Galileo revisited: How ribbons roll
Galileo Galilei’s experiments on the motions of falling and rolling objects, described in his 1638 book, “Two New Sciences,” are considered by many to be the beginning of modern science. Now researchers at MIT have conducted a variation on his experiments that has produced unexpected results.Galileo used rigid materials — metal balls and a wooden ramp — for his tests on how bodies move down an inclined plane. Since then, a few tests have been done with solid balls rolling down a flexible surface. But until recently, nobody had tried rolling flexible objects down a solid plane. MIT professors Pedro Reis and John Bush, along with visiting student Pascal Raux and visiting professor Christophe Clanet, have now carried out experiments using a variety of flexible, hollow cylinders — essentially wide rubber bands — with different degrees of elasticity, and have derived a set of equations to describe the behavior of...