I have already posted this elsewhere, but I think this might be a more appropriate place for it.
From what I hear, you people explain time zones by the sun being a spotlight, but if that's the case then why does the sun rise and set? If the sun was a spotlight shining in a certain direction and moving it's light in circles, then wouldn't it appear to hover in more or less the same position in the sky? Any citizen of Earth would know that the sun in fact rises and sets in the course of a day, but if it actually did go below the horizon in a flat Earth then why can I still see it here in the US after my friends in the UK tell me that it set?
If you still think that the Earth is flat, try going to a beach and trying to see the coast of another continent, which would be possible in a flat Earth. You would notice that you just see what can either be an infinite ocean (which we all know is not the case) or the ocean curving away from you. You can also try looking at clouds and how they seem to curve down to meet the horizon as they get further.
If you didn't know this already, there is a program called Google Earth (Found here:
https://www.google.com/earth/) that shows the entire Earth as seen from satellites, it's so accurate that I can see the exact location of trees and bushes in the back yard of my house, you should check it out.
I have witnesses lunar eclipses that were low in the horizon, and yet still the shadow of the Earth was as round as ever, which shouldn't happen if the Earth was flat.
The sun always appears in approximately the same place relative to the stars no matter where on Earth you look at it from.
You know when you
Look up into the night sky and look for tiny dim dots that do not flash cruising across the sky. Those are satellites that orbit the Earth.
The round Earth heliocentric model can predict the location of planets with 100% accuracy, and I should know because I use that model to find planets when I bring my telescope out to look at them.
The strength of gravity is not the same everywhere on Earth.
Hurricanes are impossible if the Earth doesn't rotate.
Antarctica is not shaped like a doughnut
The sun is below the horizon for about 6 months in the north and south poles, yet it's high in the sky over here while that's happening.
There are stars that are visible in the southern hemisphere that are not viable in the north hemisphere, and visa versa.
Another good proof that the Earth is round is the seasons. Your explanation for the seasons is that the sun goes in circles around the north pole, but if that was the case then what season it is based on the time of year would be dependent on your latitude and all 4 seasons would be present somewhere at any given time. How it actually works is that your latitude doesn't matter and seasons on the northern and southern hemispheres are opposite, when one is summer the other is winter and when one is spring the other is fall. This is not explained by your model.
In the flat Earth model, the continents are not the right shape.
I could go on, but I think this is enough.