Speaker 1: Welcome to brain Stuff from how Stuff Works. Hey, brain
Speaker 1: stuff is Christian Saker here. When you were a kid,
Speaker 1: did you ever rub a balloon really fast against your
Speaker 1: hair to make it stick? What about as an adult? Well,
Speaker 1: after many years of speculation, Case Western Reserve University scientists
Speaker 1: have pinpointed exactly why this party trick happens. We've known
Speaker 1: forever that when two objects are rubbed against each other,
Speaker 1: there's a build up of an electrical charge called static
Speaker 1: electricity or tribo electric charging. If the two objects have
Speaker 1: opposite charges, positive and negative, they'll stick together. But some
Speaker 1: objects appear to charge more or stick more closely together
Speaker 1: than others, like the balloon on your hair. Now, why
Speaker 1: is that? According to a new study published in the
Speaker 1: journal Physical Review Materials, the crux of the phenomenon lies
Speaker 1: and how strained the balloon material is. For the purpose
Speaker 1: of this study, the scientists stretched a film of polytetrafluoro ethylene.
Speaker 1: Let's just call it PTFE for now. That's one of
Speaker 1: the brand names for teflon. They took that and they
Speaker 1: rubbed it against a film of unstrained, unstretched ptf E,
Speaker 1: and they found that even though the materials were chemically identical.
Speaker 1: They generated charge transfer in one direction as if they
Speaker 1: had two different chemical compositions. The stretched or strange sheet
Speaker 1: carried the positive charge, while the unstrained sheet carried a
Speaker 1: negative charge. The more strained the material was, the more
Speaker 1: likely it was to experience systematic charge transfer. This is
Speaker 1: because the micro structure of the material was altered when strained,
Speaker 1: leading to tiny holes and cracks. These imperfections allowed the
Speaker 1: rubbing induced friction to facilitate charge transfer, leading to static electricity.
Speaker 1: In a pre US release, co authored Dan Lax explained
Speaker 1: that they think the void regions in the fibrils these
Speaker 1: are tiny cell fibers. They think that those were strained
Speaker 1: when the polymer had different bonding and thus a charge
Speaker 1: that was different. The researchers also examined the phenomenon using
Speaker 1: packing peanuts, which just love to stick to people's arms.
Speaker 1: In fact, polystyrene peanuts and plastic bags are currently being
Speaker 1: closely examined to give us a better understanding of static electricity. Ideally,
Speaker 1: scientists will nail it down so precisely that they will
Speaker 1: be able to control it, helping to prevent tribe electric explosions,
Speaker 1: such as explosions of coal dust in minds and develop
Speaker 1: more effective products, for example, pesticides that will stick better
Speaker 1: to plants or paints that will stick better to cars.
Speaker 1: It may not seem that dangerous, but in fact static
Speaker 1: electricity can ignite fuel vapors at the gas pump, causing fire.
Speaker 1: To avoid such a catastropheure try not to get back
Speaker 1: in the car after you start the fueling process, because
Speaker 1: sliding across the seat generates static electricity. If you must
Speaker 1: re enter your vehicle, be sure to ground yourself first
Speaker 1: when you get back out by touching the metal part
Speaker 1: of your car door. Today's episode was written by Aliya Hoyt,
Speaker 1: produced by Tristan McNeil, and For more on this and
Speaker 1: other topics, please visit us at how stuff works dot com.