Lesson 15-The riddle of time Part Two Background Iformation W BT E ENTER
Lesson 15—The Riddle of Time W B T L E Part Two ENTER
Lesson 15-The riddle of time Background Information Contents 工 Development of Clocks 工工 Biological Clock I工 Calendars W BT E BAC
Lesson 15—The Riddle of Time W B T L E I. Development of Clocks II. Biological Clock III. Calendars Background Information
Lesson 15-The riddle of time . Development of Clocks--Sun Clocks Egyptian shadow clock Obelisk W BT E To be continued on the next page
Lesson 15—The Riddle of Time W B T L E To be continued on the next page. I. Development of Clocks—Sun Clocks
Lesson 15-The riddle of time .evelopment of Clocks--Sun Clocks Not until somewhat recently(that is, in terms of human history) did people find a need for knowing the time of day. As best we know, 5,000 to 6,000 years ago great civilizations in the Middle east and north Africa began to make clocks to augment their calendars. With their attendant bureaucracies, formal religions, and other burgeoning societal activities, these cultures apparently found a need to organize their time more efficiently. W BT E To be continued on the next page
Lesson 15—The Riddle of Time W B T L E Not until somewhat recently (that is, in terms of human history) did people find a need for knowing the time of day. As best we know, 5,000 to 6,000 years ago great civilizations in the Middle East and North Africa began to make clocks to augment their calendars. With their attendant bureaucracies, formal religions, and other burgeoning societal activities, these cultures apparently found a need to organize their time more efficiently. I. Development of Clocks—Sun Clocks To be continued on the next page
Lesson 15-The riddle of time . Development of Clocks--Sun Clocks x The Sumerian culture was lost without passing on its knowledge, but the Egyptians were apparently the next to formally divide their day into parts something like our hours. Obelisks(slender, tapering, four-sided monuments) were built as early as 3500 BC. Their moving shadows formed a kind of sundial, enabling people to partition the day into morning and afternoon. Obelisks also showed the years longest and shortest days when the shadow at noon was the shortest or longest of the year. Later, additional markers around the base of the monument would indicate further subdivisions of time W BT E To be continued on the next page
Lesson 15—The Riddle of Time W B T L E The Sumerian culture was lost without passing on its knowledge, but the Egyptians were apparently the next to formally divide their day into parts something like our hours. Obelisks (slender, tapering, four-sided monuments) were built as early as 3500 BC. Their moving shadows formed a kind of sundial, enabling people to partition the day into morning and afternoon. Obelisks also showed the year’s longest and shortest days when the shadow at noon was the shortest or longest of the year. Later, additional markers around the base of the monument would indicate further subdivisions of time. To be continued on the next page. I. Development of Clocks—Sun Clocks