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Speaker 1: Welcome to brain Stuff from How Stuff Works. Are you there,

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Speaker 1: brain Stuff, It's me Christian Seger. Do you ever think

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Speaker 1: about how, with wireless internet floating around us, that we're

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Speaker 1: all just waiting through gigabytes of HTML, MP three's, JPEG's,

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Speaker 1: first person shooters and entire podcasts like this one. Even

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Speaker 1: if you don't have a router and you avoid the

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Speaker 1: library and your local coffee shop, WiFi is everywhere, So

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Speaker 1: your next question might be whether all that WiFi is

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Speaker 1: safe or not? What is it and how does it

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Speaker 1: affect a human body? Well, first, the term WiFi just

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Speaker 1: means a wireless network, not wireless fidelity. That is a

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Speaker 1: common misconception. These wireless networks translate data into radio signals

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Speaker 1: and then transmit and receive those signals via antennas, So

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Speaker 1: WiFi is made of radio waves. These are part of

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Speaker 1: the broad range of frequency these that make up the

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Speaker 1: electromagnetic spectrum. We know that some radiation on that spectrum,

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Speaker 1: like gamma rays, X rays, or high frequency ultraviolet light,

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Speaker 1: can be dangerous. These waves are known as ionizing radiation.

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Speaker 1: They're so high an energy that they can break apart

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Speaker 1: atoms and damage our DNA. But the non ionizing wavelengths

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Speaker 1: are too low in energy to ionize atoms or molecules.

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Speaker 1: Since radio waves likewifi are non ionizing, they tend to

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Speaker 1: be safe. The intensity of a WiFi signal is rather low.

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Speaker 1: WiFi is most often transmitted at a frequency of two

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Speaker 1: point four giga hurts, about the same as most microwave ovens.

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Speaker 1: For comparison, a light bulb amidst non ionizing radiation up

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Speaker 1: to four hundred nanometers, which converts to hold on a

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Speaker 1: second seven eight one giga hurts. That makes light bulbs

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Speaker 1: over sixty two thousand times strong longer than WiFi. Wireless

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Speaker 1: network routers also broadcast further distances than microwave ovens, which

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Speaker 1: is important because every time you double the distance of

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Speaker 1: a radio wave, you only get a quarter of its energy.

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Speaker 1: That is called the inverse square law of physics, which

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Speaker 1: means Wifi's intensity drops off sharply the further you get

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Speaker 1: from a device emitting it. If you're still wondering why

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Speaker 1: microwave ovens cook food, but your WiFi router doesn't consider

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Speaker 1: a microwave ovens walls they're specifically designed to reflect microwave

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Speaker 1: radiation in very particular directions. That creates interference between the

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Speaker 1: waves that results in standing waves which oscillate in place

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Speaker 1: in particular parts of the microwave. That's why sometimes your

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Speaker 1: frozen dinner doesn't cook uniformly, especially without a turntable. Now,

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Speaker 1: despite WiFi being broadcast at this safe frequency, there are

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Speaker 1: some controversial health concerns associated with the radiation it emits,

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Speaker 1: and while there is no definitive link, the World Health

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Speaker 1: Organization also known as WHO, does recognize that some studies

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Speaker 1: show preliminary connections between these types of radiation and human illness.

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Speaker 1: They categorize it as a class to be carcinogen, something

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Speaker 1: possibly carcinogenic in humans at given exposures. Cell phones in

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Speaker 1: particular have been scrutinized. Some disputed studies have also argued

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Speaker 1: that children are more at risk from devices that radiate

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Speaker 1: radio waves or microwaves, or that electromagnetic radiation is a

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Speaker 1: risk factor for cancer. In twleven, WHO also classified mobile

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Speaker 1: phones as possibly carcinogenic, but to date there still isn't

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Speaker 1: strong evidence, especially because it's difficult to prove a link

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Speaker 1: between long term tumor development and radio frequency exposure. Scientists

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Speaker 1: continue to do research in this area, but your actual

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Speaker 1: wireless Internet connection does not seem to be harmful, and

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Speaker 1: if you're still concerned, your other option is to wrap

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Speaker 1: yourself up in aluminum foil to keep a few of

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Speaker 1: these frequencies at bay. No, really, I'm not kidding. Aluminum

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Speaker 1: foil creates a Faraday cage which disrupts electromagnetic sickness. Check

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Speaker 1: out the brainstuff channel on YouTube, and for more on

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Speaker 1: this and thousands of other topics, visit how stuff works

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Speaker 1: dot com.