Why do apples float?
Apples float because about a quarter of their volume is air, trapped between their cells. This makes them less dense than water, so they bob on the surface.
An object floats if it is less dense than the liquid it is placed in. Fresh apples contain about 20 to 25 percent air, which gives them a density lower than water. The air is stored in spaces between the cells of the apple's flesh. Pears, by contrast, are denser and often sink.
This property makes apple bobbing possible. In this traditional game, especially popular at Halloween, players try to catch apples floating in a tub of water using only their teeth. The game is linked to old harvest festivals in Britain and Ireland.
Other floating foods
Many fruits and vegetables float, including oranges with their peel, bananas, lemons and watermelons. A peeled orange often sinks because the peel contains air pockets. A simple test for egg freshness uses the same principle: very old eggs float because air builds up inside them.
Did You Know?
Apples belong to the rose family, and there are more than 7,500 varieties grown around the world.