You can read more about why I believe in a Flat earth in my AMA thread in the Q&A forum.
But to answer your question, the Flat Earth is not easily disproven otherwise the debate would have ended.
Even Wikipedia admits that the Heliocentric model and Geocentric model BOTH work:
The motions of the sun, moon and other solar system planets can be calculated using a geocentric model (the earth is at the centre) or using a heliocentric model (the sun is at the centre). Both work..
Source:
https://en.wikipedia.org/wiki/Occam%27s_razorNow it goes on to say that Geocentric model has more assumptions so according to Occam's Razor the Heliocentric model should be correct.
However, that is just not true.
To believe in the Heliocentric model, you have to assume that an invisible, non-measurable force (Gravity) holds everything in place while simultaneously allowing the universe to expand.
You have to assume that your eyes are deceiving you to see the earth is flat when it is really round. You have to assume that mirages are deceiving you into seeing buildings much farther than you should.
You have to assume that humans (which are inherently evil) are telling the truth about traveling in space. You have to assume that although no independent rocket or balloon can go higher than 30 miles, NASA was able to go 220,000+ miles in the 1960s using a calculator.
You have to assume that although the Sun and Moon appear the same exact size, the Sun is 400x bigger and ironically 400x farther away.