Nuts and Bolts

September 4, 2023
In this wide-ranging history, structural engineer Agrawal (Built) surveys how seven objects—the nail, wheel, spring, magnet, lens, string, and pump—transformed the world. Arguing that these “foundational innovations” prove “how engineering at its most fundamental is inextricably linked to your everyday life,” Agrawal discusses how the first bronze nails, dating to 3400 BCE Egypt, and their derivatives (rivets, screws, bolts) “enabled robust connections between different materials,” an innovation so fundamental it allowed for the construction of more complex buildings and boats and today makes possible such diverse gadgetry as satellites and watches. She traces the history of each invention, noting that the first known wheels were used to make pottery in Mesopotamia around 3900 BCE before they were attached to wagons for transportation several hundred years later. The straightforward prose makes it easy to understand how such contraptions as the Piezoelectric air pump work, and Agrawal has a knack for showing how simple objects provide the bedrock for intricate technologies; for example, she explains how the spring, which “tightened up and stored energy,” made possible the construction of clocks significantly smaller than previous models used in church towers, which utilized a weighted system that relied on gravity to power the gears. The result is a potent look at the building blocks of the modern world.