Comments by "Laurence Fraser" (@laurencefraser) on "Response to Globebusters - The Earth Still Isn't Flat" video.

@bharadwajv79 a decent sand dune on a beach, or a cliff facing out to sea is enough to be able to see the horizon curve. Build a frame at the top, aligned with the sea as perfectly as you can manage. Use a spirit level to ensure a crossbar (preferably a couple of metres long), the centre of which is also aligned to the horizon, is perfectly level. Then compare it to the horizon at different points along its length. They don't match. Either the horizon curves... Or your spirit level does. A ship (large sailing ships make it particularly obvious) sailing away from you demonstrates the curve in that direction as, rather than getting so small as to be invisible (as would be the case if they were traveling away in a straight line) the Bottom of them disappears first.
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