1. Topic 2: MODEL OF EARTH

2. Topic 2: Model of Earth
Model- something that represents the properties or characteristics of something else.
Ex:
Scale- the ratio between the size of the model and the actual object.

9. Evidence For Shape of Earth
Ships mast example.
Altitude of polaris
Lunar Eclipse
*Pictures from space
* Best form of evidence

10. Earths’ Shape True Shape Oblate Spheroid “Slightly Squatty”
Equatorial diameter is greater than the polar diameter.
DIAGRAM
Apparent Shape
“Perfect sphere”
Models, pictures from space, scaled drawings

11. EARTH COMPONENTS Atmosphere- Thin layer of gases that surrounds Earth
*!* See pages 1 & 14 in Reference Tables
Hydrosphere- liquid water portion of Earths’ surface.
71% of Earths’ surface is covered by water.
Lithosphere- solid outer portion of Earth.
*!* See pages 1 & 10 in Reference Tables

13. ESRT Page 14

17. Finding Location
Coordinate system- grid system of lines for determining location.
Examples:

18. Latitude and Longitude
Angular distance north or south of the equator.
Maximum latitude=90o
Latitude = altitude of Polaris!
Longitude
Angular distance East or west of the Prime Meridian
Maximum longitude =180o
Longitude is calculated using the difference in local solar time and time at the prime meridian.

19. Finding Longitude:
Example: An observer measures the local solar time as 3 pm. The time at the prime meridian is noon. What is the observers longitude?

21. Practice
What is the Latitude and Longitude of the southern-most point of Australia?
What Continent is found at 40oS and 60oW?

23. Altitude of Polaris:
Diagram:

24. Practice
If the time at the Prime Meridian is 4pm and Local Solar Time is 12 noon, what is the observers longitude?

25. Practice:
What would the approximate altitude of Polaris be for an observer located in Watertown New York?

26. Practice:
What city in New York State is located at 43o 5’ N and 79o 0’W?

28. TIME ZONES

32. Field Mapping
Field- any area that has a measurable value of a given quantity at every point.
Examples: temperature, magnetic, gravitational, elevation.
Isolines- lines that connect points of equal field value.

33. Rules for Drawing Isolines:
Never cross or touch. (why?)
Tend to run parallel
Must end at the edge of the map or form a loop
“Smooth Curves”

36. Contour Lines

37. Isotherms

38. Isobars

39. Types of Isolines:
Isotherms-
Isobars-
Contour lines-

40. Interval- difference in field value between isolines.
Ex:
Gradient = Change in Field Value
Distance

41. Contour Mapping
Topographic map- Used to show the topography (shape) of the land.
Lines connect points of equal elevation.
Ex:
!*! See page 24 in the Review Book

43. Rules for Topo Maps
The closer the contour lines the steeper the slope.
Ex:

45. The V’s in the contour lines that form where they cross a stream point in the opposite direction that the stream flows.
Ex:

47. Hachures are used to show depressions in the topography.
Ex:

51. PROFILES:

57. In what direction does Maple Stream flow?