After competing his project for the Meneley Elementary School science fair, sixth-grader Cole Craighead now cleans the doorknobs in his house more often.The 11-year-old scientist tested how much bacteria grows on door knobs."It turned out pretty good. The first week the bacteria didn't grow much. The third week there was mild bacteria," he said. "I learned bacteria grows quickly because people have dirty hands. I'm kind of a germaphobe sometimes so I didn't really enjoy the project."Cole's project was one of 240 entered in the fair which included fourth through sixth grade, and one first-grade class project. Hypotheses tested included …