If an object is less dense than water, or if it floats on water, it displaces the same weight of water equal to the weight of the object. If the object sinks in water, it displaces a volume of water equal to the volume of the object. This is known as the Archimedes principle
lighter
I'm not exactly sure what you mean when you say "heavier" and "lighter". Does that mean the object's "weight" ? Could that be the same as the gravitational force on it ?
When they're both at the same height, the heavier object has more gravitational potential energy.
Yes because according to newton 1st law
if the water is heavier than the item inside it, then the water sinks to underneath the object. if the object is heavier then the object will sink under the water.
lighter
A porous object absorb water and is heavier. In air the water is evaporated and the object become lighter.
the heavier object
Not a clue. Please Tell Me The Answer ?? :)
The object is actually lighter on the Sun
No. It becomes lighter as the water exerts an upthrust on the object according to the archmides' principle. Thus the reaction force ( or the weight ) of an object becomes less.
it is lighter than water.
I'm not exactly sure what you mean when you say "heavier" and "lighter". Does that mean the object's "weight" ? Could that be the same as the gravitational force on it ?
Depends on the solute: alcohol in water is lighter, salt in water is heavier than water.
When they're both at the same height, the heavier object has more gravitational potential energy.
Inertia
it is lighter or heavier