Okay then I don't understand the point of your "standing on a sphere" comment.
Okay, so let's assume that we place this container midpoint first and while it rests perfectly balanced (for the sake of the thought exercise, let's assume glass doesn't break, heh), we fill in the space between its underside and the ground with dirt (or whatever) such that the container never moves until we're done. Then we fill it with water and let it rest. Would the water take any particular shape?
Great question, and actually it has me rethinking what I wrote earlier.
Short answer: the surface of the water will be flat, as the top of the container.
Disclaimer: I understand you are doubting the shape of the earth, but since you asked relative to the current working theory of a globe earth, I am going to make statements about that only due to the fact that it's relevant to the specific question. Anyway:
Gravity is a downward force, but it might be easier to say that it's an inward force, originating from the center of Earth's mass. When it comes down to it, gravity is pulling everything in to a singlular point at Earth's core, which gets weaker as we get further away. This is one important element to the equation
Fluids, like water, will always take the shape of the container they're in, in this case a rectangle. They will also obey the laws of gravity (obvi) pulling it towards the earth.
In the case of what you wrote here, the water will not curve, and that is due to the shape of the container that it's in, which is flat. Gravity is still pulling the water downward, but since the container is so long technically there is an ever so slightly weaker gravitational force on the ends of the container vs the middle, but it's negligible. The fluid will still keep the shape of its container.
So, I apologize for the comment above:
Assuming the container is flat along the top and bottom, the water wouldn't be parallel with the rim of the glass.
Okay then I don't understand the point of your "standing on a sphere" comment.
Great question, and actually it has me rethinking what I wrote earlier.
Short answer: the surface of the water will be flat, as the top of the container.
Disclaimer: I understand you are doubting the shape of the earth, but since you asked relative to the current working theory of a globe earth, I am going to make statements about that only due to the fact that it's relevant to the specific question. Anyway:
Gravity is a downward force, but it might be easier to say that it's an inward force, originating from the center of Earth's mass. When it comes down to it, gravity is pulling everything in to a singlular point at Earth's core, which gets weaker as we get further away. This is one important element to the equation
Fluids, like water, will always take the shape of the container they're in, in this case a rectangle. They will also obey the laws of gravity (obvi) pulling it towards the earth.
In the case of what you wrote here, the water will not curve, and that is due to the shape of the container that it's in, which is flat. Gravity is still pulling the water downward, but since the container is so long technically there is an ever so slightly weaker gravitational force on the ends of the container vs the middle, but it's negligible. The fluid will still keep the shape of its container.
So, I apologize for the comment above:
Because it is completely wrong