Why Do We Use 12 Instead Of 0 On The Clock?

Clocks have been around for quite a while and they have been a very big part of our lives for quite a few past centuries now. The Analog clock that we are so comfortable with was first made in 1656 by Christiaan Huygens, but that clock too had a 12-hour time-frame which raises the question that where does this 12-hour phenomenon derives itself from and Why Do We Use 12 Instead Of 0 On The Clock? And that is exactly what we will be answering in this article, so without further ado, let’s dive right into it

It goes back to the ancient Sumerian/Babylonian base 60 number system. They didn’t have the number zero back then. And hence it was ultimately decided to settle on 60 after some extensive discussions and calculations by the mathematicians of the time. As 60 easily breaks into 2 lots of 30, 3 lots of 20, 12 lots of 5, 4 lots of 15, 2 lots of 15 lots of 2, and so on

This decision proved quite helpful for them in conducting their daily trade as people of the time weren’t mostly educated to deal with fractions and this proved quite helpful. This was precisely the same reason for why 360 degrees were chosen.

So simply put 60 minutes in an hour and 12 blocks of time that we regard as an hour in a day and 12 at night was quite convenient and basically is a throwback to the Babylonian system that gave birth to this very concept.

Down below is a video showing how counting in 12s can be quite helpful

Another quite important point to add here is that zero hadn’t been invented by the time when we as a species first started recording and scheduling time, so it had already become a norm to never use and include anything of the sort, so some might say that zero was a bit too late to be included in the clock, even though it was discovered way before the invention of12 hour clocks but humanity already been scheduling their time without anything called zero

The 12-hour clock can be first traced back to Mesopotamia and Ancient Egypt. Both an Egyptian sundial for daytime use and an Egyptian water clock ( which we will talk about in detail later in this article ) for night-time use were found in the tomb of Pharaoh Amenhotep I. Dating to c. 1500 BC, and even this clock was divided into 12 respective hours. And it didn’t take long for the concept to travel around the world as people traveled and learned and shared

The Astrophysicists

Moreover, even the Romans used a 12-hour clock: daylight was divided into 12 equal hours and then the night was divided into four watches. So the very base of it all started due to the very initial separation of day and night into segments of 12 hours for the convenience and that as we said is what we still carry on from our ancestors

Moreover, the astrophysicist and enthusiast of the time were thinking and theorizing on the movement and revolution of the day and it being complete in nearly 24 hours, though they weren’t sure yet, the concept itself was put out there. And as more and more people got to know about this, it only made sense to divide the day in 2 equal proportions of 12

Why Are Clocks Round In Shape?

The Circular shape is considered linear and is in line with the motion of the hands, as they too have to move in a circular motion ( keeping the same distance from everywhere on the clock. Moreover, as we know the initial clocks humanity made weren’t round not even close. As it was never even a concern to consider the shape of the clock.

As their sole function was and still is to tell time and that is not affected by its shape whatsoever. Some experts do say that the initial shape was decided to be circular because of its symmetry and the overall happy and soothing shape in itself portrays, and some even say that it promotes a lighter mood. On the other hand, others say that there wasn’t any special reason for the clocks to be made this way other then it is not being sharp and just being a bit more convenient.

Lastly, as time has progressed, another reason has merged and that is familiarity & habit, as most of the people out there have grown up with a round clock hanging on the wall. It just subconsciously has become a part of what we call home

Some clocks in the Past ( The Clock’s evolution )

A Water Clock

One fo the very first devices used to measure time was the water clock back in the 5th century B.C. To elaborate, some amount of water was put in a vessel. That was allowed to escape through a hole in the bottom. The time determined varied according to the size of the vessel and the hole made at the bottom

A picture of an ancient water clock to better answer "Why Do We Use 12 Instead Of 0 On The Clock?

It was all before we had the liberty of wearing fancy clocks on our wrist. Or even the scientific knowledge to make the atomic clock. Which helps function the internet as well as the GPS system properly. So, how was it possible for anyone to maintain some kind of a schedule. And then sundials were made which made it possible to navigate through time but they only worked in the day time. So, Egyptians thought of making a time measurement device using the most common liquid around, water. They were educated enough to know that as the level of water in a container drops, the outflow of the stream coming out of the hole made will also drop

A picture of different flows of water to better answer "Why Do We Use 12 Instead Of 0 On The Clock?
What is a water clock And how does it work?

History of waterclocks

Egyptians started off by using the water clock as more of a timer than a clock. It started off being used in the Egyptian courtrooms where a lawyer would be allowed one bucket of water to let him know of the time he has left whilst presented his case. Moreover, in order to account for interruptions and or breaks, they would simply close the whole with a whole.

An advancement in this way of water clock was seen in the Jarasandh period of Korean history. Engineers of this time took advantage of the buoyancy force,( the upthrust force that the water applies on any object when it is immersed into the water) to develop an alarming system. They already knew through the teachings of Archemdis. That the buoyant/upthrust acting on the body could cause the body to float depending on the density of the object.

So, they build another mechanism, where the runoff water fills the secondary vessel object. An object with a lower density is placed in the second vessel. Which will float and come up as the water is filled in the second container.


They were one of the first instruments to be used for dividing up a day. It was used to divide up the day from sunrise to sunset to 12 equal parts. But, as the name tells, this clock was only useful in the day time

It used the shadow of an object exposed to the sun. And, as the sun went through its progressions throughout the day, it ultimately caused the shadow of the object to move and ultimately tell time

A picture of a sundial to better elaborate Why Do We Use 12 Instead Of 0 On The Clock?

The sundial is considered the very first device that was used by the ancient people to figure out the time. The world’s oldest sundial is the “valley of king” which dates back to 1500 B.c. but some say that the history of sundials started way before that. There were different types of sundials that were used. Some made of stones and other made of wood

The Candle clocks

This came to be in China in near 500 A.D. An example of how it worked is that as the candle burnt down whilst the passing of the day the time would be determined by seeing how much the candle has already burnt and which mark it has crossed. To further elaborate, here is a picture

 A picture of the candle clock

Then came the mechanical clocks in the 14th century which soon became the standard. It started off by having a weight hanging from a pulley that turned the geared the single hand. Which indicated the hours as well as the portions of the hour. Then came the spring-wound clocks in the fifteenth century. This was around 1400 A.D. when coiled springs began to be used in clocks. And as most of the locksmiths were also clockmaker, hence they were simultaneously introduced in clocks too.

The sand Glass

Probably, the most famous of ancient clocks and there is a high chance you have at least seen it. The sandglass consists of two glass bulbs which are vertically connected with a narrow neck. The neck allows some amount of sand to pass through the upper glass to the lower glass. Usually, the upper and lower glasses are exactly alike, so the sandglass would measure the exact same time regardless of its orientation

A picture of a sunglass clock

The first sandglass clock is said to have been made by a french monk named Liutprand during the eighth century A.D. The sandglass clock is also known as the hourglass as it could only tell when an hour was up. They were used to set off blocks of time. And hence, they were all designed to measure one hour. Nowadays if you wish to buy an hourglass/sandglass for decor, there are some that cost thousands of dollars due to their unique history.

Pendulum clocks

This was a big jump in the clockverse when we talk about accuracy. This clock became popular trough the famous scientist Galileo and was the most accurate type of clock till 1930. It was officially first invented by Christian Hyuugans.

A picture of a pendulum to better elaborate Why Do We Use 12 Instead Of 0 On The Clock?
Different types of clocks used in ancient time

A pendulum is the main timekeeping element of a pendulum clock. Clock pendulums are usually made out of weights suspended on a wood rod or a metal rod. In better clocks, the weights are usually heavier as it increases the accuracy of a pendulum. The pendulum is kept in its momentum with the help of an escapement. Each time the pendulum swings through its center position, it releases one tooth of the escape wheel.

The force of the clock’s mainspring or a driving weight hanging from a pulley, transmitted through the clock’s gear train, causes the wheel to turn, and a tooth presses against one of the pallets, giving the pendulum a short push. The clock’s wheels, geared to the escape wheel, move forward a fixed amount with each pendulum swing, advancing the clock’s hands at a steady rate. Usually, the pendulum can also be adjusted, mostly with an adjustment nut. Moving it up causes the pendulum to move faster and so the time is increased while moving it down causes the pendulum to go slower and so the time is decreased.

Why do Clocks run Clockwise?

A video answering why clocks run clockwise

What is daylight saving time and why do some countries change time?

This is quite a unique phenomenon practiced all over the world in many countries. This is done to make the most use of the daylight that is available to us depending on the geography of the place. However, it is important to note that not all of the countries around the world do this. What is it actually? You ask. Well, this basically pertains to all of the clocks within a country to being turned one hour forward in by an exact one hour in spring. And setting the clock back by an exact one hour in autumn. This is basically done to add an hour of daylight in spring and compensate it in autumn when we already have big days

This extra hour of daylight could then be conveniently used by people to go out with their families as they will be getting free from their office and other official duties an hour ahead. And will ultimately have the time to go on and do what they want to do while the sun is still up. This idea was first proposed by George Hudson from New Zealand, who initially proposed a 2-hour time shift in clocks so that he along with his friends would have more time to go for bug hunting in the summer. A few years later, this idea was appreciated by William Willett who then proposed this in front of the Parliament as a suggestion from saving daylight time of the people of the whole wide nation

Two of the many people who supported this idea were Winston Churchill and Sir Arthur Conan Doyle. But this didn’t stop the idea from being rejected in the start by the parliament. And eventually, this idea was first materialised by the German Government.

What is the Most accurate type of Clock?

The answer to this is “Atomic Clocks“. The authenticity of it being the most accurate clock can be inferred by the fact that it looses 1 second after every 138 million years. That’s a big figure. An example of a famous place it is used at is CERN, NASA, and many others.

The clock that the U.S. uses to calibrate its time is accurate to a second in a 100 million years. So if you had put one of these clocks in the medieval ages they will still tell the same time in this day and age.

Data transmission on the internet, as well as the GPS navigational system and cell phone towers and even the high grid, depends on this clock. In conclusion, our high-speed interconnected world works because we can use different pieces of technology using accurate time. So, you take that out of the way, and say good buy to the internet? And isn’t that just sad?

Well, as we have already discussed, atomic clocks have a big impact on our world as a whole. How? is a question that you might be wondering as of now.

Let’s start with the internet, where exact timings are critical. And atomic clocks as we know by now is what helps with that accuracy. Moreover, for GPS satellites to work out your precise position, your timing of the signals it sends and receives has to be super accurate. The signals travel at the speed of light, which means that an error of even a single microsecond error translates to an error of 300 meters on the ground. The timing has to be so precise that even tiny effects like relativity need to be tracked. So we do have Einstein to thank for that because if we didn’t have his equations we wouldn’t have a GPS.

To be exact with each and every microsecond GPS satellites have to carry atomic clocks. The more accurate the clock is, the more accurate GPS can calculate your location

Why don’t clocks appear in dreams?

A picture of a woman draming to answer Why Do We Use 12 Instead Of 0 On The Clock?

We normally don’t see clocks in our dreams but it’s not that rare. It’s just that anything that can give you a frame of time and provide information just seems like gibberish. Moreover, when you dream, time itself loses its purpose, and hence you don’t see many clocks. If you want to read about this in detail, we have an elaborate article on this very topic, so do give it a look if you’re interested “Why don’t clocks appear in dreams? Clocks and dreams!

How does a clock work?

When most of the people ask the question that how does a clock work? they are mostly referring to how does the analog ( quartz ) clock work as that is the most common clock. And the first one that comes to mind when we think of a clock. So here is how an analog ( quartz ) clock work?

Clocks basically use oscillators to keep the gears moving. And the movement of the gears prompts the minute hand to move which then turns and makes the hour hand move.
  1. So basically what happens is that the battery or the power source provides to the microchip circuit within the clock
  2. Then this current makes the quartz crystals that are precisely cut and placed within the clock to vibrate at a speed of 32768 times a second.
  3. TheMicrochip circuit detects the crystal’s vibrations and turns them into regular electric pulses, at a speed of one per second, because as we know that is what is needed for the accuracy and normal functioning of the clock
  4. These electric pulses then turn to mechanical power and move the gears
  5. The one gear that moves makes the other gear move. Hence, making the clock tick every second. Til the appliance of the power remains intact

How do digital clocks work?

Elegant Alarm Clock | Unique Alarm Clock to better answer Why Do We Use 12 Instead Of 0 On The Clock?

Just like the Analog clock, digital clocks also require batteries to run along with an oscillator and more or less works in the same fashion as them. The oscillator in a digital clock is usually in the form of a crystal that is made up of glass. And as the electric charge passes and goes through the crystal, it will cause a lot of vibrations and make a sound. This sound is then converted into an electronic signal. Which, through using a counter is converted to oscillations of 1 Hz oscillations. This is done through the work of various counters. The very first fo which would count 10 oscillations as one. And another one present alongside with it would count 60 as one ( or six 10 ones )

Diving into a bit more depth

This basically becomes the base of hertz being one oscillation for one second. Each counter is connected with an electronic chip that then goes on to signal displays that goes on to signal the display and which then uses light to display the present time of the moment

The display is either an LED or LCD light display which is also referred to as the “7-segment display. The number seven here comes because there are exactly seven segments that can light up for displaying a number. To elaborate on this, the digit “8” uses all of these seven segments to display. These lights are located on the display in such a way so that they can easily display two sets of 2-digit numbers. The electronic innards of a digital clock are derived in a way that they go and change each four of the digits when an hour is up. And keep on going with a sequence and flow

A bit more about how they function

All of these movements seek to achieve perpetual ( smooth motion ). The oscillators that make the gears move are powered by either direct electrical appliances or batteries. Batteries are the most way of supplying power to these time-telling machines. But when clocks were still a bit new, people also used to use a direct connection with electricity to supply clocks with power

Digital clocks mostly use a 50 or 65-hertz oscillation of AC power or in other words a 32,768-hertz crystal oscillator as in a quartz clock to tell time.

Most of the digital clocks out there come with a 24-hour a day format. But some also come with a 12-hour option like in the analog clocks ( in this case, they show an A.M. or P.M. and many come with an option to work both ways. Lets dive into a bit more detail

Digital clocks have highly advanced in their evolution in recent times they are quite commonly used nowadays in forms of alarm clocks and sometimes also for decorative purposes. Now let’s look at some of the most interesting and advanced digital clocks

Hopefully, this article was helpful in answering “Why Do We Use 12 Instead Of 0 On The Clock?” along with some other clock related questions. If you have any other clock related question feel free to use the comment section below and stay tuned to ohmyclock for more interesting articles on clocks

AK Iqbal

A University of London’ student with a passion for writing. Clocks have always intrigued me and the importance that they have in our lives is way beyond phenomenal. So, on this site, I write everything about clocks, everything from answering any clock-related queries that you might have along with recommending some of my favorite clocks accordingly. Moreover, I will also be conducting some researches on clock related topics and sharing the things that I learn. So stay tuned to ohmyclock for all the fun clocks related content

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