Introduction to Topographic Maps

 

Allison Kao

Community Roots Charter School, Brooklyn

Summer Research Program for Science Teachers

August 2010

 

 

Subject:  Earth Science

Grade Level: 10th

Unit: Landforms and Topographic Maps

Duration:  1 period (~45 minutes)

Aim:  How can we use a model mountain to understand and generate a topographic map?

Objectives: SWBAT

-           

Vocabulary: Topography, topographic map, isolines, contour lines, gradient, field value, elevation, distance, field value

Materials:

- modeling clay (enough for either each student or pairs of students)

- floss or fishing line or thin wire

- graph paper or white paper

- colored pencils

- class notes

- homework/worksheet

 

Lesson:

-     In your own words, how would you describe what a slope is?

-          How would you go about calculating the slope of a mountain (hint: think about math)?

Discuss à turn and talk to someone next to you and share answers. Randomly call on a few pairs of students and write their answers on the board.

Clay Activity and Class Notes (25 minutes) – while going through the mini-lesson

lecture and allowing students to write their notes and see examples/images, insert the model mountain activity’s procedures in places where appropriate.

                        Mini- Lesson:

Field Maps

n    An area that has some kind of measure at every point

n    Isolines or Contour Lines connect points of the same value

n    Gradients tell the rate of change: the closer the lines, the bigger the slope

Gradient

n    Gradient = change in field value / distance

n    Field value: a measurement at a point (temperature or elevation)

n    Distance: length between 2 points

Topographic Map

n    Shows elevation of the earth’s surface

à HERE you can begin the model mountain activity (see below for procedure)

n    Contour lines tell elevation differences between lines.

n    Contour lines NEVER touch or intersect.

Reading a Topographic Map

n    A bird’s eye view.

n    Look at the scale. The scale will help you to calculate gradient.

n    Thick lines show elevations. (You can count the lines in between to find the elevation of EACH line.)

n    Look for the highest points: concentric circles get smaller and smaller.

On your map:

n      Draw and arrow and label where the top of the mountain is located.

n      Draw and arrow and label where the base of the mountain is located.

 

Model Mountain Procedure:

  1. Pass out graph paper or white paper, piece of clay, 3 colored pencils, piece of floss/fishing string/wire
  2. Ask students to mold their piece of clay into some kind of basic mountain shape
  3. Using floss/fishing string/wire cut 3 parallel lines that go ACROSS your mountain (should go all the way through from one side of the mountain to the other side). Be sure that the lines you cut are as evenly spaced as you can be. You can use the width of your thumb as a standard.
  4. Separate each piece from one another and place them in a row on your paper. Be sure not to turn any pieces upside down or mold any of them.
  5. In the middle of your paper, place the largest piece of clay cut. Pick one colored pencil and trace around the entire piece of clay. Then carefully remove it and put it back into the row.
  6. Take the next piece and place it INSIDE of where you traced, making sure the edge does not touch the line of where you just traced. Using a different colored pencil, trace around the clay and repeat until all pieces are traced.

 

            Discussion (5 minutes) -- allow students to use their notes as a reference to

answer the following questions. Be sure they use the new vocabulary terms!

n      How did your model mountain become a topographic map?

n      Why do you think we used different colored pencils?

n      Why are some lines closer together than others?

n      How would your map change if you made a really steep mountain?

n      Looking at your map, where would be the best place to make a hiking trail to the top? Why?

 

            Worksheet / Homework (10 minutes)

-       Students begin their worksheet, which is also their homework

-       Go around the room to assess student understanding and clarify any questions

-       May need to provide more colored pencils and rulers

Have students use their clay to model the mountain in worksheet and cut into pieces to compare with paper




New York State Standards: 

Standard 1: Analysis, Inquiry, and Design - Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose questions, seek answers, and develop solutions.

Standard 6: Interconnectedness-Common Themes (Models) Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design