Why do lemons float while limes sink?

Few flavors complement each other like lemon and lime, with many a refreshing treat (hello, Sprite!) combining both for maximum effect. The two citrus fruits have some key differences, however, including the fact that limes sink while lemons float. You may have noticed this if you’ve ever put lime and lemon slices in a glass of water or cocktail, and the reason is simple: Objects only float if they’re less dense than the liquid they're placed in, and while both limes and lemons have densities close to that of water, limes are denser than their yellow counterparts. That remains true whether the lemon or lime in question is whole, peeled, or sliced — a lemon will always float, and a lime will always sink. 

That's not the only difference between these citrus fruits, of course. Whereas lemons grow well in moderate climates, limes fare better in tropical and subtropical areas. Limes also tend to be smaller, which helps distinguish them from lemons even when they sometimes take on a yellowish hue as they ripen. And though the two are almost identical on a nutritional level, lemons are sweeter — which is probably why you can think of a lot more lemon-flavored candies than lime-flavored ones.