FORCE

The veteran engineer and acclaimed science writer examines some basic element of physics.

Petroski, a rare engineer whose writing delights general readers, does not ignore the textbook definition of force as any action that can change the motion of an object, but he casts his net widely. He writes that force in our daily lives allows us to feel “the sensations of push and pull, weight and buoyancy, resistance and assistance, achievement and defeat….Without forces and their effects we would lose contact with the world.” Stretching that point, he adds that the intangible forces of “charisma, persuasion, and influence” can enable someone to create positive social or political movements or reverse them. Petroski concentrates on the science but also includes sizable doses of history and memoir. Surprisingly, we deal with only two forces in our daily lives. That gravity is universal seems reasonable, but readers may be startled to learn that this is literally true: Zero gravity does not exist anywhere. Space station astronauts seem weightless because the gravity pulling them down is counteracted by the centrifugal force of their orbital speed around the Earth. Magnetism is local and often seemingly supernatural. Petroski illustrates this concept through amusing accounts of his childhood toys and the history of the telephone, which, over 150 years, has evolved from a heavy box attached to a wall to a tiny, vastly more complex device that fits in a pocket. Having written The Pencil, The Toothpick, The Evolution of Useful Things, and The House With Sixteen Handmade Doors, Petroski has no trouble delivering an engineer’s view of dozens of tools, structures, containers, and modes of transportation. He’s also insightful in his discussions of everyday actions such as shopping and measuring. Petroski pays special attention to bridges and skyscrapers because lack of attention to forces acting on them can lead to alarming consequences.

Another gem from a master of technology writing.