ReneC G. Ford
Center for Programed Instruction New York, New York
Evaluating a Chemistry Program.
How should one evaluate a chemistry program? Unfortunately, it is not possible to evaluate a program simply hy examining its contents the way one appraises a new textbook. The effectiveness of programed instruction is det,ennined by the way students respond to working with it. Whereas textbooks are all t,oo often writt,en for teachers rather than students, programs are written strictly for students. However, there are certain criteria one can apply in mak'mg a preliminary judgment. Just as a textbook cannot contain inaccuracies, a program which makes misleading statements is also unacceptable. I do not refer here to obvious misstatements, since it goes without saying that they are as unwarranted in a program as in a textbook, What I am referring to is a fault unique to programed instruction. One reason for its occurrence is a prevalent misconception that the exigencies of programing technique justify extreme oversimplification. Because of its incompleteness, this excessive oversimplification can he as misleading to students as an actual misstatement. For example, a program which was written for high school students introduces atomic structure in the following way: A pile of pebbles is described as being as physically reduced to sand and then to powder. The ohservation that individual powder particles are extremely tiny is followed by the statement that each minutepowder particle is made up of even tinierparticles called atoms. Each of the statements by itself is accept,able enough. However, their total implication is that atoms can he obtained by a process of physical suhdivision analogous to reducing pebbles to powder. The inference of incorrect ideas from what is left unsaid is a fault which is specific to programs and therefore difficult to det,ect a t first glance. Another reason for the frequent occurrence of this defect is the very characteristic of programed instruc-. tion which is chiefly responsible for its impressive effectiveness. This is the focusing of attention on the significant material to be learned. To get the point Presented s t the symposium on programed instruction at the 124th meeting of the American Chemical Society, Atlantic City, New Jersey, September, 1962.
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Journol of Chemical Educotion
across it is expedient to be as direct as possible. Therefore, the tendency is to include only the hare minimum of information. This is not always a good idea, particularly with the subject matter of science, since the concepts being taught are seldom black and white. Some degree of qualification is usually necessary to develop the proper perspective. For instance, in another program written for high school students, the definition of a chemical compound stated anywhere in the program, that the composition of all chemical compounds is invariable. Since herthollide compounds are usually not mentioned in high school, they cannot be discussed in this program. Therefore some other qualifying statement is necessary to the effect that compounds with variable composition do exist. If there is no qualifying statement to the contrary, a programed sequencewhichconcludes that all A is B will also imply its converse. Such an implication is frequently incorrect. In evaluating a chemistry program it is especially important not only to look for sins of commission but also to look for sins of omission which can be equally deceptive to the student. Unique Properties of Programed Instruction
There are three properties which uniquely characterize programed instruction. The first is the logical and makes the mastery of fundamental concepts much more likely. The analysis of the subject matter which has to be accomplished to program it successfully is far more rigorous than is generally made for textbooks or lectures. For example, the three laws of chemical change are usually taught set+iatim, immediately preceding the discussion of Dalton's atomic theory. Students seem to have the most diiculty understanding the law of multiple proportions and I found out why when I tried to program it that way. Historians tell us that Dalton predicted this law as a consequence of his atomic theory. When taught in this sequence it makes much more sense. In the program, the student actually follows the reasoning Dalton used when he made his prediction. I t
becomes both an interesting exercise in deductive reasoning and a much clearer explanation than is usually presented. The second characteristic property of programed instruction is that the student's attention is continually directed to what he is supposed to be learning. This focusing of attention on the significant material is at present largely achieved through the responses the student is required to make. We can illustrate by referring to Figure 1. These frames are a t the beginning of a program for high school students on the kine&-molecular theory of gases. This first part. of the program explains what a mental model is and why it. is useful to scientists. Examining frames out of context is especially difficult. Therefore I would like to point out that even though the answers required Response
Question
8.
Smell
Spread, traveled, moved, etc.
Moving, in motion, etc.
When a small bottle of a strong-smelling gas, for instance ammonia, is opened in one corner of a large room, eventually we can it all over the room. I t appears that the molecules of the gaseous ammonia must havfairly quickly throughout the room. To explain this ability of gases to spread out rapidly in all directions, scientists imagine that the molecules of a gas must be constantly (your best guess) ().
Figure 1.
may seem a t first inspection to be obvious, they are demanded by the need to set carefully the initial stage for the idea being developed, namely that molecules of a gas are always on the move. There are two more frames in this sequence followed by a programed black box experiment. The third unique property of programed instruction is that the student plays an essential part in its construction. At every stage in the development of a program the student is the judge of its effectiveness. I have not mentioned "immediate confirmation of response," a phrase frequently used in describing programed instruction. An experiment recently performed by t,he Educational Testing Service in Princeton indicates that this is not quite as essential as previously thought. Briefly, a group of bright tenth grade student,~worked through t,he first 250 frames of my program on the gas laws, in which all the answers were omitted. These students not only kept going even though they never had any sure way of knowingwhether they were correct, but they did remarkably well on an examination written by ETS. The part that really has given us pause is that they performed as well or better than a group of equally bright students who had all the answers! What I have been trying to present in this discussion is an operational definition of programed instruction. The discrimination between a program and a non-program is made in t,erms of what it does rat,her than what
it is. Consequently, appearance alone is not a sufficient criterion for judging a program. We can expect to see programs in the future which bear little or no superficialresemblance to our current Model-T versions. Is i t possible to decide just on the basis of the style of presentation that one program will necessarily be better than another? My own investigations in developing programed instruction in chemistry during t,he past two years have led me to combine both the linear and branching intrinsic techniques, to call for both constructed and multiple-choice responses, and to include frames containing only one sentence and frames several paragraphs long. There are places where t,he student reads without making any responses and other places where he is asked to respond to a question like the following: "Explain why there cannot be a temperature below absolute zero." (This question is the terminal frame in a sequence discussing temperature and kinetic energy.) There also seems to be a general impression that some optimal length is required for individual frames. On the contrary, frames should he as long or as brief as is necessary for both clarity and completeness. I n fact, within a given program unit it is a good idea to vary both the length of t,he frames and the kinds of responses called for. This makes for more interesting programing but, even more important, it affords maximum flexibility in the presentation of the material. Students work as long as an hour a t a time on a program and in general concentrate much harder than when studying from a textbook. Therefore programs should be written in the same kind of lucid, expository prose found in the very best textbooks with a generous sprinkling of clearly drawn illustrations and diagrams. All other things being equal, a well-written program will hold the student's interest longer and consequently will he more effective. However, there is nothing inherent in a particular programing technique that makes it more interesting or a better teaching tool. Since no program can be expected to teach everyone, it is necessary to know t.he student population for whom it is intended. This informat,ion can either he the particular prerequisite knowledge presumed in the program or a description of the minimum ability level needed to learn from it. Also, a program should be accompanied by a statement of its objectives: what the author claims it teaches.' One final criterion for chemistry programs is that they should be maximally self-instructional. Students should be able to learn from them with a minimum of supervision. By working on programs for homework instead of the usual less productive assignments, students could probably learn most of the basic concepts in chemistry on their own. This would make available for other purposes the class time usually spent in teaching these fundamentals. The value of programed instruction in teaching chemistry has impressed almost everyone who has given it a try. By refusing to accept chemistry programs which do not a t least meet these minimum criteria me can discourage damaging exploitation which could prevent this remarkable new teaching technique from being developed to its fullest potential. See previous papers in This Symposium, 4O,ll(l963).
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Volume 40, Number 1 , Januory 1963
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