An unpeeled orange floats in water.jpg

An unpeeled orange floats in water but it sinks when put after peeling.

In the same fashion we might have noticed a dry coconut with husk intact floating in water while the same coconut sinking when put in water after de-hulling the husk made of fibrous material.

We can even extend this comparison to see a ship or boat made of metallic sheets floating while the same metallic sheet when put in water sinking. Simple, straightforward explanation for these observations is that law of flotation is obeyed well for the cases of objects floating, no matter what the object is made of.

Any object put in water ( or any other liquid) displaces some amount of water (liquid) corresponding to its level of floating/immersion. If the weight of the water/liquid displaced is equal or more to the weight of the object, the object will float.

This is because of the buoyant force from the displaced water/liquid generating an upward lift acting on the object. It is common knowledge to experience an object being lifted easily when immersed in water than in normal condition.

Buoyant forces will be greater for objects which are less dense in comparison to that of water/liquid. In the case of unpeeled orange or dry coconut with husk they are lighter because of air entrapping by the outer most cover/husk causing them to be more voluminous, hence lighter so as to facilitate floating. When the cover is removed they sink because they become denser.