Why Do Fruits Ripen Faster Near Other Fruit?

Imagine you have a group of friends. If one friend starts laughing hard, the others might start giggling too, even if they do not know why. Fruit does something similar with a tiny invisible helper called ethylene gas.

Some fruits, like bananas and apples, naturally blow out small bubbles of this gas as they grow older. This gas is like a little alarm clock or a chef's whistle. When other nearby fruits smell (or rather, sense) this gas, it tells them, "Hey, it is time to get soft and sweet!"

You have probably seen people put bananas in a paper bag. This traps the ethylene gas inside so the bananas cannot escape. Because they are surrounded by their own gas, they ripen much faster than if they were left sitting out on the counter.

If you leave an apple and a pear together, the apple will keep blowing ethylene gas at the pear. The pear will think it is time to eat and become mushy while waiting for someone. This is why we say "one bad apple can spoil the bunch." They are just too good at communicating with each other.