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  • Some people need a little noise in the background when they're trying to get to sleep.

  • If you're me, that means putting on Futurama in an endless loop until you know every episode

  • word for word... in your sleep.

  • But if you're a normal, healthy, functioning person, you might turn on some white noise.

  • It turns out, though, there are morecolorsof noise, like pink, blue, and brown.

  • How are these colors different, and what do they do to your brain while you sleep?

  • Obviously sound has no color, unless you have synesthesia... in which case, awesome.

  • But in this case it's helpful to use colors as an analogy

  • for the spectrum of frequencies in noise.

  • White light has all the colors of the rainbow equally represented, which is why

  • it doesn't look like any one particular color.

  • Likewise, the frequencies in white noise are all equally represented, with the lowest audible

  • frequency at 20 Hz having the same power as all the frequencies above it,

  • up to the highest frequency humans can hear, at 20,000 Hz.

  • White noise sounds like this:

  • [KSSSCK]

  • There are natural sources of white noise, like steam hissing from a radiator

  • or static from a TV.

  • But if you're all modern with your gas furnace and digital TV and still can't sleep,

  • then you can buy a white noise machine.

  • Because white noise is all frequencies, it can help mask other noises,

  • like the ringing of tinnitus or the sound of your girlfriend snoring... Katie.

  • But humans don't hear all frequencies equally.

  • The distance between 30 Hz and 60 Hz sounds the same as the distance

  • between 10,000 Hz and 20,000 Hz; to us, both notes are one octave apart.

  • And we're more sensitive to high-pitched noises, like babies crying.

  • Enter pink noise.

  • Unlike white noise, the energy in pink noise is highest for the low frequencies,

  • and is halved every time the frequency doubles, meaning every octave has equal power

  • and the net effect sounds less bright, and more balanced, than white noise.

  • Here's white noise again:

  • [KSSSCK]

  • And here's pink noise:

  • [WHOOOSH]

  • While white noise is by far the most researched noise color, pink noise studies

  • are on the rise recently.

  • One from 2012 found that participants who listened to pink noise while they slept

  • showed an improvement in deep sleep, and reported sleeping better.

  • During deep sleep, the neurons in your brain are firing slowly,

  • what's known as the delta brain wave pattern.

  • As we age, we don't get as much deep sleep, which is associated with memory problems.

  • So, a 2017 study played bursts of pink noise in sync with the delta brainwave

  • to older adults, and found the waves increased in amplitude,

  • and participants performed up to 30% better on memory tests.

  • Why?

  • Well, scientists are just beginning to explore the connection between sound and neural activity,

  • but one thing's for sure -- the key to the results is timing,

  • so if you're Philip J. Fry and don't have a delta brainwave, you're out of luck.

  • That was a Futurama deep cut – y'gotta get on my level.

  • The only other color noise that has an official Federal Communications standard definition

  • is blue noise, which is like the opposite of pink noise,

  • where higher frequencies are amped up.

  • Wanna hear the most annoying sound in the world?

  • [HISSS]

  • Unofficially, there's also grey noise, where the high AND low ends are emphasized:

  • [THURSSS]

  • and Brown noise, where the frequencies mimic the randomness of Brownian motion:

  • [WISSSH]

  • Now, if you said that means the Brown noise is named after a person, not a color, you are

  • you are technically correct... which is the best kind of correct.

  • (Disappointingly, it has nothing to do with the mythical pitch that will make someone poop their pants.)

  • There are even more sounds I don't have time to touch on,

  • but it turns out there are a lot of colors of sound,

  • and they have some surprising applications and effects

  • that research is just starting to explore.

  • So if you love science, make some noise!

  • [KSSSCKWHOOOSHHISSSTHURSSSWISSSH]

  • And if you REALLY love science, you better hit that subscribe button

  • so you can catch all of our videos here on Seeker!

  • Also, be sure to check out this awesome video about scientists that sift through COSMIC noise

  • to identify alien signals.

  • Thanks for watching!

Some people need a little noise in the background when they're trying to get to sleep.

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