We know that the measurement of time is read by a clock or a watch.
Any clock or watch except a digital watch, has a dial. On the circular
border of the dial of a watch or clock there are the hour numbers from 1
to 12 at equal intervals. Between the two numbers there are five
divisions. Each division represents a minute.
There are two hands of different lengths having one of the ends fixed at the center of the dial. The small hand is the hour hand and longer hand is the minute hand. The hour-hand moves slower than the minute hand. There is also a third hand called the second-hand. It moves very fast.
The hour hand makes one round of the dial in 12 hours. It moves
from one number to its nearest number in one hour, i.e., the hour hand
goes from 12 to 1 or 1 to 2 or 2 to 3, ........ etc., in one hour.
The minute hand makes one round of the dial in 1 hour. It moves
across one division in one minute or five divisions in 5 minutes.
If there is a second-hand, it makes one round of the dial in one minute, i.e. it moves across one division in one second.
On this basis we say:
1 hour = 60 minutes or 60 minutes = 1 hour
1 minute = 60 seconds or 60 seconds = 1 minute
1 hour = 60 minutes = 60 x 60 or 3600 seconds