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Sextants (Wikipedia) and earlier navigational tools - they could double as surveying instruments. Main point: instruments Then had many parts and observations were tedious but still more accurate than our everyday measurements Now (degree of latitude mid-19th-C: withing 1/2 mile); instruments now are electronic and gather far more data with far greater accuracy - and we don't have to do much math. Turning point for the sextant: sometime after 1945; AvH would have understood the 1945 sextant - it was mechanically much like the sextants of his time; but the iPhone "Sextant" app would puzzle him (for a while), because it's not mechanical. He would, however, understand the workings of GPS. 1) Hands-on primitive version (while talking like pirates, but with Franciscan prayers and rowers "singing soft, sad songs" in background); 16th-century equivalent: the backstaff (but not as primitive as our combination of trianble & carpenter's level) 2) Modern update of traditional instrument in use on relatively calm seas; explanation of use; 3) Closer look at the standard sextant of the 18th Century: the sextant Captain Cook used; 4) What Humboldt used: the (slightly high-end) tools of the time, but with the skills expected from every ship's captain and officers 5) A WWII-era sextant: its developer and basic principles; 6) Celestial navigation with instruments developed by various cultures (Polynesians, Arabs) 7) "How does X work?" - the difference between "how do you make it work" and "how it works"; example: how GPS works; more about GPS; step-by-step GPS tutorial; Free iPhone apps related to navigation demonstrations: "Skytime", "AstroCLock", "Thedolite", "Elevation", "Trig Solver" (actually does just triangles, but that's what we want), and maybe (advanced users:) "Spyglass". The same or similar apps exist for Android. Upcoming math challenge: how accurate is the "Theodolite" app? But first: How long is 1/10,000 of a degree of latitude? in feet? in meters? |