Salt Lake Community College - Geography 1000Student Name ______

Quiz #1 June 11,2012A. J. Allred, Adjunct

  1. Which of the following describes the diameter of the earth?

a.C/π

b.8,000 times π

c.24,000 times π

d.24,800 divided by 7,900

e.C times π

Note: C = circumference, the distance all the way around the sphere, typically at its widest point. The equator is a circumference at the widest point of the earth’s sphere. D = diameter, the distance through the middle, typically connecting one side of the circumference to the other. The symbol π (pi) represents the relationship between the circumference and the diameter. Pi is a constant, a number that does not change. So, the formula for finding the diameter is D = C/ π.

If you get confused, just trying re-arranging these three symbols until it makes sense: C = D * π -- or π = C/D.

Or, try numbers: C = 24,900 rounded to 24,000 miles or just 24

D = 7,923 rounded to 8,000 miles or just 8

Π = 3.14159 . . . rounded to 3

So: 24 = 8 * 3

8 = 24/3

3 = 24/8

  1. Isolines:

a.Apply only to rainfall

b.Apply mainly to contour lines for land terrain

c.Do not apply to isohyets, isotherms and isobars

d.Apply to lines connecting any points of equal value

e.All of the above

Note: An “iso” line is a line of constant value – all measurements found on that line are the same.

  1. GPS compiles and compares layers of data, while GIS tells you where you are.

True ___False _X__

Note: GPS = global position system – position is where something is.

GIS = geographic information system – provides a database of information compiled in layers

  1. In the northern hemisphere, including Utah, north-facing sides of canyons typically hold more moisture than south-facing slopes.

True _X__False ___

Note: The sun is never straight-up overhead in Utah because we are at 40°N latitude. The sun is never vertical in the sky any further north or south than 23.5° latitude. So, the sun is always somewhere south of Utah. That means canyon walls facing north may never get direct sunshine. Canyon walls that are in shade tend to hold water and snow longer than the south-facing sunnysides.

  1. Which of the following lines follow “great circle routes” on the earth?

a.the equator

b.a line of longitude

c.a typical, unadjusted time zone boundary

d.any piece of string that you pull tightlyover a round globe

e.all of the above

Note: A “great circle route” is a portion of a full circumference, a line that goes all the way around a sphere at its middle, or widest place. Any piece of string pulled tight over the surface of a sphere is a portion of a ‘great circle.’

  1. A region that spans six time zones is:

a.About 90 degrees of the earth’s circumference

b.Roughly 33 percent of the earth’s circumference

c.About 60 degrees of longitude

d.None of the above

e.All of the above

Going east and west on the earth we mark time zones at major lines of longitude every 15°. So, a circle of 360 degrees would contain 24 times zones, each worth 15° of angle or distance. 360/15 = 24 hours in a day, or 24 time zones.

So, 90° of angle divided by 15° yields 6 time zones: 90/15 = 6. It takes the earth six hours to turn or rotate through six time zones or 90° of angle.

7. In Utah, the days start getting shorter in September.

True ___False _X__

In all the northern hemisphere, including Utah, the days start getting shorter after June 20. The longest day of the year for everywhere north of the equator is about June 20 – the summer ‘solstice’. September 20 represents the Fall ‘equinox’ when days and nights for the whole world are 12 hours each.

The shortest day of the year for Utah and the rest of northern hemisphere is December 21 – the winter ‘solstice’. After that, the days get longer until about June 20. Meanwhile, March 20 is the spring ‘equinox’ when days and nights are the same length.

In Utah, the shortest day (in December) shows about nine hours of sunshine and 15 hours of night. The longest day (in June) reverses that.

8. By simple interpolation, which of the following is the best estimate as to the surface speed of the earth’s rotation at about 30 degrees south latitude?

a. 1037 mph

b. 1,000mph

c. 670 mph

d. 130 mph

e. none of the above

If the earth’s rotation at the equator is about 1,000 miles per hour (one time zone per hour), then rough interpolation would show about 500 mph at 45° south latitude. Thirty degrees south latitude is somewhere in between, so interpolation suggests a speed of rotation that is also somewhere in between 500 mph and 1,000 mph.

Only answer ‘c’ fits that interpolation.

9. Summer occurs when the earth is closer to the sun in July.

True ___False _X__

Note: The earth is actually closer to the sun in July. The distance between earth and sun does vary, but doing is not very important.

10. If the time is 9:00 AM in Salt Lake City, then what time is it at 15°East longitude?

Note: Utah is in the 105°W time zone, which is seven hours west of Greenwich (GMT) -- 105/15 = 7.

A location at 15°E is one hour east of London (Greenwich), for a total of eight hours difference between SLC and 15 E longitude.

Because the east gets the sun before the west, the eight hour difference means that 15° E is eight hours ahead (later in the day) of Salt Lake City. So, add eight hours to 9:00 AM and get 5:00 PM at 15°E.