Can a clock that measures hours and minutes be created using primitive technology? so at most gears carved out of wood/bone/stone or crude non smitthed copper and when? I tought that maybe a primitive giant clock could be powered a water wheel or maybe even something more primitive.

when would the earliest moment in prehistory people could technically record time with a high precision, like global time... a clock that doesn't care where you build it, in which part of the world you create it and so on...

At first people would count days, weeks and months by hand but if they manage to build the first clock, it can easily be upgraded or more be created that also automatically count the years or decades or millenia passing.

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    $\begingroup$ How high precision do you want? Romans managed without minutes. $\endgroup$
    – Mary
    Commented Aug 28, 2023 at 12:16
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    $\begingroup$ What do you mean by clock? Do you really think of something mechanical (in which case, no, that is not primitive). Or do you mean any time measuring device, like hourglasses or sundials? Both of those could be built with primitive technology, tho the need for precise and synchronized timekeeping in itself already suggests a somewhat developed society $\endgroup$ Commented Aug 28, 2023 at 12:17
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    $\begingroup$ What do you mean by global? Unless they are connected, typical clocks measure elapsed intervals of time independently of each other. A global time system is a convention to establish, not so much a magic device. A "global time measurement" could involve something that establishes simultaneity (a specific thing that people on different parts of earth could measure at the same moment, like a celestial event). Is that what you have in mind? Otherwise, please clarify what a global time-measuring device is to you. You can take a modern example to let us know (without an internet connection) $\endgroup$ Commented Aug 28, 2023 at 12:56
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    $\begingroup$ If your goal is simply to record elapsed time (which is what most clocks do), sundials and water-based variants of hourglasses do that pretty fine and are easy to build (depending on the accuracy). If that is not your goal, you need to specify it more clearly. It is also unclear why a primitive society would need clocks that are globally synchronized up to the minute. If they are primitive, communication from one distant city to another will take days anyway, so that kind of global precision seems futile $\endgroup$ Commented Aug 28, 2023 at 13:04
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    $\begingroup$ In the US, I'm pretty sure we didn't bother with anything like "globally" synchronized time until we had trains traveling hundreds of miles in a day. Before that, you synchronized your clock to something like noon, which depended on you locale. $\endgroup$
    – Jedediah
    Commented Aug 28, 2023 at 14:52

7 Answers 7


My answer would be the second century BC.

The Ptolemaic model of the motion of the planets does not necessarily mean the inventors believed that the planets ran on gears and wheels. Some believe that this was a mechanical way of approximating the weird motions of planets such as Mars, and calculating the future position by successive approximations. If they had a model that had fifty or sixty epicycles, this rather implies that they had a machine that could make gears. We now know from the Antikythera that such a mechanism existed and was used. This is not a clock, but it has most of the technology needed.

Suppose we have a large pendulum. We notice that its swing can be used to mark seconds. If the edge of the swing means the weight meets a stream of falling water, the water will give the pendulum a slight push, keeping it swinging. We can then have another mechanism that the opposite end of the swing that uses the pendulum to push the gear train. This effectively separates the action of an escapement into two separate mechanisms: one that supplies the push, and another that counts the swings. Once we have that, I expect someone smart would have invented the full escapement.

The Chinese had mechanical water clocks from the 6th Century BC. These combined falling water and gears, but had no pendulum. These tried to measure time using the flow of liquid, and the people of the time knew this depended too much on temperature.

So, why did people not have clocks of this form in antiquity? They could measure the motion of celestial bodies. This gave them an accurate idea of days, and the means to subdivide them. They had hour-glasses for timing. But the Egyptians, the Greeks and the Chinese tended to use sundials, and to divide the day from sunup to sundown into equal hours. If they had a need to know exactly how long something took as a fraction of a day, rather than how long to boil an egg, then I think a smart person, given the leisure and the apparatus of the day, could have made a clock.

For the simplest clock, see the timekeeping experiments of Riccioli in the first half of the 17th century. People had clocks with escapements since the 13th century, but he used just a pendulum, with people to count the swings, and to push the pendulum gently if the swing was less than the required angle. He wanted to see whether celestial time matched mechanical pendulum time, so he concentrated on the pendulum. Anyone could have done his experiments well before the 2nd century BC if they had wanted to.

  • $\begingroup$ You can measure time much easier with a pendulum. $\endgroup$ Commented Aug 29, 2023 at 2:27
  • $\begingroup$ My question is why did it take until 1656 to invent the pendulum clock? It seems like such a basic device and doesn't require any fancy manufacturing technology to make it possible. $\endgroup$ Commented Aug 30, 2023 at 14:08

Probably very early, given they have the know how, but you will have to accept some degree of inconsistency between different places.

This is the the most simple design I could come think of:

To measure the seconds, you would need to invent some type of escapement.

An escapement is a mechanical linkage in mechanical watches and clocks that provides impulses to the timekeeping element and periodically releases the gear train to move forward, advancing the clock's hands.

The most primitive type of escapement I can come up with is based on the principle of Shishi-odoshi. As a hobby woodworker, I can say that these are trivial (and fun) to make even with rudimentary tools.

The challenge is to maintain a consistent water flow. However, this could be managed by a system of progressively smaller reservoirs that ensure the last one always maintains the same water level.

Moving from this rather fragile type of escapement to a real clock, I would suggest keeping the entire mechanism lightweight, using materials like rattan to weave the dials instead of using carved gears. The easiest approach would be to have separate but connected dials for seconds, minutes, and hours, standing next to each other. The reading would be done by poles stuck in the ground in front of the dials, while the dials are turning around their axes.

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Each "clack" turns the second dial by one step, representing a "second". The motion is then transferred to the minute dial and the hour dial, and so on if needed.

The contraption itself, as you can see is not that hard to conceive, however there are other challenges:

Since we can't rely on the unique behavior of a pendulum, in order to achieve consistent measurements, you would need to normalize how fast the Shishi-odoshi is filled with water. For this, you need to have a way to communicate the amount of water the last reservoir can hold, the size of the hole through which the water is flowing out, and the dimensions and weight of the Shishi-odoshi between the individual clockmakers. Otherwise, you will end up with different second lengths across the different places.

This presumes the existence of a universal normalization of dimensions and the effective communication of specific instructions across distances, which, in turn, assumes a level of organization in society higher than what we usually imagine in prehistoric times.

Furthermore, time synchronization will be tricky. How will people in different places recognize when "Hour One" begins each day? Some societies may utilize their (usually) megalithic calendar structures to determine the moment when the sun rises on the summer solstice or something similar, but this method will always be prone to errors and not every village can be expected to construct their own Stonehenge to periodically synchronize their clocks.

In our history, we only managed to overcome this problem after developing clocks small enough to transport between places while maintaining consistent operation, and even that solution wasn't ideal.

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    $\begingroup$ Hm, do we have any example of wooden gears used in precision devices? Even with well finished wood, the friction is gonna call for some kind of lubrication, which is not gonna remain constant with time and will lead to discrepancies in the dynamic response of the system. I have doubts that this can realistically measure time accurately. Moving discs increasing in size by a factor 60 is gonna be hard. Forces involved are gonna require a lot more water than the japanese garden things you mention. This thing is gonna turn into a pretty involved engineering project in no time. Doesn't look easy $\endgroup$ Commented Aug 28, 2023 at 14:33
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    $\begingroup$ John Harrison, an 18th century clockmaker, made clocks with wooden wheels. Here is someone who has re-used his techniques. hodinkee.com/articles/wooden-wheels-with-300-years-of-history $\endgroup$ Commented Aug 28, 2023 at 15:22
  • $\begingroup$ According to the article, he solved the lubrication issue that I was mentioning by using a special oily kind of wood that grows in the Carribean and South America. That does suggest that for a primitive european/north american setting, lubrication IS likely gonna get in the way of precise wood-based mechanics. It is in the realm of believable tho, but definitely not a trivial task for people with presumably much lower engineering knowledge and know-how than an 18th century clockmaker. Article also reminds all the challenges that come with getting precision out of a living, changing material. $\endgroup$ Commented Aug 28, 2023 at 16:25
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    $\begingroup$ @BarbaudJulien The gearing here is backwards from what you're thinking. Power is applied from the water at the escapement, and then geared down to the minute/hour wheels. A tiny amount of torque at the first gear ends up as a huge amount of torque (and tiny amount of rotation) by the minute wheel. You wouldn't even need lubrication or precision. Also, Harrison was concerned with precision timekeeping, eliminating lubrication to keep power through the going train consistent where convential clocks apply power at the other end of the gear train. That doesn't apply in this situation. $\endgroup$
    – MrBunsy
    Commented Aug 29, 2023 at 9:37
  • $\begingroup$ @BarbaudJulien Primitive woodworker char wooden surfaces to harden then. A carbon surface would also act as a lubricant. You can get laser-cut wooden clock kits which work with a laser-charred surface. I bet I could make a good working clock from scratch if it was a matter of life or death, but I would probably use my fire-hardened wood for spears or arrows.. $\endgroup$ Commented Aug 30, 2023 at 12:40


Forget about gears and water buckets. Go Solar Greta!!!

Long before your people can cut gears and make escapements, they had the technology to build a Giant Clock that is always accurate and can be as precise as they want it to be. All they need is fairly flat ground with good access to solar observation from sunrise to sunset, some cord and a couple long straight sticks. Four virginal girls for sacrifice to the Sun god optional.

Step 1. Put long stick in the ground and make it straight (can make plumb line).
Step 2. Observe and mark positions of sunrise and sunset on the ground
Step 3. Use geometry and cord to divide the day into as many smaller slices as they want!
Step 4. Sacrifice virgins as necessary.

Since your people are Primitive, and thus Indolent and Uneducated Boobs, they ought to have all the time in the world to tweak their Giant Clock and perhaps build several compensating mechanisms (other clocks) to account for seasonal shift of maximal, minimal and medial day lengths.



Thats when the first clock meeting your requirements was build, and since there was quite the incentive to do so, its unlikely it could habe been done much earlier.

Maybe add a year to that to build a "giant" version, if it needs to be.

To clarify, the limiting requirement here is "global time", that requires synchronizing, and this needs a clock that is still precise when transported. This is a MUCH harder problem than just a clock that measures passed time for yourself.


Here is another possible answer, that has never been used to my knowledge. Use a tide gauge. Have a large chamber that sits in the sea, connected to the sea by a small hole. The height of water in the chamber will be the same as the average height of the sea but it will average out the effects of waves.

This will need constant tweaking as the tides go between spring and neap, but initially you can avoid all the maths if you assume the current tide is much the same as the last one. This is true in most places, though there are places with complex multiple tides. There is also a lack of precision as the tide turns - you get the best precision as the tide is half-way. You may use hour-glasses to span any precision gaps as the tides turn.

Advantages: you can read it in cloudy weather when a sundial does not work. Widely separated tide-clocks should remain in sync. The absolute difference could be calibrated using astronomical observations.

Not quite the same thing, but the Nilometer was used in the times of the Pharaohs.


About 3000-2500 BC

Clocks are simple enough of devices that all of the components needed to make one could theoretically be discovered and applied by a single inventor at any time in history as long as the necessary materials, tools, and math required already exist.


Plain old copper working would suffice. The gears in a clock need to be made to a fair amount of precision; so, primitive ceramics and stone working may not have been good options, but once you hit the copper age (about 5000 BC), you have the materials you need to make a clock copper. On its own, copper is a pretty soft metal, but clocks don't require a very strong material, just one that can be precisely shaped. By 3000 BC, copper working is already a mature science and bronze is already starting to make an appearance.


This is where most people will mess up the required date because they are looking up when we know of tools being invented, but when looking at ancient technology, the first verified example of something is often a gross under-estimation of when it was first invented. Instead of looking for when exact tools were discovered, you need to look for the evidence of tools that are able to do certain things. Ancient Egypt is full of precisely shaped artifacts that require tools that don't appear in the annules history for hundreds or even thousands of years after our oldest examples of the tools needed to make them. This means that things like lathes, drills, saws, etc go back much further than our historical examples of these tools. When you look at the craftmanship of ancient Egypt, there are plenty of examples of objects that are made with symmetry, roundness, and detail down to the 1000th of an inch (~25 micrometers). This is more than precise enough to build the components of a functional clock, especially a large one.


Like tools, the evidence of precise math goes back way farther than the actual textbooks explaining it. To make a clock, you need to understand some concept of either division or ratios and angles or symmetry. Again, going back to ancient history, there is a lot of evidence of math that is able to do these things that spread around 3000BC based on changes seen in economics, architecture, and craftsmanship even though the first written record of math is not found until about 2000BC.

So, it is very possible, that a craftsman born in Ancient Egypt would have been taught how to work with copper or bronze, caste or grind that copper into a nearly perfect circle, divide a circle into nearly prefect increments, and be able to work in fractions. With this skill set, one could easily figure out in a single lifetime how to make a clock, if he were tasked or motivated to do so. The late entry of mechanical clocks into the historical record likely has more to do with a lack of necessity than lack of ability. Until the development of modern industry, there was just no need to break time down more precisely than a much more simple sundial could do.


Ancient Mesopotamia. 3000-4000BC, wood/pottery clock is possible. 5000-6000 Years ago.

But concept of precise clock was not a point till precise navigation and raiload synchronisation was needed. Eariler a day was enough.

Main point is to have time and craftspeople to do it. That means basic agriculture and basic goverment. But at first - need a reason to spend a lot of resources to do it (food, slaves, army, trees...)

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    $\begingroup$ Do you have any source for the claims? I'd be very curious to see what you mean by a "clock" in ancient Mesopotamia (clock is defined as a mechanical or electrical device in my dictionary) $\endgroup$ Commented Aug 28, 2023 at 12:18
  • $\begingroup$ The isochronism of the oscillations of a pendulum was discovered by G. Galilei in 1602; that's the minimum knowledge required for making a sort-of accurate mechanical clock. And no, "a day" was not enough. For example, the Romans routinely specified time to the hour. And, of course, astronomers measured time to minutes and seconds ever since the Babylonians... $\endgroup$
    – AlexP
    Commented Aug 28, 2023 at 12:32
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    $\begingroup$ In the case of Mesopotamia and ancient Egypt, the clocks were mostly outflow type water clock, but clepsydra may have been also used. Definitely the sundial ("sun clock" in many languages) was used as well. Each of these can be used to measure time span shorter than a minute. As far as terminology goes "Clock" does not have to be mechanical or electrical. $\endgroup$ Commented Aug 28, 2023 at 12:40
  • $\begingroup$ @byMaelstromer ok, I'm not so sure what the official terminology is. I checked in the Oxford dictionary (English is not my first language), which specified electrical or mechanical $\endgroup$ Commented Aug 28, 2023 at 12:51
  • $\begingroup$ @byMaelstromer: The question is obviously about some sort of mechanical timepiece. I hope that the OP knows that the sun and the stars have been used as timekeepers since pre-historic times with no need for gears or a power source. $\endgroup$
    – AlexP
    Commented Aug 28, 2023 at 13:02

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