If there's absolute proof that the earth is round, why tell them something that just isn't true? That's like me knowing 100% that mt keyboard is black. I know it through and through, and there's infallible proof- but then saying "Well, so and so thinks it's pink, so you choose". I suppose you COULD, but that would be giving them misinformation.

I have not heard of this theory,or is it from the middle ages.How can one make a round earth flat?Sound like complete nonsense to me.We don't need more confusion in this world.

No, because it is not mainstream science. In fact, very few scientists support today this theory. It was not always so in the past. But we could tell in schools that many people in the past thought that the earth was flat. Further information about the flat earth theory here: http://en.wikipedia.org/wiki/Flat_earth Another alternative theory, which should also not be taught in schools as a real alternative, but just as some very controversial (if not crazy) idea, is that of the hollow earth. "Instead of saying that humans live on the outside surface of a hollow planet, sometimes called a "convex" hollow-Earth theory, some have claimed that our universe itself lies in the interior of a hollow world, calling this a "concave" hollow-Earth theory. The surface of the Earth, according to such a view, might resemble the interior shell of a Dyson sphere. Generally, scientists have taken neither type of speculation seriously." "Stories have even been circulated, although apparently without historical documentation, that Hitler was influenced by concave hollow-Earth ideas and sent an expedition in an unsuccessful attempt to spy on the British fleet by aiming cameras up into the sky" Source: http://en.wikipedia.org/wiki/Hollow_earth

I hope you are joking because I can't imagine anyone thinking that the earth is flat!!! LOL where did you go to school?

NO.

It should only be taught in schools that teach creationism.