Lab Manual: Making of a Clinometer | Lab Manuals for Class 10 PDF Download

Objective

• Concept of angle of elevation and depression.
• Properties of right-angled triangle.

Materials Required
Small pipe or drinking straw, a wooden board, wooden strip, thread, weight, screw, geometry box, etc.

Procedure

• Prepare a semi-circular protractor with the help of geometry box. Mark degrees in sexagesimal scale with 0° at the lowest and 10 to 90° proceeding both clockwise and anti-clockwise.
• Fix a hollow pipe along the diameter of it fig. (i).
• Punch a whole at the centre of a semicircle.
• Suspend a weight (w) from a small nail fixed to the centre.
• Ensure that the weight at the end of the string hangs below the protractor.
  

Determining the Height of an Object:

• Measure the distance of the object from you. Let it is d.
• Look through the hollow pipe straw at the top of the object by rotating it gradually. Make sure that you can clearly see the top of the object.
• Hold the clinometer steady and record the angle which the string makes on the scale of the clinometer. This angle is the required angle of elevation , let be θ .
  Using trigonometric ratio:
  tan θ = height / distance = h/d
  h=d.tan θ

Observation

• angle of elevation 0.
• distance between object and clinometer d.
• height of clinometer/(let)
  Therefore height of object = l  +  h = l + dtanθ
  

Result
Angle of elevation can be found easily.

Learning Outcome
Students learn how to determine the angle of elevation of an object by clinometer and use of it to determine the height of an object at a known distance.

Activity Time

• If the height of clinometer is 3 m, distance between object and clinometer is 27 m and angle of elevation is 45°. What is the height of an object?
• A kite is flying at a height of 40√3 metre from the ground level, attached to a string inclined at 60° to the horizontal. What is the length of the string?