How Scientists Proved That A Curve Ball Curves

It's not just an illusion

Major League Baseball's All-Star Game is happening tonight, so it's clearly time for some more baseball science.

The National Institute of Standards and Technology (NIST) just released a video (watch it at the top of this post) about how researchers in the 1950's figured out that a curve ball really does curve. That might seem obvious to us, but back then, before the benefit of instant replays or HD TVs, some people thought that it might just be an optical illusion.

Back in 1959, Lyman Briggs, a baseball fan and former head of the NIST, proved that not only did a curve ball curve, its curve was related to the spin of the ball. Figuring this out took a lot of experimenting, and at least one broken window.

Two years ago a visitor to the industrial building at NBS, listening to a serious discussion of a mechanical problem by a young scientist, was startled by a lound [sic] bang a few feet in back of him. It turned out to be Dr. Briggs shooting baseballs at a paper target 60 feet away, using a large mounted air gun. In these experiments, a baseball was rotated on a rubber tee, to give it spin, and was struck by a wooden projectile shot from the gun. The projectile drove the ball to the target. (In one wild shot, by the way, the projectile broke a window.) Dr. Briggs tried photographing the ball in flight from above. This gave him the speed and the curve, but it was impossible to mark the ball so as to measure the spin. Since spin was so important, he moved his experiments to the NBS wind tunnel, where speed and spin could be directly measured.

- Department of Commerce Press Release, 1959

Briggs published a paper detailing his research in 1959, and we covered it in Popular Science that same year. It wasn't the first time we wrote about the physics of curveballs. Another set of articles (and a scholarship contest) about the curve of a curveball were published in Popular Science in 1920. At the time, the best explanation for the curve was "simply a matter of atmospheric pressure".

Some things have changed since 1959 (and 1920, for that matter). In our 1959 article, we noted that the fastest recorded pitch was 98.6 miles per hour. Today, MLB pitchers regularly throw pitches in excess of 100 miles per hour.

The times they are a changin'. But the basic science that Briggs studied in 1959 remains the same. Even so, research into curve balls is still continuing. In 2013, researchers created a computer model of pitcher Adam Wainwright's curveball.

Look through our articles from1959 and 1920 below.

1959 Article
Page 1 of the 1959 curve ball article.Popular Science
1959 Article
Page 2 of the 1959 curve ball article.Popular Science
1959 Article
Page 3 of the 1959 curve ball article.Popular Science
1920 Article
DIY experiment 1920's style.Popular Science
1920 Scholarship Essay

1920 Scholarship Essay

Reading comprehension essay contest.Popular Science