Contrail

Okay kiddo, let me explain to you what a contrail is. Have you ever seen an airplane flying in the sky and noticed a white line behind it? That line is called a contrail.

When the airplane flies, it burns fuel, and part of that fuel is a gas called methane. Oxygen from the air reacts with the methane and produces carbon dioxide and water vapor. The water vapor then mixes with the cold air, forming tiny ice crystals.

These ice crystals create the white line that we see behind the airplane. This line sometimes stays in the air for a while, and sometimes it disappears quickly.

So, next time you see an airplane in the sky with a white line behind it, you'll remember that it's called a contrail and how it's formed by the airplane's engine using air and fuel to create ice crystals.