Transparencies ch10-pp300-303

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Transparencies ch10-pp300-303

  1. 1. From Teaching Geography, Second Edition, by Phil Gersmehl. Copyright 2008 by The Guilford Press.Permission to photocopy is granted to purchasers of this book for personal use only (see copyrightpage for details).300
  2. 2. Teacher ’s Guide for Transparencies 10A and 10BThis map depicts Elmira, New York, a city that used to be an important producer of picturetubes and other TV components. The decline of U.S. television manufacturing hit Elmira hard.People lost jobs. Residents no longer had enough money for vacations or fashionable clothes.Ironically, conditions that hurt travel agents and clothing stores can help some other busi-nesses. For example, video-rental stores provide an inexpensive form of entertainment.Activity: Imagine that a company has asked for a permit to build a new video store. The yellowpages of the phone book show the locations of existing video stores (squares on the map). Askstudents to decide which circle is in a better location for a new store. There are several steps inthe process of using maps to analyze the potential market for something. The first two steps aredone for this example. 1. Find a basemap (a dot map of population is exceptionally good, if available). 2. Mark the locations of existing businesses that are potential competitors for the same cus- tomers. 3. Use a pencil and draw faint marks halfway between each pair of competitors. (If two are located close to each other, you might treat them as one location and give each one half of the customers in that area.) 4. Adjust the marks to ref lect other considerations (if desired): a. If products are of different quality, move the marks to give a larger share of the area to the business that appears to produce the better product. b. If transportation is not equal, adjust the marks so that the seller who has better access gets more area. c. If political or economic borders have an inf luence, adjust the marks to give more area to the seller who gains from that inf luence. d. If personal preferences or loyalties have an inf luence, adjust marks to give more area to the seller that customers seem to prefer. 5. Use those marks as starting points for dividing lines. These lines separate the people who are likely to go to one seller from those who are more likely to go to another. The goal is to make a map that shows the “territory” of each seller (see also the CD unit on Spatial Aura). 6. Count dots within the territory of each seller. Multiply the number of dots by the popula- tion represented by each dot. The result is an estimate of total population in the territory. 7. If you need a precise estimate, you could conduct a phone or mail survey to find out what proportion of the people in an area rent videotapes. The result is an estimate of the num- ber of customers a seller is likely to have at a given location.These maps and this Activity are adapted from ARGUS Activity N, which also has an extendedsimulation of the process of deciding where to locate expansion teams in major-league sports.Note that the activity teaches theory (location allocation) and a skill (market estimation) as wellas some facts about a specific place (Elmira). 301
  3. 3. From Teaching Geography, Second Edition, by Phil Gersmehl. Copyright 2008 by The Guilford Press.Permission to photocopy is granted to purchasers of this book for personal use only (see copyrightpage for details).302
  4. 4. Teacher ’s Guide for Transparency 10CTransparency 3L shows the land that was covered by ice sheets during the Pleistocene period ingeologic history. During that time of colder and wetter climate, lakes formed in many mountainand desert areas that are now dry and barren. As the ice melted, water often was trappedbetween the wall of ice and some high land. The high land may have been some hills thatstopped the ice from spreading further, or it may have been a moraine made by the ice as itpushed rocks and dirt ahead of it. Ice Age lakes of this type have an important common feature. They tended to trap sedi-ment. Here’s how: winds and streams brought dust and sediment into the lakes. That materialsettled to the bottom of the lake and filled in the deeper areas. When these lakes drained anddisappeared, the result was often a nearly flat plain.Activity: Put a few small objects into a bottle. Fill the bottle with muddy water and allow themud to settle. Ask students why the mud tended to settle into the low areas around the objects.Then ask what they would see if the water were all drained away.Activity: If you are lucky, a competition to set a new land speed record will take place in Utah atthe test track on the Bonneville Salt Flats during your class. Ask students why the test track isthere. The Bonneville Salt Flats are an exceptionally flat area that was covered by the ancientglacial lake, Lake Bonneville. The Great Salt Lake is a small remnant of this huge Ice Age lake(see the Transparency). Occasionally, heavy rains in the surrounding mountains will raise thelevel of the Great Salt Lake a few feet. This does not sound like much, but because the land isso flat, it can flood many square miles of land around the present lake (including the test track). Teacher ’s Guide for Transparency 10DActivity: The mostly straight-sided lake on this map is not an isolated case. Find satellite images,aerial photographs, or topographic maps for any of the former glacial lakes shown in Transpar-ency 10C (a good source is Google Earth or terraserver.com). Among the features you might seeon these maps are straight ditches, rectangular ponds, and other obviously artificial water fea-tures that were made as people tried to figure out how to live on an extremely flat plain. Thiskind of map-aided exploration of “ordinary” landscapes is a good complement for map-inter-pretation activities that focus on volcanoes, canyons, ski slopes, and other spectacular terrainfeatures. In this book I have said more than once that the ability to apply the information you can getfrom a broad-scale thematic map to a narrow-scale reference map (and vice versa) is one of thekey strategies for geographical analysis. This is the skill that makes information on thematicmaps both accessible and useful to those searching for the background they need to solve alocal problem. Learning to do this by using a faraway, exotic landscape is a way to focus on theskill without the emotional overtones and rhetoric that accompany a controversial local issue.Then, students can use the same skill to find information that can help shed light on a locallandscape puzzle or controversy. If students learned to do that, teaching geographical skills would really pay off! 303

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