Passage
A well-folded paper airplane can glide across a room, while a flat sheet of the same paper flutters to the floor after only a short distance. Two students agreed that the folded plane travels much farther, and that both objects are made from the same sheet of paper, but they disagreed about the main reason folding helps.
Student 1: Folding matters mainly because it gives the plane a smooth, pointed shape that slips through the air with little resistance. A flat sheet presents a large surface to the air, so it is pushed back and tumbled, while the streamlined folded plane meets far less air resistance and keeps moving forward. On this view, the more pointed and smooth the plane, the farther it flies, and giving it a blunt nose or flaps that catch the air should shorten its flight.
Student 2: Folding matters mainly because it stiffens the paper and gathers its weight along the center. Stacking many layers down the middle makes the plane rigid and balanced, so it can hold a steady, level glide, while a flat sheet is floppy and bends and cannot keep a gliding attitude no matter its outline. On this view, a stiff plane should fly well even if its nose is not very pointed, a smooth-looking but floppy plane should flutter, and adding a little weight near the nose should help.
