What is rm on the clock. Time in PDT and EST

Everyone who is interested in learning English has had to deal with strange notation p. m. and a. m, and in general, wherever time is mentioned, for some reason only 12 hour format. Probably, for us living on a 24-hour pattern, this is really strange, but if you understand this phenomenon, everything will fall into place.

So, let's start with the fact that in Western countries it is accepted 12 hour time system. The idea is that the 24 hours that make up a day are divided into two intervals of 12 hours, which are denoted as a. m.(lat. Ante meridiem - “before noon”) and p. m.(lat. Post meridiem - “afternoon”). This format is predominant in the USA, Canada, Australia, France, Turkey and some other countries.

This tradition has ancient roots, as the 12-hour time format was used in Mesopotamia and Ancient Egypt. The Egyptians used a sundial for use during the day, and at night they used a water clock or clepsydra (translated from Greek - “water thief”). The Romans also used the 12-hour time format.

You need to remember that the time from 12 noon to 12 night denoted by two letters p. m. (read - pi em).

For example:

3:30 p.m. m. – Fourth half (of the day)

6:15 p.m. m. – Fifteen past seven (pm)

8:40 p.m. m. – Twenty to nine (pm)

Time from 12 noon to 12 noon denoted by two letters a. m.

For example:

1.00 a. m.– Hour of the morning

7:45 a.m. m. – Fifteen minutes to eight (morning)

But, native speakers for convenience in spoken English instead of a. m. and p. m, after the numbers indicating the time, add:

in the morning(morning) - (from 01.00 to 11.59)

in the afternoon(in the afternoon after noon) - (from 12.00 to 16.59)

in the evening(approximately from 17:00 to 21:59)

at night(in the evening after 22:00 and before 00:59).

But as I said, if official English is used, then it is usually used a. m. and p. m.

For example:

19:45 – fifteen till eight in the morning

2:00 – two o'clock in the morning

(Remember, if you want to say the time in hours without specifying minutes, then we say the number of hours and add - o'clock, as in the example above).

14:05 – two zero five in the afternoon

21:30 – nine thirty at night

And now the basic rules:

To say that now is so much time, you need to start with the words: It is
	It is three o'clock a.m. - it's three o'clock in the morning.
If we want to say that at some time we are doing something, we use the preposition at :
	I will phone you at five minutes past 10 – I'll call you at five past nine
Use the preposition - pastwhen talking about minutes from the first to half an hour. (minute hand from 01 to 30) and say how many minutes have passed since the full hour:
	It is fifteen minutes past two fifteen minutes past two(literally: fifteen minutes after two). Often the word minutes in the sentence is omitted - It is fifteen past two
Use the preposition - to when talking about time after half an hour (from 31 to 59 minutes): It is six minutes to five - Without six minutes of a quarter (literally - six minutes to five)
	It is fifteen minutes to eight Quater to eight(literally - fifteen minutes to eight)
To denote "a quarter of an hour", i.e. 15 minutes the word quarter is used. This concept can be used both before and after half an hour, and it is always used with the indefinite article “a”:
	It is a quarter past three Fifteen minutes past three
Half an hour is denoted by the word - half. This word is used without an article:
	It is half past two Half past two

The change of day and night naturally divides the day into two parts. And this significant difference between the time of day was reflected even in the language. We say "at two o'clock in the afternoon" or "at two o'clock in the morning" to emphasize whether the action took place during the day or at night. And there are two more wonderful words in Russian for this purpose: “afternoon” and “midnight”.

In ancient times, time was determined differently day and night. During the day, if the sun was shining, then according to the sundial. And at night - by sand or water clocks, measuring the amount of expired sand or water. Who needed to measure time at night? Guards and stargazers. The shepherds did without watches, determining the time by the stars. Later, when navigation appeared, knowing the exact time became a guarantee that the ship would not get lost at sea, losing sight of the coast. Therefore, on the ship, one of the important watch posts was at the hourglass. The sailor watched the stream of sand and turned the hourglass over when the sand finally poured from the top of the bottle to the bottom. What he immediately signaled, for example, by striking a bell. Usually the “factory” of the hourglass was enough for a quarter of an hour, so the bell on the ship rang every fifteen minutes. This was called "beating the flasks."

As you can see, there was "day" time and "night" time. When, already in the Middle Ages, tower clocks appeared in cities, their dial was divided into 12 sectors, because they were actually “daytime”, at night, in the darkness, the dial could not be seen. And if on the tower clock the arrow pointed to the number "7", people themselves were unmistakably oriented, either it was time to open a shop, or the working day had already ended. Pretty soon, chimes were invented, watches in which time could not only be seen on the dial, but also heard by the corresponding number of bell strikes.

For many cities, the clock has become one of the attractions. The clock mechanism was forced not only to ring the bells, but also to show whole puppet shows. If the clock was high on the tower, then the dolls were made huge so that you could see them from below. Sometimes, on the contrary, the clock was lowered lower. Every hour people gathered to them to stare at the moralizing mechanical mystery. Probably the most famous clock of this type is the clock on the Town Hall Square in Prague.

The dial of this watch, by the way, is divided into 24 sectors. They show not only "day" time, but also "night" time too. Also day and month.

The two systems of calculating the time of day that had developed in this way seemed to cohabit on the same territory. In oral speech, the twelve-hour system was preferred, with the addition, if necessary, of indicating the time of day. Moreover, the watches that appeared in personal use, pocket and wrist, usually had a dial divided into 12 sectors. In writing, that is, mainly in orders and directives, the twenty-four hour system was preferred. This made it possible to avoid ambiguity, which was especially important in military affairs. Bringing a regiment to the river and crossing to the other side at four o'clock in the afternoon or at four o'clock in the morning are completely different things, aren't they? In the United States and Canada, the twenty-four-hour system for representing the time of day is called “military” or “astronomical”.

In everyday life in these countries, the twelve-hour system is practically the standard. In this system, the hour of the day is indicated by a number from 1 to 12 with the addition of two letters, AM or PM. These letters are an abbreviation of the Latin words "ante meridiem" ("before noon") and "post meridiem" ("afternoon").

Usually, the question arises as to how noon and midnight are designated in the twelve-hour system. The convention is that 12:00AM is noon and 12:00PM is midnight. Therefore, the minutes of the first hour after noon in the twelve-hour record are designated as follows: 12:15AM. This corresponds to 12:15 in the twenty-four hour record. The time of the first hour after midnight is 12:30PM. This corresponds to 0:30 in a twenty-four hour recording. That is, there is no zero in the twelve-hour time system. Its role is played by the number 12.

Today, once and for all, we will find out what am and pm mean in English, how these abbreviations are deciphered and how to correctly call time from them.

What is the difference between am and pm?

AM and PM are abbreviations used to indicate the time of day. Both of them came to English from Latin.

AM (ante meridiem) - before noon [hey um]
PM (post meridiem) - after noon [pi em]

They can be found in countries where the twelve-hour time format is adopted. These include Canada, the United States, New Zealand and the Philippines. Together with the generally accepted 24-hour format, 12-hour is also used in the UK, Brazil and a number of other countries. They can indicate the time in any way. In other countries, the twenty-four-hour time format is adopted, which is familiar to us.

The 12-hour format divides the day (24 hours) into two segments of twelve hours.

We use a.m. when talking about the interval from 12 noon (midnight) to 12 noon (noon). That is, from 00:00 to 12:00.

For example:
It's two a.m. - Two in the morning (2:00).
It's five a.m. - Five in the morning (5:00).
It's ten a.m. - Ten in the morning (10:00).
He comes at 9 a.m. - He comes at 9 am.
The train leaves at 11 a.m. - The train leaves at 11 am.

p.m. We use it when we talk about the interval from 12 noon (noon) to 12 midnight (midnight). That is, from 12:00 to 00:00.

For example:
It "s two p.m. - Two in the afternoon (14:00).
It's five p.m. - Five pm (17:00).
It's ten p.m. - Ten in the evening (22:00).
We met at 11 p.m. - We met at 11 pm.
The train leaves at 11 p.m. - The train leaves at 11 pm.

Noon and midnight

Despite the international standards for designating the 12-hour format, there is still no unambiguity between the designation of such insidious time as “noon” and “midnight”.

Some indicate noon as "12 a.m." ("12 ante meridiem", or "12 o'clock until midday"). By this logic, midnight can also be referred to as "12 p.m." (12 post meridiem or 12 hours after the previous midday).

The Greenwich National Maritime Museum suggests that midnight be referred to as "12 noon" and noon as "12 noon". And many American certified style guides suggest designating midnight as 11.59 p.m. to emphasize the end of one day, but already designate the beginning of the next day as 12.01 a.m..

By the way, it is precisely because of the difficulties in understanding and determining time using the 12-hour format that the US Army has been using the 24-hour format since World War II, which avoids errors in navigation and marking the time of hostilities.

If in doubt about how to correctly indicate this time of day, discard the numbers and say in full:

Midday - noon
Midnight - midnight

For more information on how to talk about the time of day in English, see this article:

Comparison table of 24-hour and 12-hour time formats

How to write and use am and pm correctly?

There are several ways to write the 12-hour time format:

> Dotted: a.m. and p.m.
> No dots: am and pm
> In words: AM and PM

The most correct of the three is spelling with dots, but you can often find the other two. In any case, these designations are placed after the numbers, like the well-known o'clock.

Very often, the abbreviations am and pm are found on electronic clocks, in the working hours of the enterprise, and also in the schedule of transport or classes.

For example, if you see "The office is open from 9 a.m. to 6 p.m.", it will mean that the office hours are from 9 am to 6 pm.

Also, be careful when scheduling a meeting and make sure that your interlocutor understands the agreed time correctly.

Example sentences with am and pm with translation

It is five fifteen AM- It's five fifteen in the morning.

It's eight thirty PM- It's eight thirty in the evening.

We must send this letter at 2 a.m.- We have to send this letter at two o'clock in the morning.

Tomorrow I'll wake up at 6 am, not later- Tomorrow I will wake up at six in the morning, not later.

Today I'm going to work up to 8 p.m.- Today I'm going to work until 8 pm.

It is not polite to call somebody concerning a job offer before or after working hours, or during weekends. Also it is better to make personal calls from 9 a.m. till 10 p.m.- It is impolite to call someone about work before or after work hours or during weekends. Also, it is better to make personal calls from 9 am to 10 pm.

Pharmacies in Prague are usually open Monday to Friday from 9 a.m. to 5.30 p.m. and on Saturday from 9 a.m. till noon- Pharmacies in Prague are usually open Monday to Friday from 9 am to 5:30 pm and on Saturdays from 9 am to noon.

The hotel offers 10 guest rooms, a secured car parking and a restaurant with working hours from 9 a.m. till 11 p.m.- The hotel offers 10 guest rooms, secure parking and a restaurant open from 9 am to 11 pm.

From 7 a.m. till 11 a.m. buffet breakfast is served for the guests of the hotel's restaurant on the first floor- From 7 am to 11 am, breakfast is served at the hotel's restaurant on the ground floor.

Children under 16 may not be hired for work from 8 p.m. till 6 a.m. Teenagers under 18 may not be hired for work from 10 p.m. till 6 a.m., or from 11 p.m. till 7 a.m.- Children under the age of 16 cannot be employed from 8pm to 6am. Teenagers under the age of 18 cannot be hired from 10pm to 6am or from 11pm to 7am.

We are accustomed to measuring time in days in hours. But the day was not always divided into 24 hours, and in the modern world, not everyone uses such a system. In China, time was measured in "ke" or "shi". The number of ke per day was 100 units, and shi was 12, these are double hours.

10 hours a day

During the era of the French Revolution, the day was divided into 10 hours, each with 100 minutes. And, for example, astronomical time is calculated in fractions of a day. In ancient Rome, time was determined in guards, four guards of three hours each.

The official division of the day into 24 hours

The official division of the day into 24 hours was introduced in ancient Greece by Claudius Ptolemy in the 2nd century AD. The ancient Egyptians, even 2 thousand years before our era, divided the day into: 12 night hours, 10 daytime hours and 1 hour each for morning and evening twilight. But then they reformed such a system, dividing the day into 12 daytime hours and 12 nighttime hours.

Despite the widespread belief that the current system of calculus came to us from Ancient Babylon, it is erroneous and is based on the "History" of Herodotus.

double hour

In fact, in Babylon they used a double hour, consisting of 120 minutes, but the concept of an hour did not exist then. The division of the day into 24 hours is the merit of the ancient Greeks.

What formats are currently in use

In the modern world, two systems of calculating the day, French and English, have been preserved. French has a 24 hour format, while English has 12 hours. The division into intervals before and after noon for 12 hours, is widely used in many countries for informal communication, along with French.

Daytime hours before noon are designated am, and after 12 as pm. It comes from the Latin ante meaning before, and post meaning after.

This format is used in Canada, USA, New Zealand, Philippines and Australia. And in the UK, Brazil, France and some other countries, both are used.

Understanding it is not difficult, but it is necessary for communication.

It has only two periods before noon and after, the Latin letter p in the designation pm, for ease of remembering, can be perceived as “pe” Russian. Then it will be easier to remember p - after.

Many people use other associations with the letter p to remember, for example, later or later.

Associations

But to define pm as after noon, the best and correct word to remember is after. Time 12 in such a system is designated without any abbreviations, this is the starting point.

The fact is that in Latin meridiem means noon, this is not an exact definition, but rather a literal one. Therefore, to indicate the end of the day, sometimes they write not 12, but 11:59 p. m., and the beginning of a new day looks like - 12:01 a. m.

English system in Russia

Many problems for the Russians are created by electronic clocks with the English time format. Everything is clear in the clock with arrows, but on the electronic clock 14:30 there will be no inscription, the clock shows intervals up to 12.

The time 14:30 in our opinion, on a clock in a different format will look like 02:30 pm, and the beginning of a new day starts from 00:00:01 am and ends at 11:59:59 am. The term noon is used to define noon, and 12 o'clock at night is midnight.