What is History? Webster: A chronological record of significant events (as affecting a nation or institution) usually of their causes Webster: A chronological record of significant events (as affecting a nation or institution) usually of their causes

What Is Time? Webster: the measured or measurable period during which an action, process, or condition exists or continues. Webster: the measured or measurable period during which an action, process, or condition exists or continues.

How do we measure time? SecondsMinutes Hours

DaysWeeks Years Centuries Decades Millennium

Calendars Is our calendar the only calendar? Aztec Calendar

Calendars Today’s date is 5760! Today’s date is 5760! If you went by the Hebrew calendar it would be. If you went by the Hebrew calendar it would be. It begins with the Creation, which is calculated to be 3,760 before the birth of Christ. It begins with the Creation, which is calculated to be 3,760 before the birth of Christ.

Calendars Today is 1378! Today is 1378! It would be if you went by the Islamic calendar. It would be if you went by the Islamic calendar. Theirs began with the year that Muhammad fled from Mecca. Theirs began with the year that Muhammad fled from Mecca.

Calendars Our calendar has its origin from the birth of Christ. Our calendar has its origin from the birth of Christ. It was designated “AD” for anno Domini, “the year of the Lord.” It was designated “AD” for anno Domini, “the year of the Lord.” The years before AD 1 were designated “BC” before Christ. The years before AD 1 were designated “BC” before Christ.

The Gregorian Calendar: Our Calendar In 1582 Christopher Clavius introduced our present calendar In 1582 Christopher Clavius introduced our present calendar It allowed for 365 days and a “leap year” every year that is divisible by four. It allowed for 365 days and a “leap year” every year that is divisible by four.

The Gregorian Calendar-- Our Calendar

Timelines: A Picture of Time A timeline is a chart that shows events in the flow of time, giving you a picture of how they relate to each other. Divide into even divisions depending on the length of time shown Events are linked to the timeline by lines to the point precisely where they occurred. Event 1 Event 2 Event 3 Event 4

September 11th Timeline 8:00 A.M. 9:00 A.M. 10:00 A.M. 11:00 A.M. 12:00 P.M. 1:00 P.M. 2:00 P.M. 3:00 P.M. 4:00 P.M. 5:00 P.M. 6:00 P.M. 7:00 P.M. 8:00 P.M. 9:00 P.M. American Airlines flight 11 crashes into north tower of World Trade Center United Airlines flight 175 crashes into south tower of World Trade Center President Bush speaks from Florida vowing to hunt down guilty parties American Airlines Flight 77 crashes into the the Pentagon FAA grounds all flights South tower of WTC collapses United Airlines flight crashes near Pittsburgh North tower of the WTC collapses New York Mayor Giuliani orders evacuation of Manhattan President Bush taken to Barksdale Air Force Base in Louisiana Bush boards Air Force One for Offutt Air Force Base in Nebraska, headquarters of the U.S. Strategic Air Command Seven World Trade Center collapses Bush arrives in Washington Bush addresses the nation U.S. military deploys missile destroyers and other equipment in New York and Washington