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thanks for watching techwiki click the subscribe button then enable

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notifications with the bell icon so you won't miss any future videos remember

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when every time you had a power outage you had to go through this frustration

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where you had to reset the time on your vcr and somehow no one in the house

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could figure out how to do it no no no one else remember maybe i'm just getting

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old anyway those days are mostly a memory now as gadgets like computers and

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smartphones can set the time themselves

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either because engineers thought it would be a useful feature or maybe

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because they don't trust us to adjust the clocks ourselves after setting up

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the vcr somehow became a meme like

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before the internet but how exactly do they do this let's start out by talking

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about phones which perhaps unsurprisingly receive a time signal

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from the cellular network so you can easily check to see if this feature is

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turned on here in Android and here in

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iOS however if you're using a Windows pc

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it's actually set by default to fetch the time every so often from an internet

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time server pretty straightforward sounding right

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but where exactly do these sources get their

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time frame is there like a gigantic master clock somewhere that's even

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bigger than big ben like kind of like the the linksys router for the internet

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in south park that was an old episode too boy i'm getting old surprisingly the

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answer is actually sort of most time servers and cell networks ultimately get

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their time from atomic clocks because they are incredibly accurate thanks to

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having virtually no drift for example if

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you've got a cheap quartz wrist watch and you set it accurately you can expect

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it to perhaps be off by a few seconds a month later it's not perfect but it's

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not too bad but if you're building a clock that's supposed to be the standard

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for millions of devices worldwide that just ain't going to cut it instead

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atomic clocks work by you guessed it using the properties of

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individual atoms to keep time so the us government's main pair of atomic clocks

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called nistf1 and f2 use atoms of cesium

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a metal that actually melts on a warm summer's day as their timekeeping

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mechanism these atoms get bombarded with

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microwaves which cause the electrons buzzing around these atoms to become

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excited or to change energy states if you think back to high school chemistry

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which boy was a long time ago for me and these state changes happen billions of

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times per second in fact a cesium atom will oscillate a fixed number of times

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every second this many exactly

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because every atom of pure cesium 133 is

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the same this electron jumping behavior

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is very consistent and predictable to the point where the scientific

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definition of a second isn't 1 60 of a

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minute but rather the amount of time it takes a cesium atom to oscillate this

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many times this consistency makes atomic clocks

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extremely accurate so the nist f2 clock is accurate to one second in

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300 million years so if you were to sync up your dvr to it you could still be

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confident that it will record the super bowl at the right time in a few million

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years when the nfl has finally given up on using roman numerals and the awesome

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thing is that tapping into the power of these clocks is so easy if you're using

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Windows your date and time settings actually has a spot for you to punch in

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a network time protocol or ntp server

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that will pull the time from an atomic clock or you can connect a little more

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directly to the united states atomic clock system by selecting time.nist.gov

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from the drop down menu meanwhile cellular networks often grab

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the time from gps satellites which have their own built-in atomic clocks and

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then pass them along to your phone and then if you're going somewhere where you

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won't have service you can actually even download apps that can connect your

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phone directly to the gps so that you can run on atomic time although

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obviously this would be more of a battery hog finally surprisingly even

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some traditional clocks and watches can receive special radio signals from

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stations around the world that are dedicated to just broadcasting atomic

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time but do remember that because of network latency and other types of

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overhead the time on your pc phone or watch might not match the atomic clocks

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exactly so the next time you show up 50 milliseconds late for work and your boss

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is razzing you you can just you can just blame it on bad reception speaking of

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so thanks for watching guys like dislike check out our other channels videos

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videos sorry for some reason we changed that leave a comment with a video suggestion if you have any and don't

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forget to subscribe and follow

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and the bell icon smash it smash it

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but don't destroy it we need to still work just maybe crack it yeah