber, L.P. et al, "The Effects of Computer Animation on Adult
Learning and Retrieval Tasks.", Journal of Computer Based Ins
truction
, 1990, 17, 46-52.