Here are 5 data visualization tools I thought were pretty neat and have applicability to teaching:
1. http://www.wikimindmap.org/viewmap.php?wiki=en.wikipedia.org&topic=algebra. This site creates of mindmap of information contained in wikipedia. This particular example shows one of algebra and can be used to show students just what algebra is.
2. http://www.antaeus-data.com/concepts/about.html. Antaeus is client based software that helps to look at data with several variables. To me, this software is like scatter plots on steroids. This product is beefy but also light enough to be used for high school students when teacher correlation. It also does some neat stuff like superimposing data onto maps so that the information is much more readable.
3. http://www.visualthesaurus.com/trialover/. This was pretty cool and a great literarcy tool. Type in a word and you get a visual representation of meanings with the possibility of exploring like words and meanings. I typed in algebra and spent several minutes going off into pure mathematics and other related subjects! Note: there was a trial version of this software but I believe there is a subscription cost for continued use. In a similar vein, http://www.lexipedia.com looked pretty awesome.
4. Although I looked for predominantly math oriented visualization tools, I had to suggest a few that try to visualize a person’s personality. http://www.psfk.com/2010/05/a-data-visualization-of-your-personality.html and http://www.brainpickings.org/index.php/2009/08/10/mbti-map/. I think these sites are not only fun but would help teachers learn about their students and also help students learn about other students.
5. Fathom from Key Curriculum Press. This is not free, but many schools have site licenses. If not, a teacher can obtain one for about $40. This is a tool that does a ton of stuff. It’s strength is in graphing data and helping with regression techniques. You can import data or create your own data (e.g. flipping a coin or pulling a card from a deck). In addition, you can do a lot of graphical representation with a coordinate plane. For example, you can create a parabola with sliders (similar to Geogebra) and show students graphically what happens to the graph when the coefficients of the graph change. For trigonometry classes you can create the random walk on a coordinate plane and show exactly where a person would “wander” to.