why do the hours of the day start and end in the night?

Question

another question from my son

Answer 1

He's got it the wrong way round, mmm?.

Answer 2

It is arbitrary. As is the number of hours in the day.
For some day ended at sundown, for others the new day began at sunup. For the Romans noon was the cutoff.

Noon makes a lot of sense since sunup and down change throughout the seasons("days" get longer or shorter) but noon (sun at highest point above horizon) is consistantly "one day" from the last time that happened -- at any time of the year.

Now the real answer:
Date changes at the time of day that was guessed to have the least impact on people -- "midnight".

Same logic that puts the international date line in the middle of the Pacific Ocean.

Answer 3

Good question. I guess the answer is to inform your son about the way that the days get shorter and longer during the year. Because of this perpetual cycle it makes sense to pick an arbitrary point which does not change whatever time of year it is. It would be a headache for a day to be eight hours at one time of year and twelve at another.

Answer 4

It is just how we have always had it. You could say that it is 4:27 when in the real world it is somewhere around 9:00. The idea that the day would start and end was adopted from the idea that you start a new day when you wake up, which is usually when its dark outside.

Answer 5

Kids ask the funniest questions don't they?

A day is a span of 24 hours that begins and ends at midnight. That is not to be confused with "daytime" which generally means the time of the day when the sun is visible.

Answer 6

Why is it that we count time 12 a.m. - 11 a.m. and 12 p.m. - 11 p.m..

That counts 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 which isn't in order.


Doesn't it make far more sense to count time from 1 a.m. - 12 a.m. and 1 p.m. - 12 p.m.?

This counts 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 which is in order.


Any logic behind why we don't count time from 1-12?

Answer 7

Purely convention; the Romans reckoned days from midday to midday, since that was a point in time you could actually measure (the moment the Sun crosses the North-South meridian). Professional astronomers continued to use the Roman convention until 1968.

Answer 8

Can you imagine getting to midday and suddenly having to change the date. So at midday tomorrow we will suddenly have to change from 25/10/2007 to 26/10/2007. Surely it is better to make this huge jump when our natural rythyms take a break; ie when we are asleep; which for most of us (apologies to shift workers and insomniacs) is at night. After all when then year number changes a lot of us stay up just to watch it happen. At least I do and I wasn't the only one in the Rose and Crown doing it last year.

Answer 9

Because we are biologically tuned to rest during the dark hours and to be alert and active when it is bright. So, our day factually begins when we get up and ends when we go to bed. The chronological version, day beginning and ending at midnight, is just a more scientific version which allows a common standard time measurement for everyone.

Answer 10

Hello,
What really matters is what time do we give when the sun is at its zenith. That is when it is straight above our head. This is what we called midday (middle of day), 12am. 12 hours later or before, the sun will be on the opposite side of the Earth and it will be midnight (middle of night).
As far as I can presume that is all.

Answer 11

grenwich mean time was based on the sun at 12o'clock midday the earth is 360degrees the sun takes 24hrs to revolve around the earth so every 15degrees east -1 hour and 15 degrees west is+1 hour