you need
• - calendar,
• - Watch
Guide
1
Now, as before, the basic unit of timing are per day, which is equal to one cycle of rotation of the Earth aroundits axis.Once they were arbitrarily divided into 24 hours, an hour - 60 minutes, a minute - 60 seconds.Now, in order to determine how much time is enough to look at the clock.Mechanical or electronic, being properly and in time reconciled, they will show you the exact time .
2
However, day - not much time unit.Watching the change of phases of the moon, people have found that the length of the month - 28 days.And, despite the fact that the count was not qu
ite accurate, we still use the values ​​produced by this unit of time - a week, consisting of 7 days.
3
Since the division of the year into months in our calendar is quite arbitrary, different months have different numbers of days - from 28 to 31. Year - value is also not very accurate.We live by the calendar, in which three of the four years are 365 days, and the fourth, because of an error, - 366.
4
Not so long ago in our country have been taken, such as the timing unit five-year planand a decade.Currently time they are used much less often, however, these values ​​can be found in the pages of history textbooks, which tells about the events of the twentieth century.
5
also in the history books you can find such values ​​as the century, century and millennium.These time intervals can be divided human civilization, which has just a few thousand years.Speaking of human century, it means 70-80 years.And talking about the age of our planet and stars, such values ​​should be used as the millions and billions of years.