Just so everyone's clear, there is no law of physics that states that the surface of water must be flat. However, fluids with unbalanced forces acting on them will tend to form a surface that is perpendicular to the direction of the combined forces acting on them. On a round earth, the combined forces acting on a fluid, mainly gravity, have a different direction at every point on the earth. This results in bodies of water with surfaces that are curved.
Name me some?
Only naive people would believe water curves. There's a reason why things are called LEVEL. And water LEVEL is not a water CURVE or HUMP.
You people need to start smartening up and taking the morning bus back into reality. You've had your star trek fantasies and what not, so remember them as fantasies and concentrate on seeing your world in a more realistic form, which means, you really need to stop with this water curve nonsense.
Name you some of what?
Also, I've explained this before. The word "level" means different things in different contexts. You can't take the meaning of the word in one context and apply it in another context and expect it to work. The word "level" in this context, as I've said several times before, means perpendicular to the direction of the combined forces acting on the fluid. On a round earth, a surface of water with a non-zero area is not going to be straight. There is absolutely nothing in physics that makes it impossible for the surface of water to be curved.
You could curve water yourself if you like. You can ride the vomit-comet aircraft to experience weightlessness, and if you squirt some water out of a bottle, the water will stick together in a ball. This is because it is energetically favorable for a body of water to take the shape of least surface area, which is a sphere. That's the same reason that water droplets are roughly spherical.
I agree that the idea of curved water is a little hard to wrap your head around at first, but it makes perfect sense when you understand the physics behind it.
They spin and the centripetal force combined with gravity means that the net force is at an angle, so therefore the surface of the water is at an angle.
I would avoid bringing up whirlpools in a conversation with a flat-earther, mikeman. They're going to think you're referring to the Coriolis effect, probably because they don't read posts before responding to them