## Wednesday, November 21, 2012

### Geogebra Activities In My Classroom

I have been spending a lot of time playing around with Geogebra lately -- in my algebra and precalc classes. I love this program because of how easy it is to make functions come alive and allow you to tweak things and see the effect they have. Below I have embedded an example of a geogebra activity I made to help illustrate how transformations change the graph of the basic sine curve.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.5 (or later) is installed and active in your browser (Click here to install Java now) If you can not see it, you might need to update or install Java on your computer. If you can see it, play around with the sliders in the corner -- move them and you will see how the graph adjusts. These are concepts that we delve out in more details of course in class, but this is a tool I use at the beginning of the unit to introduce the idea. It is also something I allowed as an option for my students to make at the end of the unit as an assessment of their knowledge. It takes minimal knowledge to create a graph that moves with sliders -- I can show a student how to do that in about two minutes.  But to add to the graph the other colored lines and line segments that make it so clear what a, b, c, and d do require more advanced programming thinking, and a strong knowledge of the keypoints that are on a graph.

I have made other geogebra activities too -- another of my favorites is to make a guessing game of graphs. By assigning some code to a button, you can have geogebra create a new random graph. So I do that, and then create another controllable graph and have the students try to match the random graph. Here is an example I just had my algebra students playing with the other day:
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.5 (or later) is installed and active in your browser (Click here to install Java now)
After a quick demonstration in class, we moved the the computer lab and they spent some time playing around trying to type the equation of the blue line. I could have just given them a worksheet to do, (and seriously thought of it as bad as I was feeling yesterday with a pounding headache) but I preferred this activity instead. It was:

• A change of pace and scenery
• Motivating - there is something satisfying in "getting it!"
• Self-checking. I believe this is one of the most critical points of an drill-like activity in a math class. If students don't have instant feedback that they are doing something correct, or incorrect, they will quickly develop habits that are hard to undo.
If you are interested in learning more about creating geogebra activities like these, be sure to check out future posts.