Clocks 213

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clocks

Analog and Digital Clocks Animation

You can change the time by moving the hands of the analog clock or by using the buttons on the digital clock (just like on a wristwatch!).

ClocksIn our world we have digital clocks (they have digits like 0,1,2,3) ...

 ... and analog clocks (they have hands) ...

Very important.

What do they have the clocks?

Clocks have hands one tall and one short. The long hand is called the minute hand, the shorter one is called the hour hand.

This is called the minute hand.

This is called the hour hand.

Time - AM/PM vs 24 Hour ClockNormally the time is shown as Hours: MinutesThere are 24 Hours in a Day and 60 Minutes in each Hour.Example: 10:25 means 10 Hours and 25 Minutes.

Very Important

Showing the Time

There are two main ways to show the time: "24 Hour Clock" or "AM/PM":

24 Hour Clock: the time is shown as how many hours and minutes since midnight.

AM/PM (or "12 Hour Clock"): the day is split into :the 12 Hours running from Midnight to Noon (the AM hours), andthe other 12 Hours running from Noon to Midnight (the PM hours).

Like this (24-hour above and AM/PM below it):

PM

AM

Ante Meridiem*Latin for "before midday“

(*Is that spelled "Meridiem" or "Meridian"?)

Post Meridiem*Latin for "after midday"

When: Midnight to Noon Noon to Midnight

24 Hour Clock: 0:00 to 11:59 12:00 to 23:59

Footnote on "Meridiem" vs "Meridian"Should "AM" be "ante meridiem" or "ante meridian" (likewise for PM)?The official (according to an American, Australian and British dictionary I checked), and most common spelling for AM is "ante meridiem" which is a Latin phrase. I recommend that spelling!But people sometimes use the phrase "ante meridian" (a "meridian" in this case refers to an imaginary line in the sky when the sun is at its highest point).

Converting AM/PM to 24 Hour Clock

For the first hour of the day (12 Midnight to 12:59 AM), subtract 12 HoursExamples: 12 Midnight = 0:00, 12:35 AM = 0:35

From 1:00 AM to 12:59 PM, no changeExamples: 11:20 AM = 11:20, 12:30 PM = 12:30

From 1:00 PM to 11:59 PM, add 12 HoursExamples: 4:45 PM = 16:45, 11:50 PM = 23:50

Converting 24 Hour Clock to AM/PMFor the first hour of the day (0:00 to 0:59), add 12 Hours, make it "AM"Examples: 0:10 = 12:10 AM, 0:40 = 12:40 AM

From 1:00 to 11:59, just make it "AM"Examples: 1:15 = 1:15 AM, 11:25 = 11:25 AM

From 12:00 to 12:59, just make it "PM"Examples: 12:10 = 12:10 PM, 12:55 = 12:55 PM

From 13:00 to 23:59, subtract 12 Hours, make it "PM"Examples: 14:55 = 2:55 PM, 23:30 = 11:30 PM

Comparison ChartHere is a side-by-side comparison of the 24 Hour Clock and AM/PM:

Example: on the hour Example: 10 minutes past

24 Hour Clock AM / PM 24 Hour Clock AM / PM

0:00 12 Midnight 0:10 12:10 AM1:00 1:00 AM 1:10 1:10 AM2:00 2:00 AM 2:10 2:10 AM3:00 3:00 AM 3:10 3:10 AM4:00 4:00 AM 4:10 4:10 AM5:00 5:00 AM 5:10 5:10 AM6:00 6:00 AM 6:10 6:10 AM7:00 7:00 AM 7:10 7:10 AM8:00 8:00 AM 8:10 8:10 AM9:00 9:00 AM 9:10 9:10 AM

10:00 10:00 AM 10:10 10:10 AM

11:00 11:00 AM 11:10 11:10 AM

12:00 12 Noon 12:10 12:10 PM13:00 1:00 PM 13:10 1:10 PM14:00 2:00 PM 14:10 2:10 PM15:00 3:00 PM 15:10 3:10 PM16:00 4:00 PM 16:10 4:10 PM17:00 5:00 PM 17:10 5:10 PM18:00 6:00 PM 18:10 6:10 PM19:00 7:00 PM 19:10 7:10 PM20:00 8:00 PM 20:10 8:10 PM21:00 9:00 PM 21:10 9:10 PM22:00 10:00 PM 22:10 10:10 PM23:00 11:00 PM 23:10 11:10 PM

Midnight and Noon"12 AM" and "12 PM" can cause confusion, so we prefer "12 Midnight" and "12 Noon".

What Day is Midnight?Midnight has another problem - there is nothing to tell you "is this the beginning or ending of the day".

Imagine you are told your friends are leaving for holiday at "midnight" on 12th March, what day should you arrive to say goodbye? Do you get there on the 11th (assuming they leave at the very start of the 12th), or the 12th (assuming they leave at the end of the 12th)?

It is better to use:11:59 PM or 12:01 AM, or23:59 or 0:01 (24-Hour Clock)

which the railroads, airlines and military actually do.So, if you see something like "offer ends midnight October 15th" tell them to use one minute before or after so there is no confusion!

Clocks

Clocks with Hands

CLOCKS CAN ALSO USE HANDS TO SHOW US THE HOURS AND MINUTES. WE CALL THEM "ANALOG" CLOCKS.THE LITTLE HAND SHOWS THE HOURS:

30 Minutesor Half-Past 15 Minutes

or Quarter-Past

The Big Hand shows the Minutes:                                 

2:30 orHalf-Past Two 5:15 or

Quarter-Past Five

Using both the Big Hand and Little Hand lets us know exactly what time it is:

1:11:35 AM

2:10:00 AM

3:8:35 AM

4:3:30 AM

Draw the hands on the clock

Digital Clocks

5 Hours and 8 Minutes

9 Hours and 36 Minutes

Digital Clocks show us the time using numbers. The number on the left of the : is Hours, and the number on the right is Minutes: