5 ms·
The way to remember this that finally clicked for me is that 'A' means 'ante', 'P' means 'post', and 'M' means Meridian some Latin word that means the sun is di
by mauvehaus 5y ago
The way to remember this that finally clicked for me is that 'A' means 'ante', 'P' means 'post', and 'M' means Meridian some Latin word that means the sun is directly overhead. Or more practically speaking: noon.
12:00 PM is noon because one minute later, the sun is past being directly above. That is, it's 12:01 Post Meridiem. Since it would obviously be nonsensical for 12:00 AM to be immediately followed by 12:01 PM, noon is 12:00 PM by convention.
Extending this logic to midnight is left as an exercise to the reader.
Don't feel bad, I don't think anybody explained this to me until I was almost 30.
- martin_a 5y agoDoes not make any sense at all. You jump from "sun is overhead in 12 hours" (12 AM) to "sun is overhead in 1 hour" (1 AM) when you follow that logic. The 12 hour-system is broken and should go away.
- Koshkin 5y agoWould you want the clock face to be changed to show 24 hours instead of 12? (What would be the number at the top then - 0 or 24?)
- hnbad 5y agoEasy alternative: start the clock at zero like a rational individual would. 12 only makes sense if you see it as the end and go backwards from there. It's a bit like the confusing mess of how year numbers work where traditionally there is no year zero (because the year one is 1 AD, i.e. the first year "of our Lord", i.e. year numbers are actually ordinal even though everyone treats them as nominal). Besides, at this point 90% of the time formats people look at in their daily lives are probably digital (since analog faces are only relevant to actual clocks and even most clocks are likely digital simply because so many electronic devices come with digital clocks) and even analog clocks don't always have numbers on them (or use fanciful alternatives like Roman numerals). The people who prefer analog clocks are clearly just sticking with them out of personal preference or aesthetics anyway.
- majewsky 5y agoYou're making it sound as though a 24-hour format is a wild new idea when it's actually in common use across 100+ countries. Timestamps go from 00:00:00 to 23:59:59 without breaks in continuity. The clock still has 12 hours with the 12 on top, but it is commonly understood that "12" on the clock face can refer to either 0 or 12, just like how "5" can refer to either 5 or 17.
- softwarebeware 5y agoWhat’s the difference? In both the 12 and 24 hour system the clock rolls over at the end of the period, and the period starts.
- seba_dos1 5y agoThe difference is that in 12-hour system, the rollover point is ambiguous and non-intuitive (11 PM -> 12 AM -> 1 AM), while in 24-hour one it's perfectly clear and obvious.
- Koshkin 5y agoI find the 12-hour system as intuitive as the 24-hour system. It is centered around noon, where "AM" means time on the same day before noon, and "PM" means time after, on the same day. Nothing wrong with that.
- seba_dos1 5y agoThat's only because you're used to it and have additional context already. The day starts at 12 and goes to 1 an hour later, so notion of "same day" is absolutely ambiguous.
- softwarebeware 5y agoThe 24 hour system: 23 -> 0 -> 1 How is that different than 11 -> 12 > 1 ? Yes I get it that in normal integers, 1 is not after 12, but neither is 0 after 23.
- mauvehaus 5y agoUh, doesn't 1:00 AM mean the sun is overhead in 11 hours?