There are many ways to prove spherical earth. Let me say an example: Take a look at a ship going out. If the earth is flat, you will notice that the small ship gradually disappears and disappears. Listen to it seems reasonable, but take a closer look. When watching a ship sailing, the ship will disappear from view, but first, you will see the hull of the ship disappear first, then gradually to the sad column, and finally the turn. lost completely. From this it can be said that the Earth must be "curved" a little, this phenomenon can happen. Right?
No not at all, not even a little bit. The surface of a large body of water is flat and level over any distance. Objects on the surface of the ocean are obscured by perspective (bottom up), mirages (bottom up for narrow band), atmospheric magnification (bottom up), atmospheric opacity (entire object) and angular size convergence (entire object). Other atmospheric effects such as diffraction, diffusion and compression that also cause image distortion are also present.
In the case of a boat the bottom part is obscured by a reflection of the area just above it. As the boat gets farther away it gets smaller and a complex form of superior mirage that's seen in a narrow band along the horizon called a Fata Morgana which remains the same size, covers more and more of it. Eventually the angular size of the boat is so small the entire vessel is engulfed by the mirage and disappears. Other effects such as perspective, magnification and compression can also be present depending on the situation.
The fact objects are never seen to lean backwards shows they're not traveling down hill. The idea that ships go up, over and behind a giant hump of water three miles out is plainly ridiculous. There's no argument for curved water and all experiments ever conducted show that water forms a level surface. Even more obvious is the horizon rising to eye level at any altitude, you'd be looking down at it if the ocean were curved.