Download Metr101Lab1

Metr 101-02 – Fall 2009
Lab #1
Latitude, Longitude, & Time Zones
Due Tuesday 9/1/09
(40 points total)
Name: ________________________________________________________
Introduction
We will use this lab session to become acquainted with the concepts of latitude,
longitude, and time zones.
Task #1: Latitude and Longitude
Latitude: is the angular distance of any point on the surface of the earth north or south of
the equator. The equator is latitude 0°, and the North Pole and South Pole are latitudes
90°N and 90°S, respectively. The length of one degree of latitude averages about 69 mi
(110 km); it increases slightly from the equator to the poles as a result of the earth's polar
flattening. Latitude is commonly determined by means of a sextant or other instrument
that measures the angle between the horizon and the sun or another celestial body, such
as the North Star. The latitude is then found by means of tables that give the position of
the sun and other bodies for that date and hour. An imaginary line on the earth's surface
connecting all points equidistant from the equator (and thus at the same latitude) is called
a parallel of latitude. On most globes and maps parallels are usually shown in multiples
of 5°. Because of their special meanings, four fractional parallels are also shown. These
are the Tropic of Cancer (23 1/2°N) and the Tropic of Capricorn (23 1/2°S), marking the
farthest points north and south of the equator where the sun's rays fall vertically, and the
Arctic Circle (66 1/2°N) and the Antarctic Circle (66 1/2°S), marking the farthest points
north and south of the equator where the sun appears above the horizon each day of the
year. Generally speaking, what we know as the tropics is the area of the world located
between the tropics of Cancer and Capricorn and the polar regions are bounded by the
Arctic and Antarctic circles. Another way of describing the different latitudes is by
referring to the high latitudes in either hemisphere as being higher than 60, the middle
latitudes as being roughly between 30 and 60 and the low latitudes as being lower than
30. The equatorial region is the area within a few degrees of latitude from the equator.
Longitude: is the angular distance on the earth's surface measured along any latitude line
such as the equator east or west of the prime meridian. A meridian of longitude is an
imaginary line on the earth's surface from pole to pole; two opposite meridians form a
great circle dividing the earth into two hemispheres. By international agreement, the
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meridian passing through the original site of the Royal Greenwich Observatory at
Greenwich, England, is designated the prime meridian, and all points along it are at 0°
longitude. All other points on the earth have longitudes ranging from 0° to 180°E or from
0° to 180°W. Except where it is changed to account for populated areas, the International
Date Line lies along the 180° meridian. Meridians of longitude and parallels of latitude
together form a grid by which any position on the earth's surface can be specified.
Task 1 (16 points total)
For the list of cities below, write their latitude and longitude. Try using Google Earth.
Search for different locations by using the “Fly to” search bar on the upper left hand
corner of the screen. The latitude and longitude are displayed just below the main image.
Please round to one decimal point(ie, 49.3 N degrees North, 25.3 W).
Table 1
Latitude (N or S)
Longitude (E or W)
San Francisco, California
Denver, Colorado
Chicago, Illinois
Miami, Florida
Paris, France
Baghdad, Iraq
Bangkok, Thailand
Tokyo, Japan
Task # 2- Time Zones
Time zones: Since the earth rotates about its axis once every 24 hours and one full
rotation is equal to 360 degrees of longitude, the earth moves through (360/24=15) fifteen
degrees of longitude every hour. This means that you can divide the earth into 24
different wedges, each wedge being 15 degrees of longitude wide and centered at the
prime meridian, 15W, 30W, 45W, etc. These wedges are known as time zones.
Every location on the earth located within a time zone has the same local time. By
convention, each of the 24 time zones was originally denoted by a letter of the alphabet.
The letters begin with the time zone just to the east of the prime meridian and increase by
one letter as you move east from there. The time zone centered at the prime meridian is
known as the “Z” time zone and is occasionally referred to as “Zulu” time. The proper
way of referring to the local time at the prime meridian is by using “UTC” (Universal
Time Coordinates) after the time. For example, if you see “18UTC” or “18Z” that refers
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to 6pm local time at the prime meridian (which passes through Greenwich, England)
Figure 1 shows the world’s time zones as of June 2004. You will notice that the
boundaries of time zones do not necessarily follow straight lines along meridians. There
are many “wiggles” in the time zone boundaries that have been made to accommodate
political boundaries. For instance, the European countries have decided to keep most of
Europe in the same time zone, to make it easier for commerce. Some places have decided
to have special time zones of their own, so there are indeed “I” and “O” time zones. All
the time zones of the world are detailed in the inset shown in Figure 1.
Task 2 (24 points total)
For this task, calculate the local time and day of the week assuming 24 uniform time
zones(15 degrees of longitude per time zone).
When it is 18Z on Wednesday, the local time and day of the week is:
In San Francisco, California
In Denver, Colorado
In Chicago, Illinois
In Miami, Florida
In Paris, France
In Baghdad, Iraq
In Bangkok, Thailand
In Tokyo, Japan
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