my nephew's clock

What is the meaning of this question?

It is not the same time?

Of course it is the same time.  Here comes the problem of how we “name” the time.

One day has 24 hours, isn’t it? then let’s name them.  Therefore after 12 noon comes 13 and 14 and 15… and we will end the day -midnight- at 24 (or 00.00 – both are used without distinction).  This is called the “24-hour clock” and is a convention of time keeping in which the day runs from midnight to midnight and is divided into 24 hours,  indicated by the hours passed since midnight, from 0 to 23. This system is the most commonly used time notation in the world today.

But usually we don’t say “I saw James at 14.15…” , most of us will robably say “I saw James at 2.15 in the afternoon”.  Therefore it makes sense to say that the 12-hour time is mostly used in speech for ease of use, and 24 hour time is preferred in writing.

The 24 hour clock has also been called railway time (in Europe, therefore in Barcelona), continental time (in England), and military time (in the US).   It is also the international standard notation of time.  In the 12 hour time system, midnight is usually written as 12 AM, and midday (noon) as 12 PM.  The Latin tags Ante Meridiem (before the middle of the day) and Post Meridiem (after), abbreviated to AM and PM, are required to indicate the difference between, say, 1:30 in the morning (01:30) and 1:30 in the afternoon (13:30). You forget about AM and PM if you use the 24 hour time system.

A quick tip to convert easily the 24 hour time nomenclature into the 12 hour use from 12 (noon) onwards -needless to say only for the PM hours-  is to subtract 2 from the hour, and the last (hour) digit will tell you what the time is.  That way:

The 24 hour tower clock in Venice that lists hours 1 to 12 twice

13.00 hours – 2 = 11.00 hours (the last digit is 1 therefore it is 1 PM)

17.30 hours – 2 = 15.30 hours (the last digit is 5 therefore it is 5.30 PM)

22.55 hours – 2 = 20.55 hours (the last digit is 0 therefore it is 10.55 PM)

23.00 hours – 2 = 21.00 hours (the last digit is 1 therefore it is 11.00 PM)

and of course 24.oo (or 00.oo) is midnight because 24 – 2 = 22 and this means a 12 !!  NOTE that minutes remain the same…

Enjoy your time!