Apples Float Because 25% of Their Volume Is Air

The beloved autumn tradition of apple bobbing works because of a fascinating biological fact. Approximately 25% of an apple's volume is actually air trapped between its cells, making it less dense than water and allowing it to float. This air also gives apples their characteristic crisp texture when bitten.

This is why you can tell an old, mealy apple by squeezing it — as apples age, the cell walls break down and the air spaces fill with moisture, making them denser and less crisp. The same cellular structure that makes apples float also makes them perfect for juicing, as the trapped air can be pressed out along with the juice.