1. Time Zones

3. Solar Time
In early days everyone set their clocks according to the sun. It was noon (12:00 p.m.) when the sun was at its highest point (its "zenith") in the sky.

4. In larger communities, the military often would fire off a gun to signal the noon hour and everyone would reset their watches. Or they would listen for the tolling of the clock in town hall.

5. Standard Time
In each time zone, everyone adopts the same time, and as you crossed from one time zone to another, you changed your watch by one full hour.

6. UTC Coordinated Universal Time
The worldwide standard for coordinated universal time, formerly known as GMT (Greenwich Mean Time), is now abbreviated as UTC (Coordinated Universal Time).
Some sources still refer to it as UTC/GMT and some web browsers, I.E. Mozilla, still display it as GMT.

7. Prime Meridian

9. Meet the Map The Prime Meridian is 0⁰ longitude
The International Date Line is 180⁰ longitude
Color coded time zones

11. Nunavut is spread across three time zones
Western Ontario uses Manitoba time
Southeastern corner of BC uses Alberta time
Eastern Quebec (directly south of Labrador) is on AST time throughout the year.

12. There were some other variations as well
There were some other variations as well. Newfoundland time is ½ hour different from the other Atlantic provinces.

13. THESE LONGITUDE LINES ARE 15° APART.
If it is 2pm in time zone A, what time is it in time zone B? B 7 A 6 2 3 4 5

14. If it is 9pm at location X, what time is it at location Y?

15. If it is 11am at location W, what time is it at location Z?

16. If it is 10am at location R, what time is it at location T?

17. Daylight Saving Time
Video: 4&NR=1

18. Why create the International Dateline?
If you could travel around the earth (to the east) in an instant, you would cross 24 time zones. Each time you would cross a time zone, you would move your clock up one hour. When you got back to where you started, you would be one DAY ahead everyone else!

19. The dateline is the 180 degree line of longitude, directly opposite the Prime Meridian.
Going east = subtract a day (you skip a day or lose time)
Going west = add a day (you’ve gained a day or added time)
Monday
Sunday

20. Meet the Map The Prime Meridian is 0⁰ longitude
The International Date Line is 180⁰ longitude
Color coded time zones

21. International Date Line