What do binder clips, ballpoint pens, tape measures, can openers and large bridges (like the Navajo Bridge in northern Arizona) have in common? They are all part of the invisible world of forces that impact our daily lives, and they are discussed in Henry Petroski's Force: What It Means to Push and Pull, Slip and Grip, Start and Stop (2022).
Force examines a host of scientific, physical, and mathematical topics without burying us in technical jargon. Petrosky mixes anecdotes about his life extending back to his childhood playing with the Tricky Dog dog magnet (Chapter 2 - Magnetism) or in Chapter 13 when he reminisces about watching a clerk in a bakery slice a loaf of bread and then flawlessly place it inside a plastic bag (pg. 164). He writes:
"The clearance between the contents and container appeared to be as tight as a piston in a cylinder. She left the bag open, lest the fresh bread be crushed in the course of closing it. She did not have to be so careful with a loaf of rye bread because its crust gave it both stiffness and strength to resist. Watching the whole seamless process and imagining the forces involved was to me the greatest thing since sliced bread itself."
Reading Force will change how one looks at some of the simplest objects like the binder clip and ballpoint pen (Chapter 12 - Stretching and Squeezing), the can opener (Chapter 6, - Lever, Lever, Cantilever), and the tape measure (Chapter 14 - Deployable Structures). You will even feel a little better about yourself when you learn that your fingerprints wear thinner and lose some of their tactile qualities, which explains why I drop more objects (like pens, clips, and tape measures) than I used to.
This doesn't mean that Petrosky doesn't tackle bigger engineering feats like bridges, arches and domes, and obelisks. As he describes the reasons behind famous bridge collapses you may be thankful that bridge repair is part of the Federal infrastructure plan.
