Measuring and Organizing TIME Tools of the Historian Measuring and Organizing TIME

How Do We MEASURE Time? To study the past, historians must have a way to identify and describe when things happened. They do that by measuring and labeling time in different ways.

Calendars We rely on calendars, or dating systems, to measure time. A calendar arranges days in order.

Cultures throughout the world have developed different calendars based on important events. Aztec Calendar Mesopotamian Calendar Ancient Egyptian Calendar Greek Calendar

Calendars Different cultures in the world have developed about 40 different calendars. Some cultures developed calendars based on nature, such as the cycle of the moon. The Chinese, Jewish and ancient Egyptians are some of these cultures.

Calendars: many are based on events of religious importance Christian Calendar birth of Jesus Jewish = 3,760 years before the Christian when they believe the world was created Muslims = begin with the time when their leader, Muhammad, left the city of Makah for Medina; 622 years after the birth of Christ

We use this Calendar as does most of the world. What calendar do we use? The calendar we use today is based in part on a calendar developed by Julius Caesar a Roman leader. The calendar is called the Julian calendar. (365.25 days/year with a leap year every 4th year). It was revised in 1582 by Pope Gregory XIII to start counting with the birth of Jesus Christ. We use this Calendar as does most of the world.

What Calendar do we use in today in the United States? Answer on your white board

Why are calendars different from culture to culture? Answer on your white board…

Dating Events The years before the birth of Jesus are known as “B.C.” or before Christ. (To avoid religious references in dating many historians prefer B.C.E. “before current era”) The years after are called A.D. or “anno Domini” a Latin phrase for “in the year of our Lord.” (Current books are beginning to use C.E. “current era”)

Dating Events To date events before the birth of Christ, or B.C., we count backwards from A.D. 1. There is no year “0” The year before A.D. 1 is 1 B.C. (Notice that “A.D.” is written before the date, while “B.C.” is written following the date.) We often times leave A.D. out all together, so if a date is shown with neither A.D. or B.C. we assume that it is A.D. To date events after the birth of Christ, or “A.D.,” we count forward, starting at A.D. 1.

What do “B.C.” and “A.D.” mean? Answer on your white board…

Answer on your white board… What year came after 184 B.C.? Answer on your white board…

What do “B.C.E.” and “C.E.” mean? Answer on your whiteboard

How do we ORGANIZE Time? One way to measure and organize time is to label groups of years. Dividing it into blocks of time. For example, a group of 10 years is called… a decade.

Periods of History Historians divide history into blocks of time known as periods or eras. A period of 10 years = decade A period of 100 years = century A period of ten centuries = Millennium

Periods of History Centuries are grouped into even longer time periods known as eras, which are given names. Prehistory is the first of these long periods Prehistory: the time before people developed writing (beginning – 5,500 years ago) Ancient History: ending c. A.D. 500 (c., or circa, means “about”). Middle Ages (medieval period): the next thousand years c. A.D. 500 – c. A.D. 1500 Modern History begins from c. A.D. 1500 and continues to the present day.

When Did It Happen? One way historians tell or write a story of the past is to put the events in the order in which they happened. Time order is called chronology. What root words do you see in chronology?

Time Lines : Tools to help you Organize Time! A time line is another way to track the passage of time. A time line is a diagram that shows chronological events or order of events within a period. Most time lines are divided into sections in which the sections are evenly spaced. Events are placed on a time line at the date when the event occurred.

Timelines Sometimes the spread of time may be too long to show all the years in even spaces. To save space, a period of time may be omitted or left out from the time line. Where this happens, a slanted or jagged line appears on the time line to show a break in the even spacing of events.

There are different types of time lines:

It is your turn! Remember our Social Studies theme? Continuity and Change You will create a timeline of your life that highlights the changes that have taken place. On the back you will make a list of three things that have continuity. You may want to discuss this with your family and see what is the same today as it was for them in the past.