Page #69
Page #69
About this Page: I really love this page. A big thank you to Dan Harris for my Eratosthenes, Ricci, and Blaeu. I really can’t do this without him. I told him that I wanted a Ricci and Blaeu in a selfie “bro” pose, and he did it! I was able to illustrate the back of the camera as well as Eratosthenes’ Earth and the gnomon. The background, text, and name titles are done by myself. I hope to create a grouping of geography philosopher stickers one day for people wanting to get them. I think so far, I could have around 8-10, with more to go from further chapters. Anyway. Did you ever hear the story of the guy who was able to measure the circumference of the Earth without modern calculators or satellites
within 200 miles of accuracy? Yeah, me too. Enter, Eratosthenes. I always told my students about his contributions to geography and history, but I never told him how he did it. I figured it was trigonometry that was wayyyyy over my head. But, it’s not. The background script next to Eratosthenes’ head explains it briefly, but you can check out one of these great sites that helped me to better understand it. 1 (with slideshow) ; 2 (Business Insider w/video) ; 3 (A Lesson plan for second graders apparently, but good enough for my sophomores). Moving on, I don’t know if Matteo Ricci and Willem Blaeu knew each other, but they were contemporaries, which is pretty cool. One hung out in China for most of the time, so I imagined them using Instagram to keep in touch. Here is the rough sketch of Eratosthenes that I gave Dan to work with. 
The biggest challenge was getting the Google Earth image of Earth at the right angle to show Alexandria and the gnomon, in relation to Eratosthenes’ body. Once I finagled the angle, a good old screenshot helped me with my Earth sketch. 
On that note, have a good rest of the day, and happy contemplating the contributions of Trigonometry to the world.
