This simple-looking Rolling Ball Sculpture was built for a very specific purpose. Rolling on the track are two different kinds of 1" balls — miniature billiard balls and steel balls. There’s only one track, and while I still wanted it to be fun to watch, the real purpose of this project was sound.

Near the bottom of the track, each ball drops several inches onto another section of track. The sculpture was commissioned by a company that made equipment for detecting changes in sound on assembly lines. Sound matches what’s normal? Good. Detect an abnormal sound? Bad. Pretty simple idea.

The miniature billiard balls and steel balls make noticeably different sounds when they hit the track, making this RBS a physical demonstration of the company’s technology for trade shows. Once they received the sculpture, they mounted their sound-detection equipment to it — that part isn’t shown here.

I was originally asked to build one of these. Apparently it worked well and looked good doing it, because they later came back and asked me to build a second one just like it.

100% stainless steel, TIG welded.