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Physics & Chemistry

Physics for Pitchers

Tags: Physics and Chemistry , Physics , Sports

» More stories in Physics & Chemistry

 

Story written by:

Vince Beiser

Why Does a Curveball Curve?

What makes a curveball curve and a slider slide? Basic aerodynamics, as manipulated by a skillful pitcher.

Three forces act on a spinning baseball as it flies toward the plate: the downward pull of gravity, the slowing drag of air resistance, and a "lift" force, also known as the Magnus force, caused by the direction of the ball's spin. That final ingredient is the one a pitcher can control.

The spin deflects the flow of air pressure acting on the ball to make it fall more or less slowly or curve to one side. Your basic fastball is launched with backspin; that increases air pressure beneath the ball, making the Magnus force point upward, causing the ball to fall less quickly than it would if only gravity were pulling on it. Curveballs have topspin, which makes them fall faster than they otherwise would. Sliders are spun sideways so that they break to the left or right.

Then there's the much-discussed gyroball, allegedly the specialty of Red Sox pitcher Daisuke Matsuzaka. By turning his wrist away from his body, a pitcher can send the ball spinning not in the same direction it's traveling, but perpendicular to it, like a football or a rifle bullet. That means the air pressure above and below the ball are essentially the same. The result is a sneaky pitch that looks like a fastball as it leaves the pitcher's hand, but drops faster - hopefully leaving a confused batter swinging at the air.

The faster the ball is traveling and spinning, the greater the effect of the Magnus force will be. Greater air density also increases its effect - which makes higher-altitude, thinner-air cities a tougher place to fake out a batter. So if the Rockies are having a tough year, they've always got an excuse.

CommentsComments

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10.17.07 5:43 PM PDT

bla bla

i cant reed this it is way to small of print but i love ur program it is asomeous :)

10.17.07 6:01 PM PDT

Carol Bernstein

Comment is offered as a PBS member and devoted fan

Is Wired intended to be adult or child oriented. The material is interesting but there is a childish tonality that is a bit off-putting to this adult.

Offered Spoken as a member and PBS devotee

10.17.07 6:20 PM PDT

Cam McAllister

I think that Wired Sceince is really good and I am a 8th grader and my teacher is giving it to us for extra credit. When I watch it is very cool even though sometimes it does not make sense.

10.17.07 8:51 PM PDT

Cheryl Capehart

I love the series! Its great for adults and young adults.

10.18.07 10:32 AM PDT

bd

What about the dance the Knuckleball performs and what role do the stiches play in all of these pitches?

10.18.07 5:24 PM PDT

pdk

1) I loved the ball buster feature.
2) bla bla: most browsers have a feature to increase font size, I type contol and + keys at the same time...
3) Carol: i think its for all ages, i am not put off as an adult
4) I would like to see an analysis of the effect of humidity on ball liveliness, all the ball parks have humidors now, are they really necessary?

10.21.07 11:25 AM PDT

Engineer

I find it interesting but lacking in substance.

It would be great to add some basic math with your video to make it even more educational. The baseball video lends itself well for some math since you had the Professor there.

This would help the young engineer/sport person to get more interested in what we lack more engineers and scientists in industry.

1.23.08 10:32 AM PST

samuel

great info

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