1. Time zones

2. Movement of the earth The earth revolves around the sun
The earth rotates on its axis
The earth is tilted on its axis 23.5○

4. Night and Day At any given time, half of the earth is in darkness
Images captured using Earth and Moon Viewer by John Walker and with satellite imagery provided by the Living Earth, Inc
Night and Day
At any given time, half of the earth is in darkness
? What season does this map show?

5. Day and Night
We experience day and night because we live on a rotating planet.
The day-night cycle is 24 hours long, because it takes 24 hours for Earth to complete a full rotation on its axis.

6. Sunrise Sunset Sun rises in the EAST Sun sets in the WEST
Direction of the earth’s rotation
Sun rises in the EAST
Sun sets in the WEST

7. Keeping time
Before clocks, people kept time using different instruments to observe the Sun’s zenith at noon.
The earliest time measuring devices we know of, are sun dials and water clocks.
 The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the 16th century BC.

8. Early time keeping What time is it?
(you are looking south at the pillar)

9. Early time keeping What time is it?
(you are looking south at the pillar)

10. Need for change
American railroads maintained many different time zones during the late 1800s.
Each train station set its own clock making it difficult to coordinate train schedules and confusing passengers.
Every city in the United States used a different time standard so there were more than 300 local sun times to choose from.

12. In a world of global travel
It is not convenient for every single place on Earth to keep its own unique time.
It is not convenient for every single place on Earth to world to be on the same time
11: : :05
3 in the afternoon?

13. Standardizing time
Various meridians were used for longitudinal references
The Greenwich Meridian was the most popular of these.
The Greenwich Observatory's reputation for the reliability and accuracy in publications of its navigational data was one factor that contributed to the Greenwich Meridian’s popularity.

14. Standardizing time
Sir Sandford Fleming was one of the key players in developing a satisfactory worldwide system of keeping time.
He advocated the adoption of a standard or mean time and hourly variations
He also helped convene the International Meridian Conference in 1884, where the international standard time system was adopted.

15. Standardizing time

16. Coordinated universal time (UTC)

20. Bizarre time zones

21. China
all of China has been standardized to Beijing time (UTC +8).

22. Newfoundland

23. Russia

24. Kiribati

25. Australia
During DST

26. Date line

28. Check….
If a plane departed at 4:00 pm on October 24 from Tokyo (approximately 135°E) and the flight takes 9 and a half hours, what time and date would the plane arrive in Los Angeles (approximately 120°W)?

29. The starting and ending points of the trip are 105° or seven time zones apart. When the plane took off from Japan at 4:00 PM on October 24, it was 11 PM on October 23 in Los Angeles. Adding 9 and a half hours to this, the landing time would be 8:30 AM on October 24.
Though it seems quite odd, this means that passengers can leave Japan in the afternoon on some date, fly for 9 and a half hours, and arrive in Los Angeles in the morning of the same date!

30. Daylight Saving Time

31. Summary or argument 10% summary Argument FCA: START sentence (5)
FCA: content vocab (5)
FCA: main ideas with relevant details (10)
Create a summary of the article “Daylight Saving Time”
FCA: Claim statement (5)
FCA: content vocab (5)
FCA: evidence to support claim (10)
Construct an argument justifying (or opposing) the continued use of Daylight Saving Time