so, how do you know for sure it's a sphere?

I don’t know for sure it’s a sphere. Most things in science are called theories, as nothing is certain.
Science was and has always been constructed around theories. Nothing is certain. However that doesn’t mean just cause some things are not certain, others are. In other words one being incorrect doesn’t mean another incorrect idea is correct. But look at examples of scientific development, from Dalston to Thomson and Schrödinger/Heisenberg's atomic models, Newton to Einstein's laws of physics, etc. When the theories were proved inaccurate, science refines them.

I have never seen it with my own eyes, but the experiments done and the math says it is round.

A lot of people around here would call that an "appeal to authority." That is to say that people have told you it is a globe and you're willing to believe them. In a debate setting, that's not exactly convincing evidence.

The flat earth theory seems to be built around this idea that “if I didn’t see it then it’s not true” or that it doesn’t exist. Which is ridiculous. Atoms exist, but you don’t see them.
Most flat earthers I have talked to tend to bring up the Bible, but if they have never seen god or talked to him..would u call that an “appeal to authority.”

I can use math

To prove it

Well there is so single equation of course

It’s a mix of experiments done to come to a conclusion

An appeal to faith is not something I would consider during a debate either. A lot of flat earthers around here will be happy to provide you with a lot of evidence and experiments.

Evidence?

What evidence

Also what experiments

Well, I actually just had a talk earlier today with another staff member about the Black Swan evidence.

I'll pull it up, just a sec

https://i.pinimg.com/originals/af/58/63/af5863c957acd702af83399ad0694514.jpg

The argument is that the visible horizon behind the second rig shouldn't be visible.

Due to the maximum distance with refraction one should be able to see on a globe.

well the GEOMETRIC HORIZON should be NO fartther, and all from, one foot should be 1.22miles

we see ten miles plus

^ Lograin's an expert on this

not expert, but this is basic geometry

the physical line horizon, geometric horizon, is what glob erfers claim ships disappear over, so this isnt a REFRACTED horizon

You still with us, Siegfried?

this is the issues, so now we can see ten miles at one foot OH proves that R of glob model is wrong

an to match our observations R would have to be 230,000miles

I have no idea wtf he’s talking about

So you dont geometry

okay

we can see farther than we're supposed to

“well the GEOMETRIC HORIZON should be NO fartther, and all from, one foot should be 1.22miles” what?...

you glob model asserts a PHYSICAL horizon

What do u mean we can see farther

called a GEOMETRIC HORIZON

this is the PHYSICAL: line you asssert ships dissappear over

BUT we do not OBSERVE this

when you calculate the GH from OH of one foot its 1.22 miles

and its impossible to see farther

as there is a PHYSIACAL obstruction

either the 'curve' water or land