Bananas float in water because they are less dense than water. Also, fruits like watermelons, apples and oranges float in water because they have so many air pockets in them.
Many people think that bananas only float in seawater due to the salt content. The truth is that bananas first sink a little bit in freshwater but then pop right back up to the surface.
Although bananas are actually 75 percent water, they contain many nutrients, including vitamin C, potassium, fiber and vitamin B6 but no cholesterol, fat or sodium. Even the insides of banana peels are useful and can be used to whiten teeth, alleviate itching from insect bites and polish silver.