WEBVTT - BrainStuff Classics: Why Do Balloons Stick To Our Hair?

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<v Speaker 1>Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,

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<v Speaker 1>I'm Lauren Vogelbaum, and this is another classic episode from

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<v Speaker 1>our previous host, Christian Sager. For me, one of the

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<v Speaker 1>weirdly comforting things about science is that it always leaves

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<v Speaker 1>itself open to further questioning and exploration. You can almost

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<v Speaker 1>always dig deeper. And that's the case with today's question,

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<v Speaker 1>why do balloons stick to our hair? Hey, brain Stuff?

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<v Speaker 1>Is Christian Sager here. When you were a kid, did

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<v Speaker 1>you ever rub a balloon really fast against your hair

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<v Speaker 1>to make it stick? What about as an adult? Well,

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<v Speaker 1>after many years of speculation, Case Western Reserve University scientists

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<v Speaker 1>have pinpointed exactly why this party trick happens. We've known

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<v Speaker 1>forever that when two objects are rubbed against each other

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<v Speaker 1>there's a build up of an electrical charge called static

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<v Speaker 1>electricity or tribo electric charging. If the two objects have

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<v Speaker 1>opposite charges positive and negative, they'll stick together. But some

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<v Speaker 1>objects appear to charge more or stick more closely together

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<v Speaker 1>than others, like the balloon on your hair. Now, why

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<v Speaker 1>is that? According to a new study published in the

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<v Speaker 1>journal Physical Review Materials, the crux of the phenomenon lies

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<v Speaker 1>and how strained the balloon material is. For the purpose

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<v Speaker 1>of this study, the scientists stretched a film of polytetrafluoroethylene.

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<v Speaker 1>Let's just call it PTFE for now. That's one of

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<v Speaker 1>the brand names for Teflon. They took that and they

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<v Speaker 1>rubbed it against a film of unstrained unstretched ptf E,

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<v Speaker 1>and they found that even though the materials were chemically identical,

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<v Speaker 1>they generated charge transfer in one direction as if they

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<v Speaker 1>had two different chemical compositions. The stretched or strange sheet

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<v Speaker 1>carried the positive charge, while the unstranged sheet carried a

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<v Speaker 1>negative charge. The more strained the material was, the more

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<v Speaker 1>likely it was to experience systematic charge transfer. This is

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<v Speaker 1>because the micro structure of the material was altered when strained,

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<v Speaker 1>leading to tiny holes and cracks. These imperfections allowed the

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<v Speaker 1>rubbing induced friction to facilitate charge transfer, leading to static electricity.

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<v Speaker 1>In a press release, co authored Dan Lax explained that

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<v Speaker 1>they think the void regions and the fibrils these are

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<v Speaker 1>tiny cell fibers. They think that those were strained when

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<v Speaker 1>the polymer had different bonding and thus a charge that

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<v Speaker 1>was different. The researchers also examined the phenomenon using packing

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<v Speaker 1>peanuts which just love to stick to people's arms. In fact,

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<v Speaker 1>polystyrene peanuts and plastic bags are currently being closely examined

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<v Speaker 1>to give us a better understanding of static electricity. Ideally,

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<v Speaker 1>scientists will nail it down so precisely that they will

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<v Speaker 1>be able to control it, helping to prevent tribe electric

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<v Speaker 1>explosions such as explosions of cold dust in minds, and

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<v Speaker 1>develop more effective products, for example, pesticides that will stick

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<v Speaker 1>better to plants or paints that will stick better to cars.

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<v Speaker 1>It may not seem that dangerous, but in fact static

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<v Speaker 1>electricity can ignite fuel vapors at the gas pump, causing fire.

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<v Speaker 1>To avoid such a catastrophe, try not to get back

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<v Speaker 1>in the car after you start the fueling process, because

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<v Speaker 1>sliding across the seat generates static electricity. If you must

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<v Speaker 1>re enter your vehicle, be sure to ground yourself first

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<v Speaker 1>when you get back out by touching the metal part

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<v Speaker 1>of your car door. Today's episode was written by Lee A.

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<v Speaker 1>Hooint and produced by Dylan Fagan and Tyler Clang. For

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<v Speaker 1>more on this and lots of other topics, visit how

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<v Speaker 1>stuff works dot com. Brain Stuff is production of iHeart

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