# What would be advantage/disadvantage of a different concept of time of day?

I've always entertained the thought that our time system (24 hours, sometimes regarded as 2 periods of 12 hours, 60 minutes and seconds etc.) is an inefficient and unnatural concept.

Besides the computational inconsistency and uncertainty of time declarations, I mostly get frustrated by the fact that none of the units we're using actually corresponds to anything useful.

By that, I mean that a minute is way too fine and an hour way too blunt divider. I've noticed that when I consider my time, it goes in chunks of about 15 minutes. So, a quarter seems a nice choice with additional advantages.

Consider the full day. It consists of 24 hours, which is 96 quarters. If we can approximate it a bit and divide the whole day into 100 parts (or 1000 to be slavishly following the decimal system), we get the quarters to be about 14.4 minutes long, which is roughly speaking what they are today.

The consequence of that would be that half a day is 50 units, a workday is about 30, you wait for a friend for 1 unit before you get PO'ed and the shower takes 2 units, whereas a movie is between 6 and 10 units.

What would be other advantages to such a shift? What would be a disadvantage?

• Are you talking about moving from our current system to this one, or a society that started with this system? Big difference. Commented Sep 4, 2016 at 2:39
• Decimal Time has been tried before. Also, how do you describe less than a "unit" in your proposed system? Commented Sep 4, 2016 at 3:59
• How Long is a Day? Commented Sep 4, 2016 at 6:46
• I actually have no problems with the current time system. This is the first time I have seen someone having problems with it. Why is it inefficient and unnatural?
– Skye
Commented Sep 4, 2016 at 7:25
• @SirTechSpec New one, definitely a new one. Current one has been reluctant to any change since the Summerians. Commented Sep 4, 2016 at 14:51

24 and 60 have great advantage. Dividing. If you need half the time, you can get it. And still have a nice number. One third? No problem. One fourth? Can do. Fifth? Harder, but dozen minutes is just that. Sixth? Tenth? Useful divisions.

With your units, you can't divide them that well. Day is 50 units, so plan three equally time consuming tasks. Not as easy as with 12 hours? Work day is easier to divide, but only because it's 30 - close to traditional system. But try to divide it in four.

Also, tasks like boiling an egg. it takes five minutes. In your world it's 1/3 of an unit. On my stove, it's 7 minutes from cold water to nice soft boiled eggs. Can't tell how long is it in units.

• I see where you come from but I feel that you're missing the beauty of the solution. A day is not 50 but 100 (or 1000) units. Then, a full workday (8 hours) is roughly 300 units. Nothing stops us from using divisibility and say that we work 288 units. As for the egg, it would be 5 units (or half unit). I see how it might work. On the other hand, I do see your point. And people are reluctant to change the customs, hehe. In the long run, though... Commented Sep 4, 2016 at 14:34
• @Konrad a day as in "the time that isn't night". And things like two hours are much simpler than 75 units. Or 7 and a half unit. And 288 units of work? Horrible. People like things to be simple, and in everyday situations your system is anything but. Commented Sep 4, 2016 at 14:58
• @Oh, that's true. Now that you mentioned it, it might be a bit "crude" to normal people. But in the defense, we do work about 168 hours a month and that's not a number bothering anybody... As for the "light part of the day", I welcome you to Sweden. In the larger portion of the country, the "light part" is either 15+ hours or 9- hours most of the year, hehe. Commented Sep 4, 2016 at 15:07

I agree that it would make sense to use a decimal clock. I'd say use the standard metric divisions and prefixes: a day is divided into 10 decidays, or 100 centidays, or 1000 millidays, etc. Computations involving time would be simpler.

I'd quibble that your statement that 1 hour is too long and 1 minute is too short is naïve. It depends what we're trying to measure. Sure, 1 minute is too small a unit to conveniently describe a work day. (Sadly enough.) But it's a very handy unit to measure how long it takes to boil noodles or brush your teeth.

That said, getting people to change would be a huge task. People are used to the present system. They have a "feel" for how long an hour is and how long a minute is. Switching to a new unit would require re-learning. All the clocks would have to be redesigned. (Actually I guess clock manufacturers would love it, as everyone would have to buy new clocks.) Every reference to time in instruction manuals and legal documents would have to be changed. It would be a huge amount of work and expense. I doubt people would do it.

I've often observed that when I was in high school and college and was taking science classes, the metric system was obviously superior, and I couldn't understand why the U.S. did not switch. Then I graduated school and I rarely do calculations with physical units any more. Oh, I care how far away the next highway exit is and how many quarts of oil to put in the back-up generator, but I rarely do CALCULATIONS with units, so which system I use doesn't matter all that much.

And by the way, if you did switch to this system, you'd still have those insane people who say we need to add leap seconds to the calendar to keep it in sync with variations in the rotation of the Earth. As if having the sun rise at 6:28:02 instead of 6:28:01 like it was this day last year is a bigger problem than having essentially random and unpredictable changes to your clock.

• I loved your answer up until the last paragraph. Adjusting times for the rotation of the earth, and indeed quantum fluctuations, are not an inconsequential, avoidable nicety. In fact if it were not for these, your mobile phone, GPS, and many other devices simply wouldn't work. Satellite signals require incredible levels of accuracy to give you the service you are acclimatized to Commented Sep 4, 2016 at 6:30
• Adapting to a new system is definitely the weakest point. It would require a "new order". As for the last paragraph, I don't think that would be an issue. The system I'm thinking of divides the day into 1000 pieces. If those pieces need to be a tenth of a percent longer, one day, then so be it. Nobody would notice, anyway. (It's not applicable to scientific observations, of course, but I'm referring to everyday usefulness and ease.) Commented Sep 4, 2016 at 14:40
• @DarrenH Hmm, I freely admit that I don't know the details of the workings of mobile phones and GPSs. If you know more about it than I do, maybe we could discuss this in chat. I don't see why a mobile phone would depend on the exact time of high noon. Why would that matter? Cell phones don't rely on the position of the Sun for ... anything, as far as I know. GPSs require precise timing to calculate the distance between the receiver and the satellites, but again, what difference does the position of the Sun make to that? "Precise timing" and "synchronization with the Sun" are not the same.
– Jay
Commented Sep 4, 2016 at 23:29
• It won't ever happen because the transition would be a nightmare and the gain at the end of it, small to vanishingly small. There is so much hardware and non-reprogrammable firmware that works in seconds (and minutes and hours). What might happen away from this planet is the adoption of a 100,000 second "day"/ sleep cycle and mega- and giga- seconds for keeping track of longer periods where a "year" has no meaning. Commented Sep 5, 2016 at 12:49

• It is cleaner, if (and that's a pretty bid if) everyone used this, clocks would be cleaner.