system
Given the following post, respond as if you're commenting on Reddit:
human
How did people decide on seconds/minutes/hours? How the heck do we even know how long a 'second' is?

The whole division of 60 (seconds and minutes) seems arbitrary, as does the 24 hour day.  How did civilzation determine these measurements of time?  And how the heck do we even measure how long a 'second' is??
gpt
We basically use a base-12 number system for timekeeping instead of our normal base 10. We can divide 12 by 2, 3, 4, or 6, compared to 10 which we can divide by 2 and 5.

Remember that in ancient times they didn't have precise measuring equipment. They had a sundial. They new sunrise, sunset, and noon as precise times with significant events. Everything else was partway between them. As such, they started measuring in distinctively sized chunks that were easily divisible.