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How to Make a Clinometer With a Straw Using Trigonometry

A clinometer is an instrument for measuring angles in the vertical plane, and is a useful tool for determining the height of an object that cannot be directly measured. The rules of trigonometry enable the height of an object to be calculated once the distance to the base of an object, and the angle to its top are known. A simple clinometer can be created from a drinking straw and a protractor.

Things You'll Need

Drinking straw
Protractor
Thin thread
Sticking tape
Bradawl or hole punch
Glue
Small weight ( such as a steel nut or a blob of modeling clay)

Instructions

- 1
  Tape a drinking straw to the straight edge of a protractor to create a sight though which you can aim the clinometer. Position the straw so that it overhangs both ends of the protractor by about an inch.
- 2
  Make a hole in the protractor where the 90-degree line meets the baseline, halfway across the width of the protractor. Tie a knot in one end of a length of thread and pass it through the hole. Add a drop of glue to secure the knot to the protractor.
- 3
  Hold the clinometer with the straw on top and the protractor hanging down vertically below it. Cut the thread so it hangs about four inches lower than the bottom edge of the protractor.
- 4
  Attach a small weight to the lower end of the thread to create a plumb line. Hold the clinometer with the straw horizontal to the ground. Observe the plumb line; it should hang vertically along the 90-degree line. Tilt the clinometer, and the plumb line indicates the angle of tilt.

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