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Are Simulations Just a Substitute for Reality?


Harry E. Pence
Chemistry Dept, SUNY Oneonta
Oneonta, NY 13820

06/01/97 to 06/04/97


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.


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. 


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. 


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
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 , 199365 , 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.