Welcome to brain Stuff from How Stuff Works. Are you there, brain Stuff, It's me Christian Seger. Do you ever think about how, with wireless internet floating around us, that we're all just waiting through gigabytes of HTML, MP three's, JPEG's, first person shooters and entire podcasts like this one. Even if you don't have a router and you avoid the library and your local coffee shop, WiFi is everywhere, So your next question might be whether all that WiFi is
safe or not? What is it and how does it affect a human body? Well, first, the term WiFi just means a wireless network, not wireless fidelity. That is a common misconception. These wireless networks translate data into radio signals and then transmit and receive those signals via antennas, So WiFi is made of radio waves. These are part of the broad range of frequency these that make up the
electromagnetic spectrum. We know that some radiation on that spectrum, like gamma rays, X rays, or high frequency ultraviolet light, can be dangerous. These waves are known as ionizing radiation. They're so high an energy that they can break apart atoms and damage our DNA. But the non ionizing wavelengths are too low in energy to ionize atoms or molecules. Since radio waves likewifi are non ionizing, they tend to be safe. The intensity of a WiFi signal is rather low.
WiFi is most often transmitted at a frequency of two point four giga hurts, about the same as most microwave ovens. For comparison, a light bulb amidst non ionizing radiation up to four hundred nanometers, which converts to hold on a second seven eight one giga hurts. That makes light bulbs
over sixty two thousand times strong longer than WiFi. Wireless network routers also broadcast further distances than microwave ovens, which is important because every time you double the distance of a radio wave, you only get a quarter of its energy. That is called the inverse square law of physics, which means Wifi's intensity drops off sharply the further you get
from a device emitting it. If you're still wondering why microwave ovens cook food, but your WiFi router doesn't consider a microwave ovens walls they're specifically designed to reflect microwave radiation in very particular directions. That creates interference between the waves that results in standing waves which oscillate in place in particular parts of the microwave. That's why sometimes your
frozen dinner doesn't cook uniformly, especially without a turntable. Now, despite WiFi being broadcast at this safe frequency, there are some controversial health concerns associated with the radiation it emits, and while there is no definitive link, the World Health Organization also known as WHO, does recognize that some studies show preliminary connections between these types of radiation and human illness. They categorize it as a class to be carcinogen, something
possibly carcinogenic in humans at given exposures. Cell phones in particular have been scrutinized. Some disputed studies have also argued that children are more at risk from devices that radiate radio waves or microwaves, or that electromagnetic radiation is a risk factor for cancer. In twleven, WHO also classified mobile phones as possibly carcinogenic, but to date there still isn't strong evidence, especially because it's difficult to prove a link
between long term tumor development and radio frequency exposure. Scientists continue to do research in this area, but your actual wireless Internet connection does not seem to be harmful, and if you're still concerned, your other option is to wrap yourself up in aluminum foil to keep a few of these frequencies at bay. No, really, I'm not kidding. Aluminum
foil creates a Faraday cage which disrupts electromagnetic sickness. Check out the brainstuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.