Exploring the McKenzie

 

Watershed

 

 

 

 

 
Idea Bank
Before going on a field trip, have students craft a simple clinometer and learn how to use it to estimate the height of trees.

 

Make a clinometer using:

  • a square piece of paper or card stock,
  • a drinking straw,
  • a string and
  • a weight (such as a washer or nut).

 

 

A

B

Fold the square of paper or card stock to form a triangle (if the paper was square, the triangle should be a right isosceles triangle-- 2 sides of equal length, a 90 degree angle and two 45 degree angles)

C

Tape the drinking straw along the long edge of the triangle. This will be used as a site.

D

At the upper end of the long fold, attach the string. Tie the weight to the other end of the string, making it long enough so that the weight dangles a few inches below the corner of the triangle, as shown in the diagram. Held as shown in diagram D, a student will look up through the non-string end of the straw to site a tree top.

 

 

  1. To use the simple clinometer, students should work in pairs. One student looks up though the straw to sight the top of the tree, while the other student guides the first student and tells her when the clinometer string is hanging straight down. (The string should be parallel to the edge of the card stock as shown in diagram D.)
  2. When the student sighting through the clinometer is the correct distance from the tree, the students should mark the ground and measure the distance from the mark to the base of the tree. This distance (plus the height from the student's eyes to the ground) should provide a reliable estimate of the height of the tree.
  3. Can you explain why this method works? Hint: this method of measuring tree height is sometimes called the isosceles-right triangle method.

Idea Bank: The Idea Bank links to a resource of study topics and activities appropriate for many sites. For a complete listing of Idea Bank contents, click here.

 

This activity would be especially appropriate for the following sites:

  • Hendricks Bridge Wayside Park
  • Delta Campground
  • Waterboard Park
  • Big Lake
  • Lava Site

 

Related Activities:

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This project is funded by a grant from Eugene Water and Electric Board in partnership with Eugene School District 4J. The McKenzie watershed is a source of drinking water and electric power for the Eugene community. Copyright 1997. Feedback? http://Cyberschool.4j.lane.edu/McKenzie/home.html

 

Eugene School District