The last statement is so true.
Let us assume the magnetic force is the Qi. I think this is how peole may had came up with the following notion: “Qi rides with the wind and is stopped at the boundary of water.”
I think Qi is the magnetic field that surrounds this planet. The mgnetic field has two directions (call it Yin & Yang, Positive ion & Negative ion or anything that has the characteristics with only two elements). The magnetic foerce travels through the air, which the human eyes cannot see.
People at that time probably though there is no way to stop Qi (the magnetic force) in the air, but could some how temporary idle Qi. Earth and water are probably the only two elements that could slow down the Qi, probably because the masses are beyond what the human’s eyes could see or measure (will at least at that time).
Earth does not move on its own. It could be store but not easily be move. Water, however, constatnly moves. Thus, when the ocean or lake waves back and forward, people in those days probably thought Qi is push by the wind then lands into the water. Thus the water moves. When the water moves again, the Qi is been picked up by the wind again (gravity moves water then what affect the planet’s gravity? I was never good in science and will let the rest of the readers to decide).
If the surrounding Qi is properly channel, how could Qi be better use or broken down into the 5 elements, I don’t have any comments (truth is, I don’t know and still learning).
Just my 2 cents.