I'll redo this and be a bit more explicit.
If you accept the Globe you accept gravitation. End of story!
The video starts out boldly proclaiming:
Water ALWAYS Maintains a LEVEL
Water does NOT bend or curve
That is simply not, nor has it ever been a law, no more than the saying
"Water seeks its own level", but that does NOT say that the surface of water is always level, or straight.
There are numerous cases where, because of non-vertical forces being applied to water that the surface is not "straight".
A trivial case is a dew-drop. It is certainly not flat, why? Simply because there are forces other that gravity acting on it. In this case the force is "Surface Tension". | | |
There are other forces that can be applied, for example, we could rotate tank of water smoothly, as in this video
Of course, you will say that the water in that tank is not only subject to the downward acceleration of gravity (or whatever you choose to call it), but to an additional acceleration due its rotation.
EXACTLY! The nett acceleration is not in a single direction anymore and the surface aligns itself at right angles to this nett acceleration at each location, as illustrated below:
Rotating Water Curving Now, please understand that the only reason I am showing this it simply to demonstrate that the surface of water need not be "straight". It simply depends on the local acceleration, here gravity (down) and centrifugal acceleration (outwards). So at the outside edge, the surface of the water is at about 45° to the horizontal.
I am not suggesting that the rotation of the earth holds the oceans in place, it most certainly does not.
There are other examples such as in eddies and whirlpools, where again an acceleration due to rotation is involved.
On the Globe the gravitational acceleration is always directed towards the centre of the earth as in:
Water Curves on GlobeExcuse my poor image of the globe.
So the nett force is not towards the centre of the globe, so the water tries to go "down" as far as possible and follows the curve of the earth.
So while it may be true that
"Water seeks its own level", that level need not be straight or flat.