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Speaker 1: Welcome to brain Stuff, a production of iHeart Radio, Hey

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Speaker 1: brain Stuff Lauren Vogelbaum here. From pillows to blankets to

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Speaker 1: entire mattresses, manufacturers today offer a variety of products how

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Speaker 1: did to keep people cool? But unlike the heated versions

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Speaker 1: of these products, which have some sort of electric system inside,

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Speaker 1: cooling textiles are just that textiles. So what's the secret?

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Speaker 1: How do these products lower your body temperature without fancy technology?

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Speaker 1: And do they really work? The history of cooling fabric

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Speaker 1: goes back to the early days of NASA, when scientists

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Speaker 1: there were working on how textiles could impact someone in

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Speaker 1: a space suit. Of course, NASA now utilizes other technology

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Speaker 1: in its space suits to keep astronauts cool, including cooling

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Speaker 1: panels with liquid filled channels and a network of narrow

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Speaker 1: tubes linked to a backpack refrigeration unit. This is a

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Speaker 1: far cry from the sleek shirt shorts and other athletic

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Speaker 1: were offered by fitness gear companies. The cooling technologies that

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Speaker 1: go into these everyday textiles can be divided into three

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Speaker 1: main categories temperature balance, temperature abatement, and phase change Materials.

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Speaker 1: Fabrics that cool using temperature balance focus on wicking our

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Speaker 1: bodies already try to keep us cool by creating sweat.

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Speaker 1: When that moisture evaporates, it cools us off. These fabrics

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Speaker 1: wick away sweat and disperse it across the fabric's surface

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Speaker 1: to evaporate faster. Typically, these fabrics are treated with a

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Speaker 1: polymer that helps channel moisture. A temperature abatement, on the

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Speaker 1: other hand, works by actually transferring heat, and the textile

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Speaker 1: will feel cool to the touch, although it technically isn't

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Speaker 1: That feeling of coolness is achieved through the conductivity of

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Speaker 1: the fabric's yarn, which will usually be made of a

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Speaker 1: highly conductive polyethylene, whereas wicking technology consists of a treatment

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Speaker 1: applied to the fabric. In this case, the yarn itself

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Speaker 1: is made to cool. This yarn rapidly transfers heat away

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Speaker 1: from its surface. Think about how different wood and metal

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Speaker 1: feel to the touch. If samples of these are sitting

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Speaker 1: side by side in an air conditioned room, the metal

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Speaker 1: will feel cooler to the touch, even though the ambient

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Speaker 1: temperature is the same for both. But when the heat

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Speaker 1: of your hand is applied, some materials will, like the metal,

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Speaker 1: will transfer heat away from the surface faster, giving a

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Speaker 1: cooling sensation. The polyotylene yarn used in some cooling fabrics

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Speaker 1: can work in the same way. So a cool to

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Speaker 1: the touch blanket that incorporates a heat conductive yarn absorbs

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Speaker 1: body heat and displaces thermal energy to create a cooling effect.

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Speaker 1: In both of these cases, the cooling results from transference.

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Speaker 1: Either heat or humidity is transferred away from your body. Meanwhile,

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Speaker 1: phase change material reals can change from liquid to solid

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Speaker 1: state depending on the temperature, and so they can work

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Speaker 1: to regulate the temperature in betting. For example, these materials

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Speaker 1: liquefy when they're warm, absorbing heat and thus limiting the

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Speaker 1: temperature of the surface they're embedded in, and they solidify

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Speaker 1: when they're cool, releasing heat and raising the surface temperature.

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Speaker 1: In this way, they can maintain an ideal range of temperatures.

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Speaker 1: A small phase change material capsules are embedded into fabrics

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Speaker 1: to use this technology. So where are these different cooling

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Speaker 1: technologies used in apparel? Almost all cooling technology is dynamic wicking,

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Speaker 1: partly because those polyethylene yarns aren't as comfortable against the

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Speaker 1: skin and are more difficult to work with. But when

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Speaker 1: it comes to home textiles, all three types of cooling

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Speaker 1: products are available, So are these products really enough to

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Speaker 1: keep you cool while you're working out or sleeping through

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Speaker 1: the night. In theory, theyhould all work, but one factor

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Speaker 1: that can affect how cool you feel is how many

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Speaker 1: barriers are between you and the cooling textile, non cooling

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Speaker 1: garments or sheets between you and the cooling fabric cand

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Speaker 1: all the effect and heat can also be trapped by

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Speaker 1: any non cooling layers placed outside the cooling layer. Today's

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Speaker 1: episode is based on the article how high tech fabrics

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Speaker 1: cool you down when you heat up on how stuff

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Speaker 1: works dot Com, written by Carrie Whitney. Brainstuff is production

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Speaker 1: of by Heart Radio in partnership with how stuff works

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Speaker 1: dot Com, and it is produced by Tyler Clang and

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Speaker 1: Ramsey l. Four more podcasts my Heart Radio, visit the

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