Why are clocks 12h, not 24h?

Piwoslaw · 12-23-12, 02:24 PM

I got thinking about this today. Ever seen a clock face with 24 hours, instead of 12? I've seen one, but they are very hard to come by. Why? Why is it that we divide the day into 24 hours, yet we build our clocks to show only 12? Why does the hour hand have to go around twice each day? I know of many situations when this has lead to confusion, so why have we held on to the 12 hour clock face for so long?

At first I thought it has to do with tradition, nature, etc. but the sun goes by overhead only once per day, so a sundial's "hand" wouldn't go around twice.

roflwaffle · 12-23-12, 07:30 PM

It could be resolution.

Xringer · 12-24-12, 09:43 AM

I've seen some 24 hour clocks while I was in the service.. Didn't like them.

The resolution was okay.. Because of the 0-60 numbers were there too.

I think the original designer used 12 hour movements/face, to save money.

I love my solar watch for it's nice numbers.. But my wife has a smaller version without any numbers!

I remember my first day in Boot Camp.. After lunch, add 12 and stop after midrats.

Exalta-STA · 12-24-12, 10:49 PM

Yeah that also bothers me, got the kids some inexpensive digital watches but couldn't find an inexpensive formal looking watch for work.

Blue Bomber Man · 01-31-13, 10:50 PM

The reason is because 12 is a divisor of 60, 24 is not

Blue Bomber Man · 01-31-13, 10:54 PM

Additionally a minute and an hour were both chosen to be 60 for the reasons regarding math. 60 is divisible by 2, 3, 4, 5, 6, 12, 20, and 30. This made math with time quite easy back in the day without calculators.

MN Renovator · 02-01-13, 06:46 AM

It is very difficult to use a 24 hour clock from a distance, even when you get familiar with it because the hours are closer and it feels like I'm trying to read the electric meter rotary numbers from 6 feet away quickly when I want to just glance at the time. With the 12 hour clock I can see a clock across a room and know where the hour hand is pointing without trying to determine its position between one hour or the next. Is it 1530 or 1630? I can't tell.

I think I'd need a bigger clock or be closer for it to work nicely. I'd prefer to avoid the higher resolution of the hour hand, especially if my better than 20/20 sight ever fades on me. FWIW, I use a watch but have 24 hour international clocks at work. If I want to see Greenwich time or some other time zone I need to use them, especially when it comes to time stamping and sometimes it can be a pain.

Exalta-STA · 02-05-13, 02:20 AM

One thing that makes me quite attached to digital gadgets is when a client tells me to call them up at 8 in the morning..I'm like so is that gonna be Eastern, Central, PST or what?

12-23-12, 02:24 PM	#1
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	Why are clocks 12h, not 24h? I got thinking about this today. Ever seen a clock face with 24 hours, instead of 12? I've seen one, but they are very hard to come by. Why? Why is it that we divide the day into 24 hours, yet we build our clocks to show only 12? Why does the hour hand have to go around twice each day? I know of many situations when this has lead to confusion, so why have we held on to the 12 hour clock face for so long? At first I thought it has to do with tradition, nature, etc. but the sun goes by overhead only once per day, so a sundial's "hand" wouldn't go around twice. __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

12-24-12, 09:43 AM	#3
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I've seen some 24 hour clocks while I was in the service.. Didn't like them. The resolution was okay.. Because of the 0-60 numbers were there too. I think the original designer used 12 hour movements/face, to save money. I love my solar watch for it's nice numbers.. But my wife has a smaller version without any numbers! I remember my first day in Boot Camp.. After lunch, add 12 and stop after midrats. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

12-23-12, 07:30 PM	#2
roflwaffle Apprentice EcoRenovator Join Date: Sep 2008 Posts: 116 Thanks: 29 Thanked 12 Times in 11 Posts	It could be resolution.

12-24-12, 10:49 PM	#4
Exalta-STA Apprentice EcoRenovator Join Date: May 2012 Location: Philippines Posts: 107 Thanks: 12 Thanked 4 Times in 4 Posts	Yeah that also bothers me, got the kids some inexpensive digital watches but couldn't find an inexpensive formal looking watch for work.

01-31-13, 10:50 PM	#5
Blue Bomber Man Lurking Renovator Join Date: Jun 2009 Posts: 24 Thanks: 3 Thanked 5 Times in 5 Posts	The reason is because 12 is a divisor of 60, 24 is not

01-31-13, 10:54 PM	#6
Blue Bomber Man Lurking Renovator Join Date: Jun 2009 Posts: 24 Thanks: 3 Thanked 5 Times in 5 Posts	Additionally a minute and an hour were both chosen to be 60 for the reasons regarding math. 60 is divisible by 2, 3, 4, 5, 6, 12, 20, and 30. This made math with time quite easy back in the day without calculators.

02-01-13, 06:46 AM	#7
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	It is very difficult to use a 24 hour clock from a distance, even when you get familiar with it because the hours are closer and it feels like I'm trying to read the electric meter rotary numbers from 6 feet away quickly when I want to just glance at the time. With the 12 hour clock I can see a clock across a room and know where the hour hand is pointing without trying to determine its position between one hour or the next. Is it 1530 or 1630? I can't tell. I think I'd need a bigger clock or be closer for it to work nicely. I'd prefer to avoid the higher resolution of the hour hand, especially if my better than 20/20 sight ever fades on me. FWIW, I use a watch but have 24 hour international clocks at work. If I want to see Greenwich time or some other time zone I need to use them, especially when it comes to time stamping and sometimes it can be a pain.

02-05-13, 02:20 AM	#8
Exalta-STA Apprentice EcoRenovator Join Date: May 2012 Location: Philippines Posts: 107 Thanks: 12 Thanked 4 Times in 4 Posts	One thing that makes me quite attached to digital gadgets is when a client tells me to call them up at 8 in the morning..I'm like so is that gonna be Eastern, Central, PST or what?