Topographical Maps, Contour Lines and Profiles
Summary
In this mapping field lab students determine the elevation of a given object in a designated area on our school campus using cartography tools. They will draw and write about their procedure. Students will then continue the use of these tools to create a contour map of the area. With the knowledge students have acquired, they will interpret contour lines from a professional map of our county.
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Learning Goals
This activity is designed to help students discover and explain how contour lines show elevation and landforms on a map as well as how the relief of an area determines the contour interval used on a map. Students will also come to understand the basic rules of contour lines. To achieve these goals, students will make observations, propose problem-solving strategies, and work in cooperative groups to implement their plan. They will learn to use an abney level and a stadia rod to collect data. They will then create a topographic map of the given area. After the lab, students will create a topographic profile of the study area. To close, students will use a topographic map of our county to learn more about the area they live in.
Key vocabulary:
topographic map
elevation
contour line
contour interval
relief
index contour
map scale
map legend
Key concepts:
1. Contour lines never cross. All points along contour line represent one elevation.
2. The spacing of contour lines depends on slope characteristics. Contour lines that are close together show a step slope. Contour lines that are far apart show a gentle slope.
3. Contour lines that cross a valley or stream are V shaped. The V points toward the area of highest elevation. If a stream or river flows through the valley, the V points upstream.
4. Closed circles show the tops of hills, mountains, and depressions. Depressions are marked with short, straight lines inside the circle that point down slope to the depression.
Key vocabulary:
topographic map
elevation
contour line
contour interval
relief
index contour
map scale
map legend
Key concepts:
1. Contour lines never cross. All points along contour line represent one elevation.
2. The spacing of contour lines depends on slope characteristics. Contour lines that are close together show a step slope. Contour lines that are far apart show a gentle slope.
3. Contour lines that cross a valley or stream are V shaped. The V points toward the area of highest elevation. If a stream or river flows through the valley, the V points upstream.
4. Closed circles show the tops of hills, mountains, and depressions. Depressions are marked with short, straight lines inside the circle that point down slope to the depression.
Context for Use
This field exercise is designed for middle school Earth Science classes. An average class of 24-30 students working in cooperative groups of 4-5 students each will complete this outdoor field exercise. The location for this exercise can be on the school campus or at another location that has appropriate relief areas that are easily accessible. Prior instruction is needed in the use of an abney level and stadia rod. Estimation of elevation using eye height measurement may also be used. Approximately three 50- minute class periods may be required to complete this investigation.
Description and Teaching Materials
We will use our school campus as the site for this investigation. The designated location will be the small holding pond on the corner of our campus. After a short review of the elements of a topographic map and the use of the cartography instruments, students will gather in assigned cooperative groups of 4-5 students. Given the lowest elevation, each group will use a stadia rod and an abne level to determine the elevation of a wooden bench along the slope of the holding pond. Each student will then draw a diagram illustrating his or her work. They will also submit a written explanation describing how their group determined the elevation of the wooden bench.
Next, group will use this same technique to mark with a flag at least 10 other points. These marks will be joined with flagging tape or brightly colored string. Students will draw a map of their results showing the elevations discovered for each contour line they have created. The map will include a scale and legend. After students return to the classroom, they will create a graph and plot the outdoor elevations they have measured creating a topographic profile.
To complete this activity, students will use a topographic map of our county and their knowledge of map reading to locate different elevations such as the highest and lowest points in our county, our school elevation, and the elevation of their home, as well as different landforms in our area. We will note the slop of our area from the contour intervals noted on the map. We will make the relationship between the surrounding land formations of the Minnesota River to the contour lines that cross a river forming a V shape on the map. We will discuss how a topographic map represents the Earth's surface particularly in our area.
Materials:
Science journal
Pencil
1 Abney level per group
1 Stadia rod per group
Flag tape or string
10 markers per group
Graph paper
Topographic map of Scott County
Tape measure for each group
This activity is adapted from the TIMESXIII Project.
Next, group will use this same technique to mark with a flag at least 10 other points. These marks will be joined with flagging tape or brightly colored string. Students will draw a map of their results showing the elevations discovered for each contour line they have created. The map will include a scale and legend. After students return to the classroom, they will create a graph and plot the outdoor elevations they have measured creating a topographic profile.
To complete this activity, students will use a topographic map of our county and their knowledge of map reading to locate different elevations such as the highest and lowest points in our county, our school elevation, and the elevation of their home, as well as different landforms in our area. We will note the slop of our area from the contour intervals noted on the map. We will make the relationship between the surrounding land formations of the Minnesota River to the contour lines that cross a river forming a V shape on the map. We will discuss how a topographic map represents the Earth's surface particularly in our area.
Materials:
Science journal
Pencil
1 Abney level per group
1 Stadia rod per group
Flag tape or string
10 markers per group
Graph paper
Topographic map of Scott County
Tape measure for each group
This activity is adapted from the TIMESXIII Project.
Teaching Notes and Tips
For safety, students will need to wear long pants and appropriate footwear as the slope they will be working on is covered with vegetation. Stadia rods and abney levels are cartography tools that are not always available. Students could use estimation of contour intervals by using the eye height of two similar students for the elevation measurement and a tape measure for the horizontal measurement.
Assessment
Assessing student knowledge will be through accurate drawings, graphs and writing explanations of student procedure.
Standards
8.1.3.4.1 Create topographic maps and interpret local maps
8.1.3.4.2 Use tools, measurements, graphs and mathematical analysis
8.1.3.4.2 Use tools, measurements, graphs and mathematical analysis