Calendars

A

calendar

measures

time

in

years,

months,

weeks

and

days.

Our

calendar

was

developed

over

thousands

of

years.

In

ancient

times,

people

kept

track

of

time

by

watching

the

regular

patterns

of

the

Sun

and

Moon.

They

scratched

lines

into

calendar

sticks

made

of

wood

or

bone

to

mark

the

passing

days,

months

and

years.

About

5000

years

ago,

people

started

creating

lunar

calendars,

which

are

based

on

the

phases

of

the

Moon.

Every

29.53

days

(about

one

month),

the

Moon

travels

all

the

way

around

the

Earth.

Twelve

of

these

cycles

make

a

lunar

year,

which

is

354.36

days.

A

calendar

based

on

the

lunar

year

is

called

a

lunar

calendar.

The

Babylonians,

Chinese,

Greeks,

Romans

and

Egyptians

used

lunar

calendars.

An

ancient

calendar

stick