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NCTM Activity - Clinometer 1
Task with Student Directions
GLOBE Assessment
Grade 9-12

Math Activity for Protocol Test

Chris has an eye height of 1.65 meters. When Chris stands 62 meters away from the tree, the clinometer records an angle of 24 degrees. What is the height of the tree?

NCTM Standard: geometry 1.4
(tree height = (TAN – BVW) x (distance to object) + eye height
What is the first calculation that you do? multiply or add?

NCTM Standard: algebra 2.3

Clinometer Protocol Test

The Clinometer protocol test assesses students' ability to construct and use a clinometer.

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Construction & Use of Clinometer Protocol Test




Student activity & Level of Performance

+ appropriate student performance

- inappropriate student performance

n.a. not appropriate or not observed


clinometer sheet

table of tangents


drinking straw

metal nut/washer

15 cm of thread/floss

glue, scissors

hole-punch, tape

Construct Clinometer                                              
Attach clinometer to one side and table of tangents to other side of cardboard                                              
Punch hole at marked circle; tie 15 cm. string (attached to metal nut/washer) through hole                                              
Tape straw along designated line to use as a sight                                              
Using the Clinometer                                              
Stand on level ground with object being measured                                              
Measure & record height of eyes from the ground                                              
Sight top of object through clinometer straw                                              
Partner records – BVW (string + washer)                                              
Measure & record distance from observer to object                                              
Calculate & record height of object:

Tree height = (TAN – BVW x distance to object) + eye height




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