Thanks for the reply @Jack44556677
Was that not the way you were (initially) taught? How about yourself?
To be honest, I can't actually remember the first example I was taught. Let's take your setting sun/boats/stars example as a start point though. I certainly wouldn't suggest that the apparent disappearance of these things, bottom up, as they reach the horizon is conclusive proof, in isolation, that the earth is round, however it does strongly suggest that something interesting is happening - somehow, boats, the sun and the stars are disappearing from view in a way that we wouldn't expect on a flat earth - and that deserves closer attention/investigation.
No globe proofs withstand much critical scrutiny, which in and of itself is interesting.
I would strongly disagree with that. Can I offer a couple up for your critical attention?
1. taking your setting stars example from above. For me, the position and movement of the stars in the night sky is pretty compelling evidence that we are on a globe, and that the stars are extremely distant. The fact that, for example, I can determine my latitude by simply observing the elevation angle of Polaris (in the northern hemisphere) or Sigma Octantis (in the southern) is entirely consistent with a globe-shaped earth. Moreover, if one takes elevation angle measurements of, for example, Polaris from three or more different locations at the same time, the only way the three lines can intersect at one single position of the star is if the earth is round and the star is distant. If you try this on a flat earth, you end up with the star being in different positions depending on where you view it from. So FET has to explain this away by invoking magical light bending (EA), but this just creates more problems - if light bends vertically the closer a source gets to the horizon, why does the vertical distance between stars not change as they get lower?
There are numerous other star-related problems with FET. Why do the stars disappear below the horizon at all? The FET wiki invokes perspective...but if perspective is at work, why doesn't the azimuth or elevation angle between the stars change as they get lower in the sky? If perspective was a factor, and the stars were becoming more distant, they would appear to get closer and closer together, just as distant objects on the surface of the earth do. But they don't.
2. A very technical, niche example, but an interesting one. In aviation, directional gyroscopes are used to provide stabilised heading information. Directional gyroscopes are often fitted with a 'drift nut', which is an adjustable weight mechanism that provides a correcting force to compensate for the rotation of the earth. This adjustment is made for the latitude of the aircraft, as the rotation effect is maximised at the poles, and zero at the equator. Why would instruments designers implement a mechanism that would make the instrument less accurate if the earth was flat?
Interested in your thoughts.