We know by observation that lighter things float and heavier things fall or sink.
Okay, we have some common ground, we both observe the same thing. However when posed with a direct question to explain your world view's driving mechanism for the "fall" vector, you instead explain what you observe and do not offer further explanation. I, on the other hand, say that gravity in conjunction with differential density is what causes the stratification and the bolt to "fall".
You may have missed my post earlier.
Post 273
Can you through logic or mathematics explain why accelerometers react the way they do to acceleration and as you would put it "density". I say gravity.
Gravity is not a constant. The variations are consistent and mathematically supportable in a way that density would fall apart. Gravity varies with:
latitude - the Earth's equatorial bulge means that surface gravity is lessened as you mover further from the equator.
Centripetal force - counteracts gravity differently for differing place on Earth at differing radius from the center.
Elevation - the higher the elevation, the farther from the Earth's center, the lower is gravity.
Local anomalies - due to the mass density variation of landforms. Rock vs. ocean, etc.
When I ship an instrument from Connecticut to Kennedy Space Center. I have to make corrections in the gravity factor in order for the instrument to pass its self diagnostics tests. These instruments happen to be center of gravity instruments. My occupation, my company, my customers, are not frauds. If what I did for a living was a fraud, if gravity were a fraud, many of our country's most sophisticated weapon systems would simply not work. They do work. See Ukraine. Hundreds of thousands of people around the world would have to be "in" on the scam. Puck-ass college students would have figured it out years ago and the gig would be up.