The use of students for this purpose reminds me of a story about a man who designs a flying machine. After months of calculations and material research, he det

The use of students for this purpose reminds me of a story about a man who designs a flying machine. After months of calculations and material research, he determines that only if he builds his machine out of birch will it be light enough to fly. According to his calculations, nothing else will work. Days later, his best friend is visiting him in the hospital. He carries over a piece of the broken machine. With a puzzled look on his face, the friend asks, "Why did you build it out of pine when you knew you needed birch?" "Because I didn't have any birch."