The purpose of creating graphics by plotting points is to use built-in Scheme functions to understand how drawing commands work. By studying patterns, these examples then can be used in future lessons to create variable functions.
This process is used in the teaching of algebra, which starts in the primary grades with arithmetic. When a student learns to add, first blocks and fingers are used as examples to understand the process. Students then build on this primitive operation by adding multiple times.
In algebra the constant numbers become variables represented by a letter. In programming that letter can be a descriptive identifier for the unknown value. Functions can be written which use variable data in the solution of problems. Multiple examples can be used to test the function. A design recipe is used to facilitate the data analysis and planning of the solutions.
Coordinate points are lists of two points, the X and Y values. These lists are called positions (posn) in DrScheme. Recursive functions create loops to repeat a process. In this module student are only USING built-in functions. They are creating examples which can be turned into functions in more advanced programming. This is step 2 in the design recipe in How To Design Programs.
Graphic programming support the TEKS and TAKS objective for problem solving found in all curriculum areas. Special emphasis in algebra and geometry is working with functions, patterns and coordinate points.
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How To Design Programs