There is an Eureka can and an object is put on it.

• If the object is floating, then there is no weight difference for the water container. ($latex G=F_k$)
• If the object is fully submerged, then the water container is getting heavier since no more bouyancy force is equal to the weight of the object. ($latex G>F_k $). It will be $latex G-F_k $ heavier than before.
• If the object floating in its own liqud, (e.g. ice in water) then if the solid part melts the liquid level does not change.