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parts of the problem to be solved. These procedures are given names that
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1994 Book DidacticsOfMathematicsAsAScien
parts of the problem to be solved. These procedures are given names that can then be used within other procedures. In some programming environments, the word macro is used to describe a sequence of instructions that can be named so that the programmer can use the macro without having to think about the details of its definition. In the computer programming world, there are often standard ways of solving particular problems, for example, the problem of sorting a set of numbers. The word algorithm is often used to describe a series of instructions to solve a specific problem. From a programming point of view, some algorithms are more efficient than others (e.g., in terms of time and memory). An emphasis on standard algo- rithms, pre-written macros and efficiency is clearly important for effective computer programming, but is not, I suggest, where the emphasis should be placed when programming in the mathematics classroom. My own personal experience of computer programming illustrates the dramatic way in which it has changed over the last 25 years. In 1966, as a university student, I attended a one-week Algol programming workshop, which consisted of lectures and hands-on experience. This hands-on experi- ence involved spending hours typing a program on a set of punched cards (a Rosamund Sutherland London 1. INTRODUCTION AND BACKGROUND R. Biehler, R. W. Scholz, R. Sträßer, B. Winkelmann (Eds.), Didactics of Mathematics as a Scientific Discipline, 177-187. © 1994 Dordrecht: Kluwer Academic Publishers. Printed in the Netherlands. piece of card containing data in the form of punched holes) and waiting at least overnight for the program to run only to discover that typing errors had been made, errors that were difficult to identify because the punched code had to be translated into the computer language before it could be read. So, at this time, it was very important to plan a program in advance, and it was very important not to make syntax errors because these cost time. In no way was it possible to interact with the computer code as it was interpreted and evaluated by the machine. Things began to change with teletype terminals, which were attached to mainframe computers, but these were very un- friendly, feedback could be slow, and the link to the mainframe computer was often fragile. Nowadays, we can write sophisticated programs on a portable computer, interacting with the language in a negotiating way. Professional programmers have responded to these technological changes, but in the educational world (i.e., the world of teaching and learning pro- gramming), a "mainframe mentality" often prevails. This can result in an over-emphasis on planning away from the computer and an over-emphasis on a directed form of teaching. Nowadays, there are many possible ways of interacting with a computer program, and so it is interesting to question why so many university computer programming courses are still taught in ways that are similar to those used 25 years ago. Lack of computer provision, or student numbers, is often given as a reason, but, in my opinion, the reason is more related to the need of the teacher to hold onto knowledge as a means of power and control. Also, if, as a teacher, you have a strong model of learning as being related to both the ability and developmental stage of a student (possibly influenced by Piaget's theories), then you have more or less rid yourself of the responsibility of changing your teaching method. We now know that elementary school children can program in Logo (Noss, 1985). This knowledge has not revolutionized the teaching of programming, it has merely resulted in the marginalization of Logo as a programming lan- guage. 178 THE ROLE OF PROGRAMMING 2. PROGRAMMING IN THE UK MATHEMATICS CLASSROOM In the UK, programming in school was firstly the province of school com- puter science courses, a new subject taught and examined to 14- to 16-year- olds. This subject was often taught by the mathematics teacher, and the pro- gramming language used was almost always BASIC. So there developed, in the UK, a body of secondary school mathematics/computer science teachers with an expertise in BASIC programming. Most of these teachers were men and most of the students studying computer science were boys. BASIC pro- gramming began to be used by mathematics teachers in the mathematics classroom, and it was this activity that was greeted with such enthusiasm by the mathematics inspectorate as expressed by Fletcher: Some years ago I saw the heartening, indeed amazing, response when microcom- puters were first introduced into schools . . . excellent work was done when stu- ROSAMUND SUTHERLAND dents were encouraged to explore, to investigate things which interested them and to find their own way forward. (Fletcher, 1992, p. 1) When Logo became available on small computers (in about 1982) and started to be used in schools, it challenged the BASIC programming com- munity for a number of reasons: Firstly, young children began to learn com- puter programming, and, secondly, Logo was difficult to learn for those who had previously programmed only in BASIC. This relates to the recur- sive control structure of Logo, which cannot easily be followed in a step-by- step way. Thirdly, Logo came with a whole set of ideas about the philoso- phy of teaching, ideas that have become polarized as learning by discovery. Many of us who have carried out research and development with Logo no longer accept this polarized view of learning and have extensively written about the issues surrounding the teaching and learning of Logo (Noss & Hoyles, 1992; Sutherland, 1993). The tensions and debates about the relative value of Logo and BASIC in the UK mathematics curriculum, which now seem very outdated, have nev- ertheless resulted in an equal share being given to both programming lan- guages in the new National Curriculum for Mathematics. For example, in the strand related to algebra, it states that students are expected to follow Download 5.72 Mb. Do'stlaringiz bilan baham: |
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