Chelsey Graves and Kate Guajardo, both sophomores at Bandera High School, could have been excused for feeling overconfident when they competed last month at the National FFA Agriscience Fair in Indianapolis, Indiana. After all, they had made the finals of the prestigious competition last year, finishing third in the Power, Structural and Technical Systems division for a project they completed on the energy production of windmills. With this year’s project, called “Jumping the String: A Comparison Study of the Speed of Sound Versus Arrow Flight Time,” they felt they had made a good presentation to the national judges, but worried that it ...