Snir, 1993
From Eduwiki
Conceptually Enhanced Simulations: A Computer Tool for Science Teaching
Joseph Snir, Carol Smith and Lorraine Grosslight
Summarized by Jane Pafundi
Introduction
Computer simulations are being used in the classroom more and more. Their use helps demonstrate concepts that otherwise may be too expensive, dangerous or impractical to show. Simulations are built to represent real-world events and some allow for the manipulation of variables that respond as they would in real life. The authors argued this may not be enough. Simulations should also help students understand the theories that unite ideas and the interrelationships between concepts. Gaining this understanding is particularly difficult due to students’ preconceptions that are not altered with the simulations. Therefore the authors propose a new kind of simulation which they call “conceptually enhanced simulations” which would include interpretation of laboratory experiments.
The paper is divided into four parts. First they discussed the three levels of understanding which should be covered in classroom science. The second part dealt with classifying and identifying simulations that can guide student thinking to a more theoretical level. The next section described the development of a specific computer simulation that applied the ideas discussed earlier. Lastly, they reflected on three factors to consider when designing computer enhanced simulations.
Through their research they showed how effective these types of simulations were at bringing about conceptual change. They also described areas for additional research including studying the role of the conceptual simulations alone in promoting conceptual change and whether the way these simulations are used changes their effectiveness.
THREE LEVELS OF LEARNING ABOUT NATURAL PHENOMENA
The authors propose three levels of understanding for science education students. The first level includes learning observable facts and the simple generalizations that are formed from these facts. Examples included observations of an object’s color, size, composition or ability to float and generalizations formed including things like “wooden objects float on water.” At the second level students learned theories that unite these observed facts. Inference is needed at this level to relate different observations or to include measurements. An example such as “why some objects float and others sink in certain liquids” was given. The third level involves students learning “about the purposes and methods of science.” Here the students understand what models and theories are and their purpose as they reflect on good science practices. They described this level as a “metatheoretical” or “metaconceptual” level.
Students have preexisting ideas including “intuitive theories” at all the above levels. Also, they generally do not understand the process of science knowledge generation especially the importance of hypotheses and testing these hypotheses. The authors argue that properly designed simulations can help students make conceptual changes at all three levels.
MODEL SYSTEMS AND SIMULATIONS FOR SCIENCE TEACHING
Gentner’s (1983) work was used as a basis for distinguishing two basic types of analogous model systems. The first “object-attribute models,” included models that represent the object and its basic attributes. Such models include pictures or scale models which show the correct parts without demonstrating relations among parts or to other systems. The other more useful model for science is a “relational model” where the same set of relationships holds true for the real system and the modeled system. An example of a wave tank used to model sound waves was given and described as very different in appearance but similar in terms of the relationships of force and energy.
Model systems can be helpful in understanding new phenomena and also can be used to create simulated experiments. The results of the experiments can be used to predict what would happen in the real system.
For student understanding of analogous systems they must be able to: “1)identify the relevant set of relations in the familial system and 2) figure out how those same relations apply to different elements in the less familiar system.” By age 8 students may be ready to use analogous model systems for understanding science and computer simulations may be an appropriate tool.
The choices made when designing a computer simulation will determine how powerful it is in ensuring student conceptual change. For example, those simulations that provide “pictorial models” of observable observations may extend the range of student experiences but will not necessarily guarantee conceptual change. The goal of simulations should be to make what is “unobservable” in nature “observable.” Not only the concrete, observable features but simultaneously the theoretical concepts need to be visible. This simulates the experience of an expert thinker. As an example the authors described observing a pool cue striking a ball to notice changes in direction and speed with the addition of an arrow to represent a vector quantity to show the theoretical concept of momentum.
Also, designers can choose between iconic or abstract representations or use both. Iconic representations look like the object does in real life and have the advantage of being easily interpreted by the user. Objects represented abstractly may appear as differently sized dots and have the advantage of removing irrelevant details to show fundamental concepts.
When running simulations the programmer can code for a predetermined set of screens or a better model would use relevant physics laws coded in as mathematical formulas to govern the behavior of objects. In this case as students interact with the program the simulations would show how objects react under those conditions set by the students but using the underlying physics laws written in the program code. In this way the simulation resembles actual laboratory experiences with the advantage of allowing for a wider range of exploration by the student. The disadvantage of this type of laboratory simulation and the pictorial computer models is neither guides students in the restructuring of their preconceptions whereas a conceptually enhanced computer simulation will provide that guidance.
TEACHING ABOUT THE PHENOMENON OF FLOTATION AND THE CONCEPT OF DENSITY USING CONCEPTUALLY ENHANCED MODELS.
The authors described the conceptually enhanced model they designed to affect the concrete and conceptual levels of understanding flotation and density and also allow for discussion about metaconceptual issues. They chose four concepts to represent in their model including the mass, volume, density and composition of the material. Through previous research they found that elementary students are beginning to interrelate these concepts with an understanding of weight being closer to what scientists describe as mass. They used different sized colored rectangles with the colors representing different materials placed in a container of liquid shown in cross section. The students were able to simulate finding the mass of an object by placing it on one side of a balance and putting mass units on the other side to balance it. They were able to find volume by matching up standard tiles to the object. They could then find the density mathematically by dividing but without understanding the abstract relationship of density of materials. So they designed a visual representation of density through a square filled with black rectangles. When different materials were manipulated they looked more or less crowded or more or less dense. In this way students were able to visualize density as a property of the material. This same analogous model using spatial crowding to visually represent density can be used with other concepts such as monetary units or thermal phenomena.
The linking of multiple representations is another advantage of computer simulations. In the above example pictorial, verbal and numerical data can all be gathered and linked from the simulation. In their simulation the authors allowed different ways for the conceptual model to be shown such as with dots, numbers, cross hatches etc. They also discussed how their embedding of physical laws into their code allowed for a rich environment for student exploration.
ON DESIGNING ACTIVITIES TO INCREAE EDUCATIONAL VALUE OF CONCEPTUALLY ENHANCED SIMULATIONS
Many advantages for using computer based conceptually enhanced simulations have been discussed. A unique advantage however would be that students can create links among different representations of a concept. In their research the authors found increased understanding of density when using the curricula they designed. Three aspects are important to remember when designing curricula. First, computer models must integrate with laboratory experiences. Second, activities must demand interplay among the different representations such as verbal, pictorial and conceptual for effective conceptual change. Lastly, when using models students must be taught that a model is a representation and should not be taken as a direct representation.
