popular science

66 POPULAR SCIENCE

by Bryan Gardiner / photograph by The Voorhes FOR ANOTHER (ACTUAL-SIZE) SMALL WONDER, SEE PAGE 76

The Romans, Greeks, Celts, and Chinese all independently devised uses for these

friction- reducing mechanisms as far back as 900 BC. As did Leonardo da Vinci during

the Renaissance (see: helicopter drawings). The irst modern incarnation of ball bear-

ings—a 1794 patent that showed how small orbs could spin in grooves between an axle

and wheel—was meant to make it easier for horses to pull a carriage. Seventy-ive years

later, a Parisian bike mechanic placed them in the hub of a vélocipede, helping a rider

win one of the world’s irst bicycle road races. Nearly every contemporary rotating

machine relies on bearings to reduce rubbing and keep things rolling: They allow hard

drives to spin disks, help the Mars rovers steer, and, yes, let your idget spinner whirl.

ITEM:

Bearing ball

INVENTED:

1794

USE:

Rolling objects