Since our initial readings of explorers like Christopher Columbus who sailed the ocean blue in 1492, we’ve been reading lots of books about sailors.
Our recent literature and history books have been interspersed by sailors who sight the stars for navigation.
Whether exploring new lands, or Europe’s trade with Asia and Africa, or while colonists ventured across the vast sea to live in another land, the sextant was essential for navigation.
I Found Directions to make a Homemade Sextant
Finding a great resource, I downloaded this document to print out a copy for my son.
How Tall is our House?
Then simplifying the goal, I posed the question to my son: How tall is our two-story house?
Mainly I was curious.
Aiming for the stars yields massive numbers we can’t even begin to fathom.
Measuring the tops of our trees and the top of our house seemed a practical way to start, before aiming for Polaris.
Practicing with the Sextant
On Monday, my son read through and made his sextant.
Then he practiced with a height he could measure, our tall bookcase in the schoolroom.
He made a few mistakes at first.
Undaunted, the gears of his brain whirled while he adjusted his calculations to correctly assess the height while applying all of the math skills he’s been learning.
Geometry Comes in Handy
He’s currently studying geometry in his 6th grade math book where he has recently learned the word tangent. How handy is that?
Finally he figured out where his mistakes were. He was ready to tackle the house!
Siting the Chimney
My son used his straw-taped protractor (aka sextant) to site the chimney.
Meanwhile I stood at his side, reading the protractor for him, telling him when the plumb line measured 45 degrees.
He couldn’t keep the chimney in sight, so he decided to measure to the top of the eaves.
He walked toward the house, sighting with his sextant, until I told him that I saw the plumb line reach 45 degrees.
At that point he stopped and we got the measuring tape out.
I walked the end of the measuring tape to the edge of the house, while he held onto the bulk of it, measuring the distance from the house to where he stood.
That was between 16-17′.
Then he computed his calculations. Apparently the eaves are 21’5″ from the ground.
Extension Questions
Next questions: What’s our latitude? Can he sight Polaris tonight?
This is a great science activity to do with any historical era where the student is learning about sailors who used sextants! Even in the modern era, when fancy equipment fails, navigators resort to this technique!
