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The Science of Spirals Footballs are typically thrown through the air in one of two ways—end over end or a spiral. The end-over-end plays are usually not planned—sometimes these throws happen on botched plays where the ball is deflected or as a desperate attempt to save a play. Spirals are different. Who doesn’t love a great spiral football throw? We all do, right? Did you know that a really great spiral throw can make an astonishing 600 turns per minute? That’s the same rate that a CD spins in a CD player! It’s amazing! It was mentioned in the previous section that the quarterback controls three factors: > The speed (velocity) at which he throws the ball > The angle of the throw > The rotation of the football The rotation that the

quarterback places on the ball has a direct influence on how the ball will slow down on its path. Certainly the ball is affected by gravity—as the ball travels across the field, gravity pulls the ball in a downward motion. However, the ball is also affected by air drag (resistance). A tightly thrown spiral has less air drag, so the ball will not slow down quite as much. Spiraled balls simply stay in the air longer.

Footballs typically fly in two patterns: end-over-end, or in a spiral.

CHAPTER 1 : THROWING

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