Have you ever watched an airplane fly across a clear blue sky? Sometimes it’s easy to trace an airplane’s path, because it leaves behind a white streak across the sky. After a while, though, the plane’s track fades and disappears into thin air.
Those white streaks planes leave behind are actually artificial clouds. They’re called contrails, which is a shortened version of the phrase “condensation trail.”
Airplane engines produce exhaust, just like car engines do. As hot exhaust gases escape from a plane, the water vapor in the fumes hits the air. At heights of 26,000 feet or more, the air is extremely cold (sometimes more than -40° F!).
The cold air causes the water vapor to condense. This means the water vapor gases turn into tiny water droplets or even freeze into tiny ice crystals before eventually evaporating. This condensed water vapor and mixture of ice crystals make up the cloud-like trails you see in the sky.
If you’ve ever seen an air show, you may have seen airplanes creating messages in the sky with what look like clouds. Are these contrails? Not exactly
