This huge Rolling Ball Sculpture was built for a science center in Denmark in 2014. Named “The Energy Machine,” it was designed to demonstrate as many different physics principles as I could pack into one RBS.

Instead of an electric motor, the large angled helical lift is powered by the person using the sculpture. Turn the handle and the lift carries the balls back to the top. Because people can keep cranking and sending more balls into the sculpture, I had to design the tracks and elements to handle several balls at the same time without jamming. Energy in, energy out—your work lifting the balls gets turned into motion as gravity brings them back down.

This was a big one: about 6 feet high, 6 feet wide and 6 feet deep. I built outriggers into the frame so the science center could enclose it with glass or Plexiglas after installation. Having that much room to work with also meant I could really fill it with tracks and mechanisms.

The hand-powered helical lift was probably the biggest challenge of the build. I machined and installed the gears and bearings for a 5:1 ratio, so five turns of the handle produced one revolution of the lift. That kept the number of balls entering the sculpture under some control—even with an enthusiastic kid at the crank.

The sculpture runs on 1-1/2" miniature billiard balls.

100% stainless steel, TIG welded.