To disprove that earth is a flat disc, all the continents being on one plane, the only thing hindering our adility to see them being haze, we should simply take one of the many powerful telescopes we (by we, I mean round-earth believers, since those other guys don't think we can make such instruments..), align it horizontally, and try to look at China. I don't think haze should be a problem...since we can already look at the moon and other planets down here on earth!
Ok, obviously the point of this point is to say that if we tried that, we would fail miserably, because earth is round.
Once again, by "we," I mean round-earth believers because flat-earth believers still use fire for light.