Why Apples Float (And It's Not the Skin)

Added: 2026-05-21

[00:00:00]Drop an apple in a bowl of water and it bobs back to the surface like a cork.

[00:00:04]Have you ever wondered why?

[00:00:06]It is heavier than most things that float and it looks completely solid when you cut it open.

[00:00:12]There is nothing obviously buoyant about it, but every apple ever picked from a tree will float and there are three reasons for it. The first reason is hidden inside the fruit itself. An apple is about 25% air by volume. That air is not held in one big pocket. It is spread through tiny gaps between the cells of the flesh. If you look at a cross-section under a microscope, you can see them. Thousands of microscopic spaces like a sponge with very small holes.

[00:00:41]The flesh you bite into is mostly water and sugar and the rest is gas. That gas is what keeps the whole fruit lighter than the water surrounding it.

[00:00:51]The second reason is density. Water has a density of 1 g per cubic centimeter.

[00:00:56]Because of all that trapped air, an apple averages around 8/10 of a gram per cubic centimeter. Anything below one floats. The apple sits right at the boundary, which is why it bobs with the top quarter sticking out instead of riding high on the surface like a piece of Styrofoam. The dense water heavy part stays submerged and the air pockets keep just enough lift to break the water line. The third reason is evolution.

[00:01:22]Apples did not develop air pockets by accident. The wild ancestor of the modern apple grew in the forests of Central Asia in regions threaded with rivers and seasonal floods. A fruit that floats can drift downstream and plant its seeds somewhere new instead of rotting under the same tree that dropped it.

[00:01:43]Bears, deer, and horses helped spread apples by eating them and water carried the rest even further.

[00:01:50]The fruits that floated furthest left more descendants. So, over millions of years apples got more porous, lighter, and better at riding water.

[00:02:00]There is one more strange detail. As an apple ripens, its cell walls break down and let more air seep into the gaps. So, an apple that has been sitting in your fruit bowl for 2 weeks floats higher than one picked yesterday. The same fruit, slightly older, displacing the same water, suddenly more buoyant. That is also why bobbing for apples works at all. Old store apples float almost to the surface. A freshly picked Granny Smith barely breaks the water line.