Re: Apples & Humans may float or sink, depending on if they're alive or dead.

Hi Derek,

I'm not able to verify your claim of which items sink and which float (though I'm pretty sure fresh apples usually float), but whether something sinks or floats is not a function of whether it is new or old.

Instead, it is a property of density. Archimedes' principle says that an object submerged in a fluid receives a buoyant force equal to the weight of the fluid displaced. This buoyant force opposes the weight of the submerged object. An object with a certain volume that is fully submerged displaces the same amount of fluid. So, if that object has a higher overall density than that of the fluid, weight of the displaced fluid must be less than the weight of the object, which means it sinks. Conversely, if the object has a lower overall density than that of the fluid, the object floats.

So, it must be that fresh apples are less dense than water and that's why it floats.

I hope you stay curious about science.

Your MAD Scientist,
Raymond Cheong