2) identify a major city (population greater than 50,000)

     2) Identify a major city (population greater than 50,000) within 1 degree of: (.5 point per location, total of 1 point)

                     34° N, 102° W

                     2° N, 45° E

Great Circles and Small Circles

             The geographic grid uses two types of circles–Great Circles and Small Circles.  All meridians and the equator are great circles where the plane of the circle passes through the earth’s center.  Any circle of smaller dimension that cannot through the center of the Earth is a small circle. 

            The geographic grid uses both kinds of circles, resulting in a major departure from the Cartesian Grid.  In the Geographic Grid scale (distance between numbered values) is constant in a north-south direction (for latitude), but varies in an east-west direction (for longitude).  See Table 1.

Table 1

            3)  Find the angular (distance in terms of degrees) and linear distance (straight line distance in terms of miles) between the locations in Table 2 based on the latitude and longitude scales in Table 1.  Be sure to calculate shortest linear distances! (.5 point per distance in box, total of 3 points)

Table 2

Local (Solar) Time and Standard Time Zones

            Local or Sun or Solar time is based on the position of the earth’s surface relative to the sun.  In the 18th, 19th and early 20th centuries Marine Chronometers were used to determine longitude based on differences in solar times on board the ship and some reference location like Greenwich.  As a general rule going west means subtracting hours, going east means adding hours.  Add a day if crossing from west longitude across the International Date Line.

            4)  Calculate the differences in local time or solar time between the following locations. (1 point each, total of 3 points)

a) If it is 3:00 pm on Wednesday in Erie, USA (80° W) what time is it in Cardigan, UK (5° W)?

b) If it is 11:00 am in Seattle, USA (122° W) on Monday what time is it in Tripoli, Libya (13° E)?

c) If it is 1:50 pm on Thursday in Jakarta (107° E) what time is it in Wellington, NZ (174° E)?

World Standard Time

            To avoid confusion, governments have standardized time zones to avoid the confusion of a plethora of different local times.  Standardized time zones are based on 7.5° swaths or bands on either side of a standard meridian that is a multiple of 15°.  Not all countries or states for that matter conform to these time zones.

         5)  Answer the following.  (2 points)

a)  How many standard time zones are there in the United States (all 50 states)?

b)  What is the estimated local time in Perth, Australia (116° E) if the local time is 7:00 am in London, UK (1° E) on a Monday morning.  What is the standard time in Perth when the standard time in London is 7:00 am?

Earth-Sun Relationships

            Earth-Sun relationships are important in understanding climate and weather patterns.  Variations in the amount of solar energy at the earth’s surface are a direct consequence of the earth’s position and orientation in orbit.  Variations in the angle of intercepted solar radiation, and differences in daylength are responsible for seasons. 

         6)  Label in Figure 1 where each of the following occurs (3 points):

                        a) aphelion

                        b) perihelion

                        c) vernal equinox

                        d) autumnal equinox

                        e) summer solstice

                        f) winter soltice

    7)  Indicate in Figure 1 where noon, midnight, sunrise and sunset occurs on the diagram for the autumnal equinox with the letters N, M, R, and S (2 points).

8) At what points in the Earth’s orbit (or dates on the calendar) are daylengths the same at all latitudes? (1 point)?

Figure 1

9) At which of the following locations would experience the greatest amount of time in the circle of illumination (i.e. daylight) on July 7? (1 point)

            59° N, 107° E

                35° N, 32° E

                0°, 0°

                                60° S, 67° W

10) At which of the following locations would experience the greatest amount of time in the circle of illumination (i.e. daylight) on January 6? (1 point)

            55° N, 115° W

                37° N, 27° E

                0° , 15° W

                45° S, 78° E