This video has a lot of wasted time, but it's the Eratosthenese experiment done with people from all over the earth, showing the Sun is farther away than just a few thousand km.
I am considering trying to do this experiment or another with people on this site.
The last few days of responses here suggests that flat earth belief is not really about evidence. Sure we discuss evidence because it's fun, but I don't get the sense it matters much.
I think it has more to do with distrust of "science", much of which is justified. In a sense "science" tells us "this is how reality works", which can be imposing, take away one's voice, marginalize, disenfranchize, and isolate. Thus the tendency to group together with like-minded people, to feel less isolated.
That much I understand.
So what do you think. Would doing some experiments yourself help give you some trust in the process?