A philosophy professor had taught a class for 20 years attempting to disprove God's existence. At the end of each semester, he would challenge students to stand up if they believed in God, knowing none ever had. He would then drop a piece of chalk to break on the floor, claiming God couldn't perform such a simple task. After 3 months of prayer, a new Christian student stood up when challenged. Defying odds, the chalk slipped from the professor's hands and rolled along the floor unbroken, shocking the professor. The student then shared his faith in God with the class.