Do u know what’s the reason of white streak / Line across the sky in airplane’s path ?
That white streaks / Line from the planes are actually artificial clouds called contrails( condensation trail ).Simply It’s exact same principle as you blow out cold breath.
Airplane engines produce exhaust, just like motor car engines do. The exhaust has some of water vapor in it which mixes with the air when it leaves the jet’s engine. Sometimes this mixture has too much water vapor for the air to hold and it condenses into a cloud. At heights of plane path, the air is extremely cold.
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.
Based on the formation of white streaks / Line,There are two types of contrails. First one is what we mentioned above (Airplane engines produce exhaust is producing these streaks).This is the most common kind of contrail and it lasts the longest.
The second type of contrails are form by an airplane’s wing. Air moves over an airplane’s wings really fast and cools because of the low pressure. The cool air can’t hold as much water so some of it has to condense. This kind of contrail can’t as long-lived.
Contrails lasting time is depending on the atmospheric condition because when there is a greater amount of water in the air contrails lasts more time. During the summer season , the atmospheric has more water vapor than winter season. You might notice that it’s usually more humid in the summer. Because it’s more humid in the summer, contrails take longer to evaporate. That’s why they last longer in the Summer season.