1. Longitude and Time

2. Imagine clocks did not exist…..what would you base time on?

3. Solar Noon
Sunrise
Sunset
Solar Time –
Solar Noon –

4. What did the early clocks look like?
Sundial

5. Review Longitude Lines

6. Do students in California get up when you get up for school?

7. Time = Longitude!!

8. Earth’s Rotation Earth Rotates ___o in 24 hours 360o/24hrs =
__o per hour

10. Standard Time Zones
What is the amount of time difference between each time zone?
1 hour
Every 15o longitude is a new time zone.
How many time zones are there?
24 hours in one day… there are 24 time zones!

11. Map of 24 Hour Time Zones
                                                                                                                        

14. Determining Longitude

15. 1st: -

16. A chronometer is a clock set to the local time at Greenwich, just outside of London.

17. 2nd: - Local time best found at Solar Noon (12 noon)
Sextant

18. 3rd: Multiply by -0/hr

19. 4th: -
If GMT is later in the day compared to local time – you are west
If GMT is earlier in the day compared to local time - you are east

20. East sees daylight first!
West last to see daylight!
Prime Meridian
Sun

21. 2pm is later in the day than 12 noon -
Example 1
GMT = 2 pm
Local Time = 12 noon
What is your longitude?
2 hours*15° = 30°
2pm is later in the day than 12 noon -
30°W

22. The Prime Meridian is later in the day than local time.
2pm
12pm
The Prime Meridian is later in the day than local time.

23. GMT = 8 am
Local Time = 12 noon
What is your Longitude?
-* -° = -° -

24. Final Question GMT = 10 pm Local Time = 12 noon
What is your Longitude?
-* -° = -° -
Final Question