A Perfect Spiral

AL BELLO/GETTY IMAGES

STAR PLAYER: Quarterback Kyler Murray has set several passing records for the Arizona Cardinals.

When a quarterback throws a perfect spiral pass, there’s more than skill at play—it’s also a feat of physics. As a football arcs through the air, its orientation changes. At the start of the throw, the nose of the ball tilts upward. Then as the ball descends, its nose tilts downward. What causes this shift? Timothy Gay, a physicist at the University of Nebraska, thinks he has the answer.

A spiraling football spins around an imaginary line called the axis of rotation, which runs from one end of the ball to the other. As the football flies, air molecules push against the moving ball, creating drag. Gay believes this slowing force causes the front end of the ball to rotate around its axis in a tight cone. That eventually causes the football to tip downward—hopefully, right into the receiver’s hands!

Back to top
Skills Sheets (2)
Skills Sheets (2)
Lesson Plan (1)