Earth! Not! Flat!



I got into a debate with a flat-earther the other day.  After a while I grew to respect the position.  After all, not taking anything on trust is a cornerstone of science.  I pointed out that I've verified the Round Earth theory personally, by creating a sundial that tells both the time and the date.  My sundial was created using a mathematical model that assumes Earth is spherical, spinning about it's axis, and orbiting the sun.  And I've tested it works.  (I also had a job writing code for transceivers that talk to satellites, so you could say I'm a fully signed up round-earther!)

Unfortunately my argument did not convince because it required either
  1. That the flat-earther trusted me, or
  2. That he was willing and able to follow the maths behind the model
This led to to wonder what's the simplest way to demonstrate the Earth is round?  It has to involve no maths, and be easy to reproduce by skeptics anywhere.  The video is my answer to that question.

PS: My first ever vlog!  Does it show?

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