OK so water, if you look at in a glass, is concave relative to the edge of the glass, this should be done on the salt flats. Perspective is a key understanding. The action of taking the derivative through observation is fallible. Remember also that the measurement must include lift and sink in the footprint where the experiment is done. The topographical aspect of this experiment is key. Remember though, that these idiots are using "stupid" science for people that can not add or subtract without using their fingers.

It was your title that triggered me. I am on a mission to throw these people under the bus that advocate the nonsense of a flat earth. You are right though had I watched this, I would have had a different perspective.