No-Spin Shot

Let's take a look!

Watch the video on YouTube.

What kind of experiment is this?

Experimental procedure and explanation:

• When the ball is launched without rotating, inconsistent separation vortex form behind the ball, and these vortices flow sequentially downstream. As vortices are formed and released, the ball receives a force from the fluid (air), thereby randomly changing its trajectory.
• In this experiment, the results consistently change. This is the so-called breaking ball.
• The knuckleball in baseball and the no-spin shot in soccer use this principle to cause random changes in the flow path.
• Batters and goalkeepers react to the initial direction of the path of a ball. However, if the ball changes its direction in flight, they may be taken by surprise.
• When the ball is rotating, vortex separation will be consistent, and the resulting forces will be consistent as well.

[Keywords]	separation vortices
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[Reference]	"The Wonders of Flow," Japan Society of Mechanical Engineering, Koudansha Blue Backs, pp. 174-179 "Illustrated Fluid Dynamics Trivia," by Ryozo Ishiwata, Natsume Publishing, pp. 96-97 and 198-199