Why is time not decimal?
Have you ever wondered why there are 60 seconds in a minute and 60 minutes in an hour? Why not 100? Why do we use the decimal system for counting, but time is measured in a sexagesimal system? Wouldn’t it be more convenient to have a consistent decimal system for everything? To measure both distance and time in the same system? Or not?
Why are there 60 seconds in a minute?
Good question. But it’s not where you should start. It’s better to first understand why there are 24 hours in a day and why there are 12 numbers on a clock. Then, you can see why there are 60 minutes in an hour, and so on. For that, we need to dive into history. Very far into the past.
On these clocks, there is only one hand, and that’s all you need
Ancient Sumerians used a base-12 counting system. It was very convenient for trade calculations. After all, it’s easy to count “on your fingers”. All you need is to touch your thumb to the phalanges of the other fingers. Look at the picture. This history is explained here.
Why are there 60 minutes in an hour?
Since the ancient Sumerians were essentially the first civilization on the planet, their “convenient” mathematics and, importantly, astronomy were passed on to Babylon and then to all other peoples. If you multiply 12 by 5, you get 60. The base-12 and base-60 systems are actually related.
Since the ancient Egyptians adopted astronomy from the Babylonians, and the Greeks learned it from the Egyptians, we now have a day divided into two periods of 12 hours each.
Why 12 hours makes sense is clear now. But an hour didn’t always have 60 minutes. In fact, there were no minutes at all.
The Romans were the first to divide an hour into minutes. The phrase pars minuta prima translates as “the first small part,” and pars minuta secunda means “the second small part.” So, the hour divided into 60 for the first time means 1 minute, and 1/60th of an hour divided by 60 again is 1 second.
However, for a long time, clockmakers couldn’t create anything more complex than a clock with one hand. And they didn’t really try, as such accuracy was sufficient. To understand this, it’s clear that “quarter past four” doesn’t require a minute hand.
Now it’s clear why there are 60 minutes in an hour and 60 seconds in a minute, instead of 100. It happened historically because it was more convenient to divide an hour into fractions.
Keep reading to find out that attempts to abandon 60 were made, but it turned out to be too inconvenient. Nevertheless, humanity found this system convenient for a long time…
How many seconds are actually in a minute?
For a long time, it was believed that there were 86,400 seconds in a day. 24*60*60 = 86400. You just need to take the period of the Earth’s rotation and divide it into 24, then two times 60. But the modern second is something different.
The atomic second is 9,192,631,770 radiations of a cesium-133 atom, which is at rest at 0 Kelvin temperature.
Interesting fact — not every minute has 60 seconds!
Every year, on June 30 or December 31, a “leap second” is added, making it 61 seconds in one minute. This is done to keep Coordinated Universal Time (UTC, based on atomic clocks) synchronized with Universal Time (UT, local mean solar time at the prime meridian).
Why 24 hours?
It’s not only digital clocks that show time in a 24-hour format. There are also “round” 24-hour clock faces. Who might need that?
In ancient times, the 12-hour format was enough for daylight hours, with 12 hours for nighttime. After all, everyone understood where the day ends and the night begins. That’s why the position of the hands at 12 is called “noon” or “midnight.” Why complicate things?
But in professions that require maximum accuracy, the 24-hour format became standard. For example, for the military to plan operations (to avoid ambiguity in documents), for medical personnel, and finally, for sailors, especially submariners (who are in total darkness).
24-hour clock
In the USA, this time format is called “military time.” Civilians use the 11:30 p.m. format (post meridiem — after noon), while the military uses “23:30.”
Decimal Time
We’ve cleared up the 60 minutes, now the question remains: why are there not 100 seconds in a minute? After all, that would be simpler. Why hasn’t anyone made clocks using the familiar decimal system? In fact, there have been attempts.
Decimal clocks. The dial is divided into 10 hours.
These are “decimal clocks” where the dial has only 10 hours. But in reality, it refers to dividing the entire day into 10, rather than splitting it in half and then dividing by 10. That’s why the dial is duplicated with a second one divided into 24 hours.
- 1 decimal hour = one-tenth of a day = 2.4 hours in our usual format.
- 1 minute = 1/100 of a day = 1.44 minutes
- 1 second = 1/10,000 of a day = 0.864 seconds
Attempts to introduce such clocks were made during the French Revolution, along with the metric system… But as you can see, it didn’t work. This time format lasted only 13 years. What do you think, why?
What’s wrong with decimal time?
First of all, it’s very difficult to divide the day into equal parts without remainders. For example, a decimal day (10 hours) can be divided into 2, 5, and 10, but it’s hard to divide it by 3 without a remainder. But when we have 24 hours in a day and it’s divided into 12, there are many more divisors: 2, 3, 4, 6, 12.
It’s much easier to divide (measure) time into equal intervals. The day can be easily divided in half, into thirds, quarters, and even sixths. Try doing the same with ten.
Also, it’s easy to divide a circle into equal parts using a compass (which for a long time was the only tool). And dividing it by 3 is the easiest.
There are two facts that explain why there are 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute, instead of 100 or 50.
- It happened historically… Thanks to the Sumerians and their “12 fingers.”
- It’s convenient. It’s easy to divide by 2, 3, and 4. And that’s the simplest explanation.
That’s why the ancient timekeeping system has survived all these centuries. It’s simple and convenient. There are 60 seconds in a minute and 60 minutes in an hour, not 100, because it’s convenient. And that’s the main thing, for lazy creatures like us, humans.
In some cases, it’s convenient to use the decimal system, in others, the sexagesimal system, and sometimes the binary system works best.
