Here’s how this went down. People believe the Earth is flat. No kidding. All over YouTube and social media giant Quora.com. (There’s an app for that.)
On Quora I used an example of driving a car across the Lake Pontchartrain causeway to rebuke the idea which I also reposted here on my blog.

They’ve come up with a rebuttal on YouTube. I watched the video, then made this response to whoever made it:
[youtube https://www.youtube.com/watch?v=zoVK4XPe9zc]My response:

I’ve driven across this bridge on Lake Pontchartrain. I’m a scientifically minded non-scientist. I believe the world is round, but I’m not going to write you off. I want to understand. In the middle of Lake Pontchartrain, for 8 miles at the altitude above the water and your car, the horizon to the north disappears and you see nothing but water in all directions. Then as you continue south, using binoculars, you can actually see downtown New Orleans rise from the sea. How do you explain this? I’m not being judgmental. I really want to understand your viewpoint. That being said, there is a serious flaw to your logic and I think it’s because you don’t understand basic math. Over the 24 miles of the bridge, the Earth drops down 270 feet. You seem to assume then that you need to come up with 270 feet of roadway. Well, maybe if you just wanted to suddenly have a vertical cliff of 270 feet somewhere in the road. By adding only a few inches to the roadway to keep it conforming to the curvature, at the end the bridge meets up. Let me see if I can’t give you an example from my personal experience as a non-commercial pilot. Once I calculated that to fly from Bellingham, Washington to Olympia for my first cross country flight, I needed to go in a certain direction, given windspeed and all. I was a few degrees off in my calculation. Very very small. When I got to the other side I was many many miles away from where I needed to be. The same thing with Lake Pontchartrain. You’re intelligent. You must know this. It only takes a few inches to correct a problem that otherwise down the road would be 270 feet.