Why does the international date line exist

GEOG 101 Physical Geography

Lab 1: Scientific Method & Geographic Grid: Latitude, Longitude, and Time (Credit: R. Marston, Univ. of Kansas, UCSB Geography Department with modifications by D. Fairbanks and N. Sato)

Name ANSWER KEY Lab Day and Time Date

Materials and sources that will help you

• colored pencils • a globe • a piece of string • your textbook (chapters 1&2) • an Internet connection

Introduction: Physical Geography describes the planet Earth. It took humanity more than 10,000 years to discover that the Earth was round (spherical). Scientists use many methods in an attempt to understand natural phenomena. Some scientific discoveries represent purely theoretical ideas, while others may occasionally occur by chance. However, scientific knowl- edge is often gained by following a sequence of steps. In this lab we will explore the scientific method using natural hazards analysis. We will then move onto understanding the use of global grids and global time system. These are some of fundamental tools of geography and Earth system science. By the end of this lab you should be familiar with the following terms:

Key Terms: Antarctic circle (66.5° S) Arctic circle (66.5° N) Autumnal equinox Circle of illumination Circumference Coordinated Universal Time (UTC) Daylight saving time Equator (0°) Geoid Great circle Hypotheses International Date Line Latitude/Longitude Meridian Revolution around the sun (year) Parallel Prime meridian Rotation on an axis (day) Plane of the Ecliptic Scale Summer solstice Solar declination Standard Time Winter solstice Tropic of Cancer (23.5° N) Time zones Terminator Tropic of Capricorn (23.5° S) Vernal equinox Scientific Method

Section 1: Scientific Method—Hypothesis Testing GEOGRAPHY is the science that tries to describe, explain, experiment, understand and predict the spatial distribution of earth surface phenomena and the significance of those distributions to: 1) an understanding of places; and 2) an understanding of the relationships between society and natural phenomena. In short, geographers study “what is where, why, and so what.” PHYSICAL geography differs from HUMAN geography only in the relative emphasis given to natural phenomena (features, processes, and materials of the atmosphere, hydrosphere, lithosphere, and biosphere) compared to phenomena of human society (features, processes, and materials created by humans). Geography is further distinguished from the other natural and social sciences by virtue of the attention geographers give to three major themes: 1) SCALE refers to the recognition that how we view and interpret phenomena depends on the spatial extent and resolution of the measurements we collect 2) INTEGRATION refers to the recognition that the landscape functions differently as a whole than would be predicted by adding up the individual effects of climate, water, landforms and soil, plants and animals (i.e. the parts); and 3) SYNTHESIS refers to the attention geographers give to understanding the environmental opportunities (resources) and environmental constraints (hazards) on human activities, and on human impacts to the environment.

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Methods of Scientific Inquiry Scientists use many methods in an attempt to understand natural phenomena. Some scientific discoveries represent purely theoretical ideas, while others may occasionally occur by chance. However, scientific knowledge is often gained by following a sequence of steps which involve:

1. Questions (curiosity, identified problem) 2. Hypotheses (educated guess) 3. Collect data – Develop an experiment (observations, measurements) 4. Test hypotheses – arrive at a conclusion (accept/reject) 5. Predictions (further testing, hypotheses refined) 6. Theory (mathematical description, a logical explanation, or a proven model of the manner of interaction of a set

of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation)

7. Laws (repeated conclusions, universal, general principles) The first five steps are the most important for exploring and understanding the physical universe, and they represent what will be followed in this course and laboratory. The last two steps only become important after repeated questioning, observations, experimentation, and prediction.

Step 1. Establishing a hypothesis-a tentative, or untested explanation. A hypothesis is a proposition stated as the basis for argument or reasoning. Hypotheses are usually written in regard to a specific experiment that is to be undertaken. A hypothesis is usually expressed as a NULL HYPOTHESIS, that is, a proposition that a relationship does not exist between two variables. An example of a null hypothesis is:

“Additions of carbon dioxide into the atmosphere will have no effect on global air temperatures.” Because geographers are often concerned with spatial distributions, null hypotheses might be stated in terms like the following example:

“No difference exists between the rain water acidity in the Sierra Nevada mountain range and the Appalachian mountain range”

Step 2. Gathering data and conducting experiments to validate the hypothesis. Once the null hypothesis has been formulated, then the scientist collects and analyzes data to either confirm or reject it. The decision to confirm or reject a null hypothesis is usually based on statistical analyses of the data as well as providing some physical rationale. Step 3. Accepting, modifying, or rejecting the hypothesis on the basis of extensive data gathering or experimentation. If the null hypothesis is rejected, then the scientist has found that a relationship does exist between the variables. Your Task One group of environmental hazards affecting human activities are NATURAL HAZARDS, constraints on human activities created by features, processes, and materials of the atmosphere, hydrosphere, lithosphere, and biosphere. Natural hazards have distinct spatial patterns, so it follows that geographers will want to describe, explain, and predict the spatial distributions of natural hazards. The following simple inquiry should help you understand the scientific process. The purpose is to learn how to formulate and test hypotheses concerning spatial distributions of natural phenomena in physical geography. This will be accomplished by using maps of natural hazards in the contiguous 48 states in an overlay process to determine the “most hazardous” city from a set of three.

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1. Without having viewed any maps of the following natural hazards, select a minimum of four hazards—one from each Earth system group, based on those, which you would most wish to avoid if choosing a place to live. In the table below, list the three hazard maps you have selected. Hazards of the Atmosphere (Hazard Events 2001-2009) Severe Winter weather Severe storm/thunderstorm Extreme Heat Hurricanes/Tropical storm Tornado Hazards of the Hydrosphere Hazards of the Lithosphere Hazards of the Biosphere Drought Landslides – regional costly events Wildfire Flooding Seismic hazard – earthquakes

Hazard map (1) Hazard map (2) Hazard map (3) Hazard map (4)

One hazard has been selected each of the lists above, four total

2. Now formulate a null hypothesis concerning the distribution of your three combined natural hazards in reference to choosing from a set of three cities found across the 48 contiguous states you want to explore, i.e. which cities do you think would be most or least hazardous in relation to your combined hazards. Write your null hypothesis in the space below.

Last Name Location 1 Location 2 Location 3

A-B Sacramento, CA Austin, TX Augusta, ME C-K Phoenix, AZ Bismarck, ND Tallahassee, FL L-Z Olympia, WA Baton Rouge, LA Frankfort, KY

Example: “I believe that Sacramento will be the least hazardous city based on its mild climate. I have also not heard of many hurricanes tornadoes, or wildfires that have affected the city of Sacramento.” 3. Using the blank map of the USA attached at the end of this lab identify the locations of your three cities. Overlay your cities map on top of the hazard maps you have chosen to investigate and note if your cities are found within the hazard (present) or outside the hazard (absence). Treating each hazard layer as a code of 1 for presence you can add the overlaid areas to obtain the spatial pattern of the most hazardous cities scaled 0 for a city with none of your investigated hazards to 4 – maximum hazard.

Location Hazard 1 Hazard 2 Hazard 3 Hazard 4 Total

Answers will vary depending on your last name and the hazards you chose to work with.

4. In the space below, list the cities, in rank order from highest to lowest composite hazard ratings.

Answers will vary depending on the cities and the hazards you chose.

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5. Do your findings in #4 confirm or reject the null hypothesis you formulated in #2 above? Explain your reasoning. Example: Sacramento was actually not the least hazardous city. The data showed that it is more susceptible to earthquakes and tornadoes than I had thought. Based on this analysis Augusta was the least hazardous when considering the combined risks of all the hazards. 6. Consider the spatial scale and temporal measurement of the data you used. Explain, how these would affect your analysis. The data set just includes information from 2001 – 2009, which may fail to capture a lot of information (such as the recent drought in California). Also, the spatial data may be off—For example, the information is by county, but some counties in this country are a lot bigger than others, and thus the data may not truly reflect the diversity of what might be going on county-wide. Section 2: Getting a Grip on Global Grids Latitude is a north-south measurement of the angle formed between the equator, the center of Earth, and any point on its surface. Longitude measures the angle east or west from the Prime Meridian to any location on the planet. The Prime Meridian begins at the North Pole, and extends due south through Greenwich, England, before terminating at the South Pole. This meridian has been arbitrarily assigned a longitude of zero. Note that zero latitude, the equator, is not arbitrary at all, but is defined as the parallel exactly halfway between the poles. Together, latitude and longitude specify the exact location of a place on Earth. Latitude expresses a location’s relative north-south position, while longitude indicates its relative east-west position.

Locations from Section 1

Latitude (North) Longitude (WEST) Degrees Minutes Seconds Degrees Minutes Seconds

1 Olympia, WA 47 2.272 122 54.04

2. St Louis, MO 38 37.62 90 11.96

Section 2: It’s Time for Time We use temporal concepts all the time, yet seldom think about the origin of these terms. Time, as a measurement based on Earth motions, may be considered on an annual (yearly) or diurnal (daily) basis. The time of year is determined by the Earth’s position in orbit as it revolves around the sun. The time of day is determined as the Earth rotates (spins on its axis). Here’s an easy way to remember the difference:

One day is one rotation: Rodaytion (around the Earth’s axis)

One year is one revolution: Revolution (around the sun) Grab a Globe In this class, one theme we’ll see repeatedly is that many phenomena happen in an opposite way in the Southern Hemisphere compared to the Northern Hemisphere. Check your textbook for explanations of rotation and revolution, and let’s see if an observer in the Southern Hemisphere would see these phenomena differently from an observer in the Northern Hemisphere.

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Have one friend act as a sun (perhaps shining a flashlight on the Earth or an overhead projector), and have another friend spin the globe such that it rotates in the proper direction, with the sun rising in the east, and setting in the west. Watch the globe spinning from various perspectives – especially from above the poles. 2a) If you were hovering above the north pole, looking straight down towards the center of the Earth, would the Earth appear to rotate ( clockwise or counterclockwise ) below you? [Circle the correct answer.] Also viewing from above the north pole looking towards the center of the Earth, does the Earth appear to revolve around the sun in a ( clockwise or counterclockwise ) direction? [Circle the correct answer.] 2b) If you were hovering above the south pole, looking towards the center of the Earth, would the Earth appear to be rotating ( clockwise or counterclockwise )? [Circle the correct answer.] Also viewing from above the south pole looking towards the center of the Earth, does the Earth appear to revolve around the sun in a ( clockwise or counterclockwise ) direction? [Circle the correct answer.] 2c) Draw two diagrams: one for rotation, and one for revolution. Show the Earth’s axes, with both poles, the Earth’s direction of rotation or revolution labeled.

Rotation:

(Globe is tilted to the right, arrow showing rotation to the right)

Revolution:

(Image of earth revolving counterclockwise around the sun)

Your position on Earth relative to the position of the sun in the sky determines the local time of day where you are. The meridian on the Earth that is turned directly toward the sun is at the noon position. The meridian directly on the opposite side of the Earth is at the midnight position, while all other meridians fall somewhere between midnight and noon. All times of the day exist simultaneously, somewhere on Earth, and your time simply depends upon where you are at the moment. As you rotate with the Earth, you will experience all 24 hours of the day including each minute and each second of the day. There is a relationship between our global grids and temporal constructs that dates back to the Babylonians. Degrees are indicated with a ° symbol, angular minutes by a ’ and angular seconds with a ”. There are 360 degrees in a circle, 60 minutes in a degree, and 60 seconds in a minute. As there are 360° in a complete rotation, which takes approximately 24 hours, the Earth rotates by (360° / 24 hours) = 15° every hour. Because there are 60 minutes of time in one hour, and the Earth rotates 15° per hour, we can determine that it takes the Earth (60 minutes / 15°) = 4 minutes to rotate by 1°. STANDARD TIME ZONES: standard time zones have been established almost worldwide to avoid the confusion inherent with local solar time. Solar time differs by four minutes for every one degree of longitude. With standard time, the same time is assumed to exist throughout a zone that spans 15° of longitude. When crossing from one standard time zone into another, time changes by one hour. For example, in the adjacent zone to the east, the standard time is one hour later, while in the adjacent zone to the west it is one hour earlier. The zones are centered on controlling meridians which are 15° multiples: 0°, 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, 165°, 180°. Every point in a time zone assumes the same time as its controlling meridian. However, the zone boundaries are drawn in irregular shapes for convenience and/or political considerations. DAYLIGHT SAVING TIME, first proposed by Ben Franklin, is a concept that is simple enough but seems to continue to cause confusion on a semi-annual basis. Once a controversial subject, it is merely a manipulation of the clock for energy conservation and convenience. It does not make daylight any longer. It just shifts an hour of daylight from the morning hours to the afternoon hours so that we get a later sunrise and a later sunset. Most people benefit from it and favor it.

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In the summer when daylight is long, there is a significant period of daylight in the morning before people go to work that some would describe as “wasted” or at least not well utilized. When moving the clock forward one hour in the spring, we still go to work at 8 AM, but it is actually 7 AM by the sun. We get off work at 5 PM, but it is actually only 4 PM by the sun, and thus we have lengthened the period of daylight in the afternoon by one hour when most people can better use it. On the short winter days we do not have that extra daylight in the morning to manipulate, so we go back to standard time. Most of the United States observes daylight saving time from the second Sunday in March and to the first Sunday in November. The official changeover time is 2 AM on Sunday, so that it inconveniences the fewest number of people. The adage “spring forward - fall back” is good, but it is always better to understand why it is what time it is! Some places – like Hawaii and Arizona – do not use daylight saving time at all, and some other countries have different starting or ending dates for daylight saving time. Also, remember that the two hemispheres are always on opposite seasons (the Southern Hemisphere experiences winter during the Northern Hemisphere summer). For example, this means that some Southern Hemisphere cities will be on daylight saving time in January, when it’s winter in the Northern Hemisphere. 2e) When it is 8:00 PM daylight saving time, what time would it be if you were on standard time? _____7 p.m.________

2f) Is CSU, Chico currently on daylight saving time? _____YES_____ If yes, then put the day and time when your GEOG 101 lab section begins before the “PDT” below. If no, put the day and time when your GEOG 101 lab section begins before the “PST” below. Then, express the day and time using Coordinated Universal Time (UTC). - Pacific Standard Time, day: ________; time: _________ PST; add 8 hours to find UTC

- Pacific Daylight Time, day: _____TUES OR THURS______; time: ____2 PM_______ PDT; add 7 hours to find UTC

- Universal Coordinated Time, day: ____TUES OR THURS____; time: ____8:00 p.m._____ UTC

2g) Use the map below to find the day and time in other locations that correspond to the beginning of your GEOG 101 lab section by adding or subtracting from the UTC day and time that you just calculated above. Check online to determine if these locations are currently observing daylight saving, and apply it by adding one hour, where applicable. Put asterisks (*) next to the cities that are currently on daylight saving.

http://www.timeanddate.com/worldclock/

Place * Time Day Place * Time Day Phoenix, Arizona 2 p.m. same Montevideo, Uruguay 6 p.m. same

Denver, Colorado * 3 p.m. same New Delhi, India 2:30 am +1

Canberra, Australia 7 a.m. +1 London, UK 10 p.m. same INTERNATIONAL DATE LINE: The International Date Line falls in the middle of the Pacific Ocean where its inconvenience is minimized. When one crosses the Date Line the day and date must be changed, regardless of the hour of the day. This is necessary to keep the time observed on the other side of the line. Here’s how the IDL works:

When crossing from the west side of the International Date Line going eastward (toward the U.S.) 24 hours is repeated so that you gain a day: i.e. Friday becomes Thursday. When crossing westward (towards Japan) 24 hours is skipped; you lose a day and Monday becomes Tuesday. The same hour exists on either side of the Date Line, but on different days and dates. Standard time zones are handled as before. Notice that the –12 zone and the +12 zone each span only 7.5° and together make the 15°.

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2h) It is 5:00 PM, June 15th, Tokyo time. You are the drummer for a famous band and have a gig in Honolulu at 8:00 PM on June 16, Hawaiian time. You want to know how much time you have before the gig. Flight time has no effect on this answer. THERE ARE TWO WAYS TO SOLVE THIS PROBLEM. THE FIRST IS TO CONVERT ALL TIMES AND DATES TO UNIVERSAL TIME, as follows: First, using your textbook, or the figure above, convert all times and dates to UTC (UTC = “Universal Time = The current time in Greenwich (London): In other words, convert both Tokyo time and Honolulu time to London time so you can compare them! Time & Date (UTC):

This is the current time & date: (“Current time” = Standard Time =

Local Time)

5 PM, June 15, in Tokyo = 8 AM, June 15 in Greenwich (London)

How did I do this? The “World Map” table above states that: “Standard Time = Universal Time + value from table” BUT we already KNOW the Standard Time in Tokyo (5 p.m. June 15). So we need to change the equation around, solving for Universal Time: Universal Time = Standard Time – the value from the table The value from the table designates Japan with an “I”, or +9 hrs Solving: Universal Time = 5 p.m. June 15 – (9 hrs) Universal Time = 8 a.m. June 15 (aka Greenwich time)

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Time & date of the concert:

8 PM, June 16, in Honolulu = 6 A.M., June 17 in Greenwich How did I do this? Using the same equation as before: Universal Time = Standard Time – value from the table The value from the table designates Hawaii with a “W”, or -10 hrs Solving: Universal Time = 8 p.m. June 16 – (-10 hrs) Universal Time = 8 p.m. June 16 + 10 hrs Universal Time = 6 a.m. June 17

Tokyo is located within the zone I. The value for the zone I is 9. Modifying the expression of “Standard Time = Universal Time + value from table” (see the box within the figure above), Universal Time = Standard Time – value from table. Thus, the Coordinated Universal Time (UTC) for Tokyo at 5 PM, June 15 is 5 PM – 9 (hours) = 1700 hours – 9 hours = 0800 hours = 8 AM. Now, what zone is Honolulu located? W What value is the zone (of Honolulu)? -10 Universal Time = Standard Time (8 PM, June 16) – value for the zone (of Honolulu) (Watch out for the sign of the value.) Now find the difference between the top row (current time & date, in UTC) and the bottom row (time & date of the concert, in UTC). How many hours do you have before the gig?

In other words, what is the difference in time between 8 A.M June 15 and 6 A.M. June 17? Answer: 46 hours

2i) Explain why your answer for question 2h above is more than 27 hours.

Since you are going from East (Tokyo) to West (Hawaii) across the international dateline, you gain a full day (24 hours)

A SECOND, MORE DIRECT WAY TO SOLVE THE SAME PROBLEM is to note that while it is it is 5 p.m. June 14 in Tokyo, the clock in Hawaii is 19 time zones (=19 hours) behind, so it is 10 p.m. in Hawaii on June 14. From here we can calculate that the number of hours between 10 p.m. June 14 and 8 p.m. June 15 is 46. Section 3: Great Circles 3a) The shortest distance between any two points on the Earth’s surface follows the arc of a great circle. All great circles cut the Earth exactly in half. Where is the center point of any great circle on the Earth? How many different great circles exist on Earth’s surface?

Where? Middle of the Earth

How many? Infinite

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3b) Draw two simple diagrams: How many meridians (lines of longitude) trace a great circle path? What about parallels (lines of latitude) that are great circles?

How many of them follow a great circle path?

Meridians: All Parallels: The Equator only

Lines extend from pole to pole, they are NOT parallel to each other—They are

furthest apart at the equator.

Horizontal lines parallel to the equator

3c) Your instructor will use Google Earth to show the locations of Chico [approximately 40° N latitude (it’s actually at 39°43’] and Beijing, China [approximately 40° N latitude (it’s actually at 39°55’)]. Is the shortest distance from Chico to Beijing straight along the 40° N parallel?

Yes / No (Circle your answer) Now, your instructor shows the shortest path using Google Earth. Was your answer correct (or not)? Why was your answer correct (or not)? Explain. We often consider a flat map when looking at the shortest distance between two points, but the further you go from the equator, the more distorted distances become. When considering the spheroidal nature of the planet, the Great Circle Route is the most direct. 3d) Using Google Earth, identify the locations of Quito in Ecuador, and Kampala in Uganda [both are very close to the equator (0° latitude)]. Using the measuring tool of Google Earth, draw a line between these two cities. This is just one example of a great circle route. This is a straight-line path along the surface of the Earth that, if continued around the whole Earth, would form a great circle. There is exactly one great circle route that’s possible between any two points on Earth, and that great circle route will always be the shortest path between those two points. Will a great circle route drawn between them deviate wildly from the?

Yes / No (Circle your answer) How is this route different from the route between Chico and Beijing (both of which are located on the 40° N parallel)? The equator (0° parallel) is itself a great circle route.