Simple version for eclipse - the moon will be precisely between the sun and earth, blocking the sunlight and causing darkness. This is the simple answer. What is the simple answer to your model Scepti?
Also, we're not quite finished discussing the 3 mil plastic sheeting spread over your head, and it not squeezing all around your body as if you were in water. You say the pressure is equalized, but the plastic is blocking the miles and miles of stacked atmosphere above you. If what you say is true, that the air acts like water and we have to push our way through the air, as if you were in water, then the plastic would be stuck to your body all the way around. The small amount of air inside the plastic between you and the plastic is NOT holding you to the ground. Nor is the air on top of the plastic. In fact, the plastic doesn't even take the shape of what's it's stretched over.
You cannot say the air pressure is equalized because then you are admitting that it is not the air holding us down. Air pressure squeezes in all directions equally, not DOWN. If air pressure cannot squeeze down a 3 mil thickness of plastic (that's .003 of an inch - 3 thousandths) and confirm around anything, then I'm afraid denspressure has failed.
Now, if you'll take note, I don't spend half my post telling you how brainwashed you are, how indoctrinated you are, gravity blah blah blah, how you just believe due to peer pressure, all of that nonsense, so I'd appreciate it if you would do that to me. All that does is waste time. And skirts the topic at hand. Now I'm serious, I'd really like to discuss this with you. Do the experiment for yourself, you'll see. That pressure holding you down can't even hold down thin plastic.
And, Happy New Year..