How to Use an Inclinometer to Measure Height
Or building? Or rocket?
In this article, you will learn how to use an inclinometer to measure height with the help of a little trigonometry and a calculator.
We need to be able to measure the angle between us and the thing we are measuring the height of as seen in the diagram to the right.
It is super easy to use an inclinometer to measure height, as you will see. There are a million protractors you can print out from the internet but to save you time looking, here’s one you can use. Print this out and glue it to a piece of cardboard or thin veneer.
Tape a straw or a paper cylinder to the top so you have something to look through. It should look something like the picture to the right. Poke a hole where it looks like you need a hole loop a string through the hole and hang a weight from it. When you look at the top of something through the cylinder, the weight will hang vertically and tell you the angle of elevation.
Now, you can’t see it because you are looking through the hole, not at the angle so you can either:
1) Get a friend to tell you the angle or:
2) Squeeze the string against the cardboard with your fingers, stop looking at the object and look at the angle.
You need one more thing before you can do the calculation; the distance to the bottom of “the thing” you are looking at. Measure that distance accurately with a tape measure or guestimate the distance by pacing it off.
The only formula you need to know is the following:
Height = distance X tan x, where x is the angle you measured.
Any cheap calculator will have a tangent (tan) key on it. Or you can easily find one online. Or you can download one for free at http://www.esbconsult.com/esbcalc/esbcalc.htm . They have a version for your computer as well as one that you can put on a USB flash drive.
The distance to the tree is 10 meters and the angle of elevation is 65 degrees. The height of the tree is:
Height = 10 x tan 65 = 21.45 meters
Of course, you can add your height to the measurement since, in theory, you are measuring from your eyeball but hopefully you are not looking for that kind of accuracy using this type of equipment! Using this technique, you can use an inclinometer to measure the height of any object.