Hi HogFan - The "Build Your Own Helio Tracker" Project Idea is an Abbreviated Project Idea on the Science Buddies website. That means it is a suggestion designed to spark your own individual project in a certain area. An "Abbreviated Project Idea" doesn't offer a full Experimental Procedure, as many of our other Project Ideas do. In this case, the project is based on a project that was presented at the California State Science Fair.
If you chose to work on a project like this, you would be building a tracker, but there are possibly a number of areas you could test. As you designed your own project, you would determine your focus. "Why" would you build this tracker? What need does it serve? (The introduction to this project suggests that a helio tracker offers certain advantages. If you built one, is there testing you could do?)
For other Experts, the url for the project is: http://www.sciencebuddies.org/science-f ... p045.shtml
You may also want to consult the Engineering Design Process Guide: http://www.sciencebuddies.org/engineeri ... teps.shtml