Universe Cycle - Geography (5)
 Lab 

   
OBJECTIVES:
  • Discovering topographic maps.
  • Comparing and contrasting topographic maps.
VOCABULARY:
  • landscape
  • map
  • topography
MATERIALS:
  • road maps of local area
  • topographic maps of local area (optional)
  • 5 topographic maps per group

Students compare a series of topographic maps.


a flat landscape, contour lines will be far apart. 

BACKGROUND:

A map is a picture or representation of the Earth's surface. Maps show how things are related to each other by distance (both horizontal and vertical), direction, and size. Maps are a way of showing many things about a portion of the Earth's three dimensional surface on a flat piece of paper. This two dimensional representation can be carried and transported easily. A map is not a picture of the Earth's surface. Maps can show many things that pictures cannot show.

Topographic maps contain accurate information about vertical distances, or elevations, on the Earthís surface. As discussed in the Pre Lab, elevations are shown on topographic maps using contour lines. These are imaginary lines of equal elevation. The 0 foot contour line is always sea level. Contour lines are spaced at a regular contour interval, such as 25 feet.

Maps are smaller than the areas they portray: otherwise, they would be useless. Imagine a map of your city that is city-sized!. Distances on maps are thus smaller than the real distances they represent. The relationship between map distance and real distance is called a mapís scale. Topographic maps show two scales. A bar scale shows distances graphically. Topographic maps also have a fractional scale. This appears on the map as a ratio. This ratio tells how many real measurement units equal one of the same unit on a map. In the example in the diagram, the fractional scale is 1:100000. This means than one inch on the map equals 100,000 inches in the real world. This scale can be used with any measurement, such as inches, centimeters, or feet. The larger this scale is, the more area a map covers. For example, a map scale of 1:24000 covers a few miles: a map scale of 1:1000000 covers many states.

The details of these scales are more than most students can understand. The important point for them to understand is that maps accurately show the real world through mathematical ratios or scales.

PROCEDURE:

This lab can be customized to your local area if you have appropriate topographic maps. You would have to create a new lab sheet, but it would be worth the time. Also, the internet has more and more topographic maps available. This may be a good lab to do with computers.

  1. Compare a topographic map with a road map. Explain that a topographic map can show land features (landscape) and elevations (vertical distances), while a road map just shows human-made features and horizontal distances. You may wish to write a chart on the board, comparing topographic and road maps on the board. Here are some suggested differences:

TOPOGRAPHIC MAP

ROAD MAP

waterways
landforms
parks
forest
mountains

roads
buildings
boundaries
landmarks
street names

  1. Go over the topographic symbols with students.
     
  2. Give the students the 5 topographic maps or other maps you might be using. We have enclosed copies of the topographic maps, but they are not at the right scale. We highly suggest you purchase large maps for students to use. Maps can be purchased through the U.S. Geological Survey (www.usgs.gov under mapping). Have them compare and contrast the maps, and answer the questions on their worksheets. Don't give them too many hints about how to answer the questions. See if they recognize that although the topography on each of the maps is different, the maps all have the same color and symbols. This will be discussed in the post lab.

    ANSWERS using the maps suggested:

    1. Mt. Whitney
    2. Blue Lake, CA
    3. Laguna Beach, CA; Newark, CA, Joshua Tree South, CA, Blue Lake, CA
    4. Newark (1:24,000); Bluelake, CA (1:24,000); Superstition Mountain, CA (1:24,000); Laguna Beach, CA (1:24,000), Mount Whitney, CA 1:24,000
    5. Laguna Beach, CA [Newark, CA shows San Francisco Bay]
    6. Mt. Whitney, CA - 4416.9 meters, or 14494 ft [on Mt. Whitney, CA]
    7. Mt. Whitney, CA
    8. Newark, CA
    9. Mt. Whitney, CA
    10. Superstition Mountain, CA (the dotted blue lines mean a creek that is dry most of the time)
    11. Blue Lake, CA - the solid green shows forest
    12. Laguna Beach, CA
    13. Newark (1:24,000) flat, near San Francisco Bay; Bluelake, CA (1:24,000) many trees, lots of creeks, hilly; Superstition Mtn., CA (1:24,000) mountainous in the center, flat toward the north and south, vegetation during wet times; Laguna Beach, CA (1:24,000) near ocean, mountainous land, Mount Whitney, CA 1:62,500, very mountainous (highest in continental United States)

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