The Molecular Science Project:
http://www.molsci.ucla.edu/pub/explorations.html
GraphLab
GraphLab teaches basic principles and skills for graphing. The program is divided into four lessons: scaling, drawing a "best-fit" straight line, errors, and least-squares fit.
Scaling: Requires students to set the scales for graphs in which the variables that involve direct and inverse proportions and in which the scale involves exponents. Students must provide equally spaced intervals.
Best-Fit: Students move a line with the mouse and place it so that the best fit of the data is obtained. The slope of the line must agree within 5% of the calculated least-squares-fit line.
Errors: Scientific data can contain either random and/or systematic errors. In this lesson, students must place the line to give a best fit and then decide based on the phenomena being described what kind of errors the data contain.
Least-Squares Fit: In this lesson, students draw the least-squares line by minimizing the sum of the squares of the differentials, which is shown on the screen as they place the line on the data. The differentials are also shown to provide a visual sense of the minimization. Finally, students are confronted with an "outlier" when they are drawing the least-squares line. In each section students are presented with clearly stated principles and guidelines for graphing illustrated in an accompanying graph of real data from various science subject areas. Following each new principle, students are asked to summarize and evaluate that information. This informative phase is followed by an exercise phase in which students practice the skills.
Platforms
Windows 95, 98, NT 4.0, and 2000 -
Download Setup Program
Worksheets
Graphlab Description (.pdf file, requires
Adobe Acrobat Reader)
Graphlab Exercise (.pdf file, requires
Adobe Acrobat Reader)
Developer
Stephen Michael Schimpf