A Brief History of Timekeeping | How Humans Began Telling Time | EXPLORE MODE

a lot happens in 24 hours your heart beats around 100,000 times 150 to 200 species of animals become extinct lightning strikes earth 8.6 million times astronauts aboard the International Space Station will see 16 sunrises and 16 sunsets about three and fifty thousand two hundred babies will be born and about one hundred and fifty one thousand six hundred people will die so yeah a lot goes on in just 24 hours but why is a day divided in twenty four hours in the first place who decided how we would calculate it today time is tucked away in our pockets just an unlock button away it drives our technology with atomic clocks being responsible for precise GPS location services and speedy internet search results our ancestors on the other hand didn't have it that easy time for them was written in the stars in the sunrise and sunset and the moon's waning and waxing so how did we go from looking up to celestial bodies to looking down at our phones for time what other timekeeping methods did ancient humans used before watches and clocks became ubiquitous and what the heck is an atomic clock you're watching explore mode and today we're diving into time and how humans develop technologies to measure it let's start with celestial bodies early civilizations like the Egyptians use the moon's phases to determine the length of a month in prehistoric Europe humans built stone rings called recumbents stone circles that would frame and track the moon in each of its phases it's believed they were built for ritualistic purposes then we have the creation of the sundial the device that shows the time using the sun's shadow depending on its position in the sky the earliest archaeological evidence of a sundial was found in the valley of Kings in Upper Egypt in 2013 and it dates back to 1500 BCE a larger version of the sundial is the obelisk which was used to mark the summer and winter solstices while Egyptians Romans and Greeks were using sundials to keep track of time people in Asia were using candles and incense sticks candle clocks worked as follows each candle had markings on its sides indicating the passage of a certain period of time so as the candle burned you could calculate how much time had expired the first reference to candle clock states back to 520 ad in a poem written by Chinese thinker yeo jingoo who seemed to use them for study sessions similar to candle clocks early evidence of incense clocks takes us back to China 6th century China to be exact different incense sticks would indicate the passing of time depending on how quickly they burned some snakes had different aromas for each hour that passed and others had weights attached at different sections that would drop as the incense burned but incense clocks stuck around well after we had developed watches and pendulum clocks until 1924 in Japan geishas would count how many incense clocks had been burned during their services to charge their customers Egyptians divided their Sun dials into twelve parts for each hour of the day from dusk to dawn although Sun dials were quite accurate for their time they had one very evident disadvantage they were practically useless during overcast days and at night but back to the 12th hour day division so twelve hours for daytime twelve hours with a night time of twenty-four hours a day no surprise there but why that is each hour divided into 60 minutes and each minute into 60 seconds well that has to do with a numerical system that is still used today time for an express explore explanation start the clock the sexagesimal system takes us back to ancient Mesopotamia it is a numerical system based on the number 60 that was developed by the Sumerians and later adopted by the Babylonians they developed it by dividing parts of their fingers into single units and units of 12 here's how it worked and take a look at the palm of your hands notice that each of your fingers is divided into three sections using their thumbs to count the Babylonians realized they could count up to 12 for each section on finger of one hand three times four equals twelve the five fingers on the other hand each represented a dozen so twelve times five equals sixty also sixty is divisible by 1 2 3 4 5 6 10 12 15 20 and 30 making it an easy number to split for a civilization with no calculators this system is used nowadays to divide time angles geographical coordinates and it is the mathematical base for astronomical coordinate systems in order to bypass the no sunlight conundrum the Egyptians needed another method of timekeeping and so they developed the water clock here's how they worked Egyptians would fill a bowl shaped container with water said water had a spout at the bottom which would allow for water to flow out into another container it had 12 markings on the inside each line representing the passing of an hour as the water flowed out they would compare the water level with the markings to determine how much time had passed the problem with this type of water clock was that it didn't provide an accurate representation of the passage of time you see as a container empty out the pressure of the water would lessen making it run more slowly by the end entered to savea's an inventor and mathematician from Alexandria and the man now regarded as the inventor of the first real clock between 270 BC and 500 AD he figured that instead of measuring time based on the outflow of water he would measure the consistent inflow of it it worked pretty much in the same way except that instead of measuring how much a container had emptied he would measure the rise of the water level as the liquid steadily flowed into the container unbeknownst to decipi us he had created the first I'll be at quite rudimentary mechanical clock for many years the perfect did water clock was the most accurate timekeeping device that is until proper mechanical clocks appeared the first people to build large mechanical clocks with Catholic monks they needed precise timekeeping devices to schedule chores and prayers within the monastery according to historian Thomas woods the first recorded clock was built by the future pope sylvester ii for the german town of Magdeburg around the year 996 then came the inventions of Christian Huygens a Dutch physicist mathematician astronomer and inventor who using theories from none other than Galileo Galilei created the technology behind the pendulum clock and the springs in the pocket watch pocket watches were the first to be mass-produced allowing everyone and their mother to be able to keep time in their pockets clocks today are more precise than they have ever been seconds are no longer measured with the swing of a pendulum they are measured with crystals and atomic particles time for an express explore explanation start the clock with pendulum clocks one swing of the pendulum equates to one second this is how you calculate a time but pendulums depend on a lot of external factors to maintain a constant swing so a more precise form of frequency was needed to create more accurate clocks that's where the quartz comes in check your wristwatch or whatever timepiece you own if it says quartz it means that your device is powered by a crystal the quartz is a clear mineral made of silicon and oxygen that vibrates at a very precise frequency whenever it is zapped with electricity quartz crystals are fashioned into resonators in the shape of a tuning fork and put inside timepieces where they're receiving constant electric signals a piece of quartz resonates at 32,768 pulses per second indicating that whenever the quartz reach that amount of pulses a second had passed but although quartz clocks are fairly accurate there's still not the most precise form of timekeeping quartz crystals vibrate at different frequencies depending on whether they're in warm or cool environments making them gain or lose few seconds what can be more precise than the oscillation of a crystal being electrocuted atoms caesium 133 atoms to be precise see cesium atoms resonate between different energy states at an extremely stable frequency a quality that is imperative for precise timekeeping so in 1967 the National Institute of Standards and Technology declared that the official measurement of a second is equivalent to [Music] 9,192,631,770 oscillations of a cesium atoms resonant frequency and that is still the standard use today timekeeping devices nowadays not only help us determine our work schedule or set up our alarms they're an integral part of the technology we see all around us GPS satellites have at least two caesium and rubidium atomic clocks on board in order to calculate the time delay of signals and provide an accurate reading of a location in December 2018 scientists at the National Institute of Standards and Technology developed two clocks using 1,000 atoms of the element ytterbium in grids of lasers these clocks are so precise that they can show the effects of gravity on earth helping us measure the space-time continuum so far this is the most precise form of timekeeping but a new technology might emerge in the next decade or century or millennia who knows only time will tell thanks for watching explore mode if you liked this video hit the thumbs up button if you want to explore even more with us check out our playlist there's plenty to explore there before you leave make sure to hit the subscribe and bail see you next week and in the meantime keep your explore mode on

Channel: Explore Mode

Views: 141,899

Keywords: brief history of time, history of time, timekeeping, brief history of timekeeping, history of timekeeping, history of timekeeping devices, telling time, time, sundial, pendulum, galileo galilei, ctesibius, water clock, atomic watch, atomic clock, quartz clock, how do atomic clocks work, ancient egypt

Id: oSSIBM1nEsE

Length: 10min 2sec (602 seconds)

Published: Thu Sep 26 2019