The cause of this phenomenon can be left to scientists to decide.
Fig. 22.—The obliging banana.
The Obliging Banana
It is rare that one can get a fruit so obliging as to peel itself, but upon certain occasions a banana will put itself out of the way to render this favor.
Cut off one end of a banana, and with a knife just start ripping up the skin on the four sides in the usual manner.
Now take an empty bottle, put some methylated spirit inside, and drop a lighted match to ignite the spirits. As soon as the flame has died out, place the prepared end of the banana in the mouth of the bottle, and you will find that the banana is slowly drawn inside, peeling off its skin as the fruit disappears ([Fig. 22]).
The reason for this condescension on the part of the banana is simple. As soon as the bottle begins to cool from the heat of the flames, the air is contracted inside, a vacuum is caused, and the fruit is sucked into the bottle.
The same trick can be performed with a water bottle and a shelled hard-boiled egg.