1. Models of the Earth

2. Roundness of Earth Evidence:
Photographs from space
Objects over horizon
Earth shadow on eclipse
Altitude of Polaris
Shadow angles at different parts of the world
The name for the shape of Earth is oblate spheroid
Results in differential gravity; greater distance at equator = less gravity

3. Eratosthenes Method
Watch how shadow length varies with the angle from the sun!

4. Lab: Earth’s Circumference
Calculate the size of Earth using your own data! Amazing!
S = L C

5. Test of the day: 9/23
Given 360° longitude (180 E, 180 W) and Earth rotates 1x/day (24 hours), how fast is Earth spinning?
What is this speed in Rochester?
L=cos(Lat)*EqLong
Our lat = 43.13°, EqLong = mi
Speed = 15 * L (because of your rotational speed calculated above)
=683 mph!!

6. What do you think? 9/25
At what altitude would Polaris be if you were at 30° N?
What does gradient mean?
(don’t just give the formula, you geek)
How many labs do you owe? Turn them in.

7. Latitude and Longitude
Used for measuring Earth
Useful in providing accurate locations on a sphere
What is the basis of latitude?
What is the basis of longitude?
Who came up with this, anyway?
1884, Washington DC conference

9. What is the fastest way to get from NYC to Madrid?

11. What is a Field Map? Map indicating measurement of some value
What kind of value?
Temperature
Elevation
Election results
Strength of manure odor

12. Fields, Isolines, and Gradients, Oh MY!!
A field is just an area of space.
A soccer field
A topographic quadrangle
A continent
Isolines connect points of equal value within the field
Contour lines are special kinds of isolines, connecting points of equal elevation
Gradient is just how steep an area is, and can be estimated by observing how close together isolines are. Formula for gradient is change in field value divided by distance.

13. Fields
Field values can either remain constant (static) or change (dynamic)
Static: elevation
Dynamic: grades
Field values can either be just a number (scalar) or show a direction (vector)
Scalar: temperature
Vector: migratory patterns of European swallows
But, is it unladen?

14. Isoline RULES!!!! Isolines may NEVER cross
Isolines connect points of equal value
Isolines either entirely close upon themselves…. OR go off the map

15. Find a high or low in the center
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480

16. Insert points where needed
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17. Connect your points
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18. Reminders 10/1
How do you record measurements of latitude and longitude?
How does a topographic map distinguish areas of steep gradient from gentle gradient?
What is the latitude of NY?

19. Topographic Maps What do they have on them? Scale Elevations Roads
Buildings
Railroads
Name
Date
Nearby maps

20. Hachure Lines Show enclosed topographic depressions, such as
Sinkholes
Volcanic craters
Meteor craters
Are illustrated with a contour line with small marks on the inside of it.
The elevation is the same as the previous contour line.

22. How to Make a Profile Align scrap paper along profile line
Mark starting and ending points
Mark contour lines on scrap
Move scrap over to profile sheet
Follow marks up to elevation indicated, mark on profile sheet
Connect the dots, La-la-la

23. A
500
460 B
480
500
CI = 20 ft

24. Voila! Transfer points straight up to their elevations
Connect the dots, la-la-la!
580
Enclosed depression
560
540
520
River
500
480
460
440
500
460
480
Voila!

25. 10/3
Calculate the elevation gradient between my house and this school, given that my house is 436 ft and the elevation of the school is 486 ft. The distance between them is 5.6 miles.
-units?
How many different 20-foot contour lines do I cross when I ride my bicycle to school?
LTI in your network drive???

26. How to Read Quadrangles
What is a quadrangle?
What information is around the map?
How is the map oriented?
What scale am I looking at?
How to use rectangles 1-9

27. Topographic Map Symbols
Check out this radical sheet!

28. Things I noticed… Parallel = latitude Meridian = longitude
Quadrangle locator map
3 different Norths
Geographic
Polaris
Magnetic
Declination is the angle (also shown in Mils!)
Lat/Long vs UTM coordinates
Contour lines form a V, pointing upstream
Ratio scale (1:24000) is unitless

29. Comments from Lab
What is the highest possible elevation?

30. Comments from Lab
What is the latitude/longitude of Rochester?

31. Comments from Labs
As the difference in field value increases between two spot locations, the isolines move closer together
Labels for gradients
Hachure marks show enclosed depressions
Depression contours are the same elevation as the previous contour

32. Other Map Comments…
What is a scale? How many different kinds do we use?
Streams create V-shaped contours, POINTING UPSTREAM
What is declination? Mils?!?
From military-net.com, “there are 6400 mils in a circle”
Profiles from volcano lab are sloppy! Make them … curvaceous, ooh-la-la!

33. 10/7
Sketch a stream flowing southwest, crossing at least three contour lines
What does “contour interval” mean?

34. Lab List and “Lessons Learned”
Lab 5: Earth’s Circumference
Size of Earth is approx 40k km
Using Eratosthenes method
Ratio of angle and 360 = ratio of distance and circumf.
Lab 6: Latitude and Longitude
How to use coordinate systems
Altitude of Polaris = your latitude
Prime Meridian, equator, N/S poles, int’l date line

35. Lab 7: Constructing a Field Map
What isolines are, isotherms, contour lines
Isoline rules (extend to edge, circle back, don’t cross)
Calculating gradient
Visually identifying steep/gentle gradient
Lab 8: Constructing a Contour Map
Contour lines connect points of equal elevation
Hachured lines for depressions
Constructing profiles
V-shape when crossing streams, points upstream

36. Lab 9: Topographic Maps Quadrangle map reading skills, lat/long
Declination
Rectangles
Spot elevations (benchmarks)
Contour intervals, man-made structures
Scales (ratio, bar)
Nearby locations

37. Topics and Tasks Earth’s size Earth’s shape Earth’s spheres
Atmosphere
Hydrosphere
Lithosphere
Using ESRT!
Eratosthene’s method
FORMULA!
Latitude/Longitude
Using Polaris
Labels!
Field maps
Drawing Isolines
Topographic maps
Drawing Profiles
Gradient
Formula
Spacing of contours
Units!
Streamflow
Relationships: As 1 variable increases, what happens to the other variable?
How to tell Lat/Long without a direction- which way is increasing?

38. And more… Contour Interval is the elevation change between contours
Labels for degrees, minutes, seconds
Include N/S for Latitude, E/W for Longitude. (the US is North and West!)
Units!
Using the ESRT
Making profiles
Eratosthenes Method
Sketch a profile v.
Create/Draw a profile

39. A B
500
CI = 20 ft

40. 580
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