Many supporters of using simulations to replace science labs point to their interactivity and equate that aspect with the simulation being "experiential." How interactive are simulations anyway? And, is being experiential the best criteria for deciding whether an activity can stand in for a science lab?
Simulations roughly divide into two types: data simulations and procedure simulations. The former focus on generating data for students to use. The latter emphasize step-by-step procedures and generally result in much less data than the data simulations do.
A very early and still popular data simulation involves the trajectories of projectile motion. Various projectiles are fired with different forces with a varying angle. Students observe an animated version of the projectile motion, and the simulation provides data for the student to use. This simulation, although rather simple, provides an excellent model of data simulations in general.
Of course, the equations for this situation are quite easy to calculate if you ignore air resistance, wind, projectile shape and size, and the like. Students have essentially unlimited ability to vary parameters and see what happens to the trajectory. Many people would consider this simulation to be interactive and experiential. But is it?
The same people will tell you that reading a book is not interactive nor experiential. Consider simplifying the simulation solely for explanative purposes. Reduce the parameters to just the launch angle and the precision of the angle to one degree. Allow a range of 0º to 90º. Those choices allow for 91 experiments. The simulation remains interactive in the same sense as it was previously.
Suppose, however, that you recorded those 91 experiments and stored them on a DVD. Now, the student interaction consists of selecting the angle from the DVD menu and watching the experiment play. The data and action remain the same, but the interactivity seems a bit diluted, and the experiential aspect is rather unclear.
Take one more step. Capture the image at the end of each experiment. That image will have all of the data and a static image of the projectile trajectory. You're only missing the animated aspect. Everything you require to understand projectile motion remains. Put each of these images on a page of a book. The student only has to look up the desired angle in the table of contents and turn to the page. Are those actions interactions?
The book contains exactly the same experimental information as the data simulation did. Yet, just about anyone would agree that reading a book is neither interactive nor experiential. Therefore, neither is the data simulation.
Meeting the demand for science education in the 21st century requires better tools than data simulations. Like books and DVDs, simulations may have their place in education, but not in substituting for lab experience.
You'll also find plenty of procedure simulations, especially in chemistry. These simulations require students to use their mouse cursor and mouse buttons to move (drag and drop) images of experimental equipment and materials around on the computer screen. In some simulations, you simply must click on the correct items in the correct order to succeed. Others require that you drag an item to the correct place, and drop it there. Some have predetermined quantities of chemicals, while others allow you to "weigh" a chemical by typing in the desired mass.
As a concrete and simple example, take the analysis of hydrates experiment done in nearly every high school. In the hands-on version, students dry and weigh a small porcelain crucible. They add the hydrate salt to the crucible and weigh again. Next, they cover the crucible, and heat it with a flame long enough to drive the water of crystallization from the salt. After allowing the crucible to cool, they carefully use crucible tongs to move it to the scale for a final weighing.
The change in mass provides a measure of the mass of water lost. The difference in mass between the dehydrated (heated) crucible and the empty one provides the mass of the dry salt. Students are given the molecular formula of the dry salt and proceed to calculate the number of molecules of water in the crystal hydrate for each molecular formula amount of salt.
With a procedure simulation, students place the cursor on the bottle of salt, click to open it, move it to the scale, and so on. In many simulations, they cannot begin until they click on a safety goggle icon indicating that they have put their safety goggles "on." All of this moving about of the computer equivalents of cardboard cutouts has little to do with science.
While scientists may indeed perform operations like these, they aren't the central activity of science. In very many cases, lab technicians perform these activities for the scientists who are engaged in posing new questions, designing new experiments, analyzing data, and preparing papers describing their results. They document the procedure sufficiently well that it may be reproduced in another lab, and that's it.
All scientists should be able to perform the basic operations of their chosen discipline, and schools should be able to graduate future lab technicians. For these people, procedures and their ability to perform them are very important. For the remainder of the students, it's all a huge waste of time. After all, how many students will graduate and find that they must know how to operate a stopcock to perform a titration?
Procedure simulations miss the point of science labs entirely. By focusing on the procedure, they obscure the real science that should be the center of the experience.
The people who promote these simulations point to the value of simulations in training airplane pilots. And that's exactly where procedure simulations have value, if they have any. If a student performs a really good procedure simulation before going into a real lab to do the same procedure, then that student is better prepared and will be more likely to succeed. The procedure simulation does not replace the actual lab, it prepares for it.
Simulations of either kind, data or procedure, should not substitute for actual labs. Data simulations may be useful for visualizations rather than for producing data. Those data are too precise to be of much use in developing a sense of the nature of science anyway. Procedure simulations may be of use in preparing students for a real lab they're about to do. Neither should be considered "experiential."
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