What has many teeth but can't bite?

The answer to the riddle lies in a common fastening device found on everything from jackets to bags. This ingenious mechanism features two rows of precisely shaped "teeth," or elements, typically made of metal or plastic, affixed to fabric tapes. A slider, operated by hand, contains a Y-shaped channel that guides these teeth to interlock or separate. As the slider moves, it precisely meshes each hook-like element on one side with a corresponding hollow on the other, creating a secure closure. Despite this intricate arrangement of many "teeth," they lack the biological structure, muscles, or intent to bite in the way an animal would.

The journey to this ubiquitous fastener began long before its modern form. Early attempts include Elias Howe's 1851 patent for a garment fastening, though he didn't pursue it, and Whitcomb L. Judson's "Clasp Locker" of 1893, designed for shoes, which used hooks and eyes but proved unreliable. The truly practical and widely adopted design came from Swedish-American engineer Gideon Sundback, who patented his "separable fastener" in 1917, featuring the interlocking teeth we recognize today.

It was the B.F. Goodrich Company that gave the fastener its catchy name in 1923. They applied Sundback's invention to a new line of rubber boots, and an executive reportedly coined "zipper" to describe the swift "zip" sound the device made when operated. Initially used for boots and tobacco pouches, zippers quickly revolutionized clothing, especially for children, by promoting self-reliance in dressing. Today, this everyday marvel remains an indispensable part of countless items, a testament to its simple yet effective design.