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The Kid Should See This

How are bowling balls made?

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Making a bowling ball is more complex than simply making a sphere of solid resin and drilling three finger holes into it. Nested inside a pro bowling ball hides an asymmetrical core. These weights take on a variety of futuristic-looking shapes that, as PopSci explains, “leverage the laws of physics to help skilled alley jockeys throw a strike on most rolls.”

See just one style of these cores in this “how it’s made” video about mass-produced bowling balls in one South Korean factory. The All Process of World YouTube channel documents each more-complex-than-expected step.

asymmetrical core
inside bowling balls
More from Wired‘s One Man’s Amazing Journey to the Center of the Bowling Ball:

“Put simply, RG [radius of gyration] is a measurement of the distance between the ball’s center of mass and the tip of the invisible axis that extends to the ball’s surface. (The technical definition: “The square root of the moment of inertia divided by the mass of the object.”) The lower a ball’s RG, the more spin a bowler can create by applying torque; the higher the RG, the more power required to rotate the ball. The most common analogy that ball designers use is that of a spinning figure skater, who can slow down their speed by extending their arms away from their center of mass.”

filling the molds
smoothing the ball's surfaces
measuring the surface to drill holes
Note all of the robot arms, as well as the laser etching on the ball’s final surface.

Next, watch these hand-picked ball physics videos:
A pendulum wave demonstration with bowling balls
• The Hammer-Feather Drop in the world’s biggest vacuum chamber
• The Stacked Ball Drop (and Supernovas)
• The Physics Behind a Curveball: The Magnus Effect
• Surprising Applications of the Magnus Effect
• Demonstrations of the Coanda Effect using Schlieren optics

Bonus: How does a bowling alley work?

via Kottke.

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