1. Time Hess, McKnight’s Physical Geography, 10 ed. pp. 21-24
Lesson 3
Time
Hess, McKnight’s Physical Geography, 10 ed. pp

2. Local Sun Time
Time can be measured by the position of the sun in the sky
“Noon” is when the sun is directly overhead
This is known as zenith, when the sun is at the highest point in the sky

3. Local Sun Time, cont.
At a latitude of 40N
2011 Equinox, Sept 23

4. Problem 1
Problem: If it is noon where you are, would it be before or after noon for someone that is east of you?
After noon
Recall, the sun rises in the east and sets in the west
As you look down from the north pole, the earth would rotate counterclockwise
If the sun is just beginning to rise in California, then the sun would be near noon in New York, so…
As you travel east, time becomes later

5. Standard Time
To simplify things, 24 zones of standard time have been established internationally
As you move from one time zone to the next adjacent time zone, standard time changes by one hour

6. Standard Time, cont.

7. Standard Time, cont.

8. Standard Time, cont.

9. Standard Time, cont.

10. Time Zone Calculations
Standard time: 12:00 AM to 11:59 AM
12:00 PM to 11:59 PM
Military time/24-hour clock: 00:00 to 23:59
No AM or PM is needed
Regular time and military time…how do you convert?
If it’s before 1:00 PM, no need to convert
If it’s 1:00 PM or later, +12 to get military time
e.g., 1:01 PM + 12 = 13:01 military time
6:50 PM + 12 = 18:50

11. Time Zone Calculations, cont.
Greenwich Mean Time (GMT):
Runs through Greenwich, UK…recall which is 0° longitude
Established in 1884 (height of British naval dominance)
24-hour clock known today as the Universal Time Coordinate (UTC) or Zulu time
Used as a reference
If you know the current UTC time, you can figure out what time it is anywhere in the world

12. Time Zone Calculations, cont.

13. Time Zone Calculations, cont.

14. International Date Line
Located in the middle of the Pacific Ocean near 180° longitude.
If you cross the IDL from east to west, then it’s the next day (+1 day)
If you cross the IDL from west to east, then it’s the previous day (-1 day)

15. International Date Line, cont.

16. Daylight Savings Time
Used primarily in the U.S. to add an “extra” hour of daylight in the afternoon during spring/summer
Just remember, “Spring forward and Fall back”
Problem Part I, question 4:
Convert daylight savings time in KC to standard time by subtracting one hour, then continue to find the day/time in Ecuador

17. Sunrise/Sunset Time Corrections

18. Sunrise/Sunset Time Corrections

19. Map Scale Hess, McKnight’s Physical Geography, 10 ed. pp. 27-30
Lesson 4
Map Scale
Hess, McKnight’s Physical Geography, 10 ed. pp

20. Graphic Scales The distance on a map related to ground distance
Length on a map can be compared to the graphic scale to find true ground distance
Remains accurate if the map is reduced/enlarged

21. Fractional Scales
Map distance related to true ground distance in the form of a fraction or ratio
e.g. 1/24,000 or 1:24,000
This is to say that “one unit on the map is equal to 24,000 units on the ground”
Need a calculator and ruler
If map scale is enlarged or reduced, fractional scales will be inaccurate.

22. Fractional Scales, cont.

23. Large Scale vs. Small Scale
Many people think of this backwards…
Large scale maps show a small area of Earth in great detail
Small scale maps show a large area in less detail

24. Large or small scale?

25. large

26. Large or small scale?

27. small

28. Large or small scale?

29. small

30. Large or small scale?

31. large

32. Homework
Lesson 4, Part 1, Q5: Skip this question. There is no graphic scale listed on Map T- 1
Lesson 4, Part 1, Q6: Map T-9 can be found on pg 166 of your lab manual