How it works
An object floats when it displaces enough water for buoyant force to balance its weight. Apple variety and internal structure affect how high it sits.
What people often miss
The common claim that every apple is exactly one-quarter air is too precise for all varieties. The important fact is that the combined fruit and air are less dense than water.
Why this question comes up
The property makes apple bobbing possible and demonstrates buoyancy with ordinary food.
Key points
- Apples float because their average density is lower than water, largely due to air spaces within the fruit's tissue.
- An object floats when it displaces enough water for buoyant force to balance its weight. Apple variety and internal structure affect how high it sits.
- The common claim that every apple is exactly one-quarter air is too precise for all varieties. The important fact is that the combined fruit and air are less dense than water.
Bottom line
Apples float because their average density is lower than water, largely due to air spaces within the fruit's tissue.
Source and verification
This Answer was checked against U.S. Geological Survey Water Science School. Follow the source for the full official explanation and any later updates.