Time

Time is the ongoing sequence of events taking place. The past, present and future.

Time is measured  using seconds, minutes, hours, days, weeks, months and years.

Clocks are used to know time

#### Below are images of Clocks

Time is shown as Hours: Minutes

A Day has 24 Hours and each Hour has 60 Minutes

Time can be Am or PM

Look at the Clock below:

#### Play the below video to learn when its AM or PM

Any time before Midday is refered to as AM i.e from Midnight to Noon.

Any time after Midday is PM i.e from Noon to Midday

Study the image below carefully.

The common units of time include:

1. Second(s)                60seconds = 1min

2. Minutes (min)          60mins = 1hour

3. Hour (h)                  24hours = 1day

4. Day                         7days = 1week

5. Week                       4weeks = 1month

6. Month                    12 months = 1 year

7. Year(yr)                 365days = 1year

Months with 31 days are January, March, May, July, August, October and December.

The rest have 30 days each except February which has 28 days but 29 days in a leap year.

## The 12 h and 24 h – system

In the 12 h-clock system, the day is divided into:

a.m (Ante-Meridian or Before noon)

and p.m (Post-Meridian or afternoon).

In the 24 h-system time is written in four digits.

The first two digits indicate hours and the last two digits indicate minutes past the hour.

Before noon, the time rages from 0000 h(mid night) to 1159 h (just before noon).

From noon, the time ranges from 1200 h to 2359 h (just before midnight).

When converting from 12 h system

1.00 a.m.

would be 0000 h + 0100 = 1100

but 1.00 p.m.

would be 1200 h + 0100 = 1300 h

## Work this out

Suresh arrived at his shop at 7.40 a.m. He worked for 1 h 30 min before going for tea break.

He came from tea break at 10.30 a.m and went for lunch at 1.35 p.m.

#### Work out

(a) time he went for tea break in a 24-hour system).

(b) time he spent for his tea break.

(c) time he worked after tea break.

(d) time he went for lunch in 24-hour system.

#### Solution

(a) Arrival time ………… 7.40 a.m

Time spent working …… 1 h 30 min

7.40 + 1.30

Time break starts 9.10 a.m

in 24-hour system 0000 h + 0910 = 0910 h

(b) Time spent on tea beak 10.30 – 9.10  = 1.20 = 1 h 20 min

(c) Time he worked after tea break

Start time 10.30 a.m

Lunch time 1.35 p.m

10.30 a.m to 12.00 noon = 1 h 30 min

12.00 noon to 1.35 p.m = 1 h 35 min

Total time worked from 10.30 a.m. to 1.35 p.m. = 3 h 5 min

(d) Lunch time was 1.35 p.m

= 1200 h + 0135 h

= 1335 h (in 24-hour system)

## 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), and
• the other 12 Hours running from Noon to Midnight (the PM hours).

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

#### Can you tell the time on this clock?

Is it AM or PM?

Can you write it in 12 hour and 24 hour systems?

### Sources

• different-clocks by

elimu

used under CC_BY-SA
• Time_img1 by

Various sources

used under CC_BY-SA
• Time_img2 by elimu used under CC_BY-SA
• Learn_to_tell_the_time__The_difference_between_AM_and_PM_1 by Unknown used under CC_BY-SA
• 7df5f639-d977-44e8-947f-67a7d5222655 by elimu used under CC_BY-SA
• Time_img5 by elimu used under CC_BY-SA
• Time_img6 by

installer.com

used under CC_BY-SA
• Time_img7 by elimu used under CC_BY-SA
• time_img9 by Rising berry used under CC_BY-SA
• 68df4831-c9be-43bd-9127-81d3748ef315 by elimu used under CC_BY-SA
• Time_img11 by skwirk used under CC_BY-SA