Sinking & Floating

Sinking or Floating: 
How something as common as water disproves the Gravity Conspiracy Theory

So if there is no such thing as gravity, why do items with more mass sink while items with less mass float? 

The answer is actually a combination of a couple of things. It has to do with centripetal forces and molecular spacing of matter. Basically it is the reverse of how a centrifuge works, which uses centrifugal force, or force directed out from the center of a rotating body, pushes the more dense materials out. But the prevailing force for the earth is centripetal force, or force pulling towards the center of a rotating body. 

This force, instead of pushing more dense materials (or those materials with less space between its composite molecules) outwards, it pulls the denser materials in, causing “heavier” objects to sink and “lighter” objects to float. 

For instance, think of an ice cube floating in a glass of water. The water has achieved the state where the molecules are as close together as they can possibly get (uncompressible). Now ice, despite being a solid, has molecules farther apart than its liquid form (which is why ice expands). So the centripetal force of the earth pulls the water towards its center, and the more closely packed water molecules push the more loosely packed ice molecules out, causing the ice to “float”.