Science Insider
Did you know that an unpeeled orange floats on water while a peeled orange sinks?
Vidunenahawula Website (National Institute of Fundamental Studies)

Did you know that an unpeeled orange floats on water while a peeled orange sinks? This happens because the unpeeled orange has a porous peel which contains tiny air pockets. These air pockets make the orange seem less dense than water, causing it to float. Removing the peel removes the air pockets and makes the peeled orange denser than water so, it floats.