Why should one minute be 60 seconds and not 100 seconds?

To understand why 60 seconds.
Let's see where all this began?

Well, to start with, we have to know about the history of the Babylonian period. They derived their number system from the Sumerians who were using it as early as 3500 BC. They decided 24 hours are divided into two parts

• a day lasting 12 hours and a night lasting 12 hours,
• 1hour is 60 minutes and one minute is 60seconds.

But why??

Because they used the duodecimal system(base 12) and sexagesimal(base 60) which led to 12 hrs a day and 12 hrs a night.

Hipparchus gave us the “Equinoctial hours” by proposing the division of a day into 24 equal hours.

'12' is a very special number

The importance of the number 12 is typically attributed either to the fact that it equals the number of lunar cycles in a year or the number of finger joints on each hand (three in each of the four fingers, excluding the thumb), making it possible to count to 12 with the thumb.

The number of finger joints on each hand (excluding the thumb) makes it possible to count to 12 by using the thumb. So it can be said that the structure of our fingers may be the reason!

Another reason behind using '12' is that ‘12’ can be written as ‘6 X 2’, ‘3 X 4’. So that a day can be divided into half and quarters easily. whereas 10 has only three divisors - whole numbers that divide it a whole number of times.

Sixty has 12 divisors and because 60 = 5 x 12 it combines the advantages of both 10 and 12. It is notably convenient for expressing fractions since 60 is the smallest number divisible by the first six counting numbers(1,2,3,4,5,6) as well as by 10, 12, 15, 20, and 30.

Nobody really cared about seconds until after the Middle Ages and all the division of time was mainly to communicate time to others.
If someone asks you what time is it, you can say “half a day completed” or “quarter day completed”.

But imagine what it would be if a day was 10 hrs, it would hard to tell since 10/3 is 3.3333333….. Obviously, it would be difficult to speak. 60 can be divided by 6,5,4, 3, 2. So it would be easy to communicate the time.

Another reason might be with the calculation of degrees.
Longitude is measured by imaginary lines that run around the Earth vertically (up and down) and meet at the North and South Poles. These lines are known as meridians. Each meridian measures one arcdegree of longitude. The distance around the Earth measures 360 degrees. Each degree was divided into 60 parts, each of which was again subdivided into 60 smaller parts.
The first division, partes minutae primae, or first minute, became known simply as the "minute."
The second segmentation, partes minutae secundae, or "second minute," became known as the second.

So now division of time can be connected to the rotation of the earth. Earth rotates 1 degree in 4 minutes. This rotation is a full 360 degree.
So, in one hour, the earth turns 15 degrees. Every four minutes, the earth has turned one degree. So in 60 mins, it would rotate 15 degrees. Now as we have 360 degrees in total to rotate, we take 24 hours to do so. (24×15 = 360).

Isn't this fun to know about this.
Hope you learned something new here and don't forget to comment below your thoughts. Thanks for reading! Keep learning, Keep Growing.