The Pattel Project
What is a pattern?
A 'pattern' is a concept created by the architect Christopher Alexander. The common definition of a pattern is "an empirically tested solution to a recurring problem". Dr. Alexander describes a pattern in this way:
"Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice."
A pattern language is simply a hierarchical collection of patterns relating to a class of problems. The concept behind a pattern language is that human beings have the capability to piece together solutions to smaller problems in order to solve larger ones much in the same way we piece together words to convey information in natural language.
An example pattern might look something like this:
| Name: | Translating Multiple Representations |
| Author: | SDW |
| Context: | Contributes to larger scale patterns “Introducing New Topic,” “Lecture Design,” “Lab/Lecture Coordination,” and “Language Acquisition” |
| Headline: | Chemists use multiple descriptions of the same process to emphasize particular aspects of the process, to make certain manipulations clearer and easier, and for typographical convenience. Learning to understand all these representations and translate between them is a crucial skill on the road to expertise that is difficult to acquire. |
| Abstract: | Chemists use many levels of descriptions, from macroscopic observations to microscopic interpretations and representations of both levels in symbols and words. Different representations reveal different aspects of the process, and so learning to understand all the different representations is critical to the novice’s development in chemistry. To aid in this process, it is important to not only show the connections between the different representations, but to do so explicitly and repeatedly, and then require the student to practice with the representations. This is analogous to other types of language acquisition, with the added level of pictorial representations. |
| Body: | This pattern manifests over and over at all levels of chemistry, as in many subjects. Similar to learning the “jargon” or “terms of art” in a particular field, the novice has languages as well as content to learn in any new area. The particular area of language acquisition dealt with in this pattern is more than learning new words in a familiar language, such as what concrete objects are referred to by terms like chlorine, sodium, buret, or even to learning a new meaning for a familiar word, such as balance or reduce. Instead this pattern focuses on the layers of different representations used for the same substance. Often these layers are described by the terms macroscopic, microscopic, and symbolic, but even within a particular category (especially symbolic) a given substance or process may have multiple representations. While to the expert these representations are all the same, to the novice they may appear unrelated. The ability to understand these different representations is critical to understanding chemistry. The macroscopic level is what can be observed, but explaining these observations requires relating these large scale behaviors to what is happening on the molecular level – how molecules are moving, colliding, reacting, etc. To describe these activities to another person separated by space, time, or both from the original action then requires using words and symbols that clearly communicate the actions and observations – and confidence that the reader will interpret these symbols as intended. Research has shown that students can solve mathematical problems without being able to solve conceptual questions over the same topic1. Difficulty with reading technical material, particularly in introductory courses, can lead to a lack of comprehension of how the pictures and equations and words inter-relate. However, failing to inter-relate experiences in lab, pictures, animations, words, and reaction equations leads to greater difficulty in mastering the material, as it is stored in unconnected pieces, rather than being assembled into a whole that is easier to recall and use. Explicitly translating between various views in lecture presentations, and then requiring students to do similar activities can result in improvement in learning. It is important to make clear why these different representations all have value and bring out different aspects of the problem otherwise this can look like busywork and lead to memorization rather than learning. References: Gabel, D. L.; Samuel, K. V.; Hunn, D. J. Chem. Educ. 1987, 64, 695-697. Yarroch, W. L. J. Res. Sci. Teach. 1985, 22, 449-459. Nurrenbern, S. C.; Pickering, M. J. Chem. Educ. 1987, 640, 508-510. Sawrey, B. A. J. Chem. Educ. 1990, 670, 253-254. Nakhleh, M. B. J. Chem. Educ. 1993, 70, 52-55. Smith, K. J.; Metz, P. A. J. Chem. Educ. 1996, 73, 233-235. |
| Solution: | Show multiple representations in parallel, explaining why there are different representations and how they are similar and/or different. Use all types of representations to provide cross-references. In a classroom setting, give homework and lab assignments that require students to create, interpret, and translate the different views. |
| Subsystems: | Implementation may require “Effective Multimedia,” “Structure, Guide, Fade,” “Homework Sets,” “Effective Demonstrations” |
Some useful links for patterns: