This site is an interactive learning object that utilizes the GeoGebra tool (see http://www.merlot.org/merlot/viewMaterial.htm?id=274019) to investigate lines and their equations. It contains three interactive windows where the student can move points and pieces of a line construction to see the effect on the line and its equation.
To understand the relationship between the graph of a line and its equation.
Target Student Population:
Beginning algebra students.
Prerequisite Knowledge or Skills:
Knowledge of the coordinate plane and equations and their coefficients.
Type of Material:
An instructor can use this to present lines and equations or can assign activities for students to work on.
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Evaluation and Observation
This learning object contains every aspect of a line and its equation. As a student moves a point or other piece of a line, the equation dynamically changes. For the first window, the slope and y-intercept is shown both in the equation as the coefficients and alone. The student has the ability to change the window, the fixed point, the slope and the y-intercept. For the second window, with a given fixed point, the student can change the slope and watch the effect of everything else. For the third window, with the slope fixed the y-intercept can be changed or with the y-intercept fixed, the slope can be changed. There is sound use of color coding throughout.
There is too much information given on each screen. A beginning algebra student will get lost in the details and will lose the main point.
The explanation of the first window does not match what the first window is all about. Two links in the bottom of the page point to non-existing locations.
Potential Effectiveness as a Teaching Tool
For the tactile learner, this can be and effective exploration tool. An instructor can create a set of questions that guide the student through the tool and through learning how the equation of a line is related to the graph of the line.
The beginning algebra student is likely to get turned of due to the number of technical displays that are given. For example there is use of delta x over delta y for the slope, which is notation that this population has not seen before. Also the equation:
LPtLsp(x) = m(x P1) + P2
is not something beginning algebra students can comprehend.
Ease of Use for Both Students and Faculty
The second and third activities are accompanied with explanations that will let the student know what can be done. The slider is simple to use and the dragging the point is also easy.
Since the explanation of the first activity does not match the activity, a student will get very confused about what to do.
The applet windows do not work in Slimbrowser. Two dead links in the bottom of the page create navigation problems.