Bill Hammack, aka The Engineer Guy, is an amazing engineering educator and in this video he explains how duct tape is designed to simultaneously do three things well: “a) adhere with light pressure, b) stay in place, yet c) be removable”.Controlling the stickiness of tape is of utmost importance. In fact, a key element of engineering tape is controlling its stickiness — and only by doing that can tape be wound into a useful roll. If the tape sticks too tightly to itself, we could not use it.Gotta be honest: I was not expecting Silly Putty to make a relevant guest appearance during his explanation. And I love the ramp & ball test for tape stickiness near the end…a very elegant and simple bit of engineering:Pressure sensitive tape predates much of the most elementary molecular understanding of adhesion; tape has been mass produced since the early twentieth century. That engineers developed and refined tape without this knowledge is no surprise — recall that the purpose of the engineering method is to solve problems before we have full scientific knowledge. Tags: Bill Hammack · design · engineering · science · video