When were seconds and minutes invented?
I think hours were invented long ago with those "sun clocks", they made half a circle and cut it to 6 parts, each representing an hour, but no way they also knew about minutes and seconds back then.
'Minutes" and 'seconds' were used by the Babylonians over 2000 years ago. They used a base-60 mathematical system for reasons I don't know (but probably had some ancient astronomical basis, e.g., the earth revolves around the sun in ~360 days, etc.). In any case, numbers like 6, 12, 30, 60, seemed as 'round' to them as 10, 100, 1000 seem to us.
Like many other ancients, they divided the 'day' into 12 parts (which varied in length as the year progressed), and then did the same for the 'night'. So a 'day' was 24 hours long. While for most people, and for many centuries after, the hour (sometimes divided in half, or even quarters) was granular enough, ancient scientists wanted something finer-tuned. So they divided the hour into 60 minutes, and then each minute into 60 seconds. (They did the same thing with geometry: 360 degrees in a circle, each degree divided into 60 minutes, which were divided into 60 seconds.)
Obviously, they didn't have terribly accurate timepieces, so it was probably more of an intellectual exercise for them. As mentioned, accuracy to the quarter-hour was more than enough for most people.
Hundreds of years ago, when what we think of as true 'clocks' were invented, they only used an hour hand. But that doesn't mean they didn't use minutes internally. People could estimate the time to the quarter-hour by just looking at the clock's one hand, which was sufficient for their purposes. No need to complicate the internal workings by adding gears and stuff to drive a minute hand, let alone a second hand. But science demanded ever-increasing accuracy for its measurements, and machinery became more capable, so 'top-of-the-line' timepieces soon got them. No need to invent new terms, or anything, since scientists, at least, had been aware of the Babyonian system all along.

That answer your question?
