Little physics problem

[Vtile]

Fluids: air and water. Water is liquid so its delta volume vs pressure is a lot smaller than what the pressure vs gas are. When we go up the pressure will drop. If the object is rigid aka not airballoon then its volume weight of air (and also mass because of std g is ~9.815 only at sealevel, but the effect is the same to all objects in this) is more than in sealevel. It will probably float in water slighty less.

..without calculations or analysis at the middle of the night.