Why do planes leave trails? © Getty Images

Why do planes leave trails?

Come fly with me, let's fly, let's fly away!

Asked by: Pearl Goodwin, Lewes

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Technically known as contrails, these white trails are created from water vapour produced by the combustion of fuel in aircraft engines.

At their cruising altitude of 10,000m, temperatures are around -55°C. As it’s so cold, the water turns to ice particles, but how long they remain visible depends on humidity.

If the air is relatively humid, the contrails will grow and remain visible long 
after the aircraft has disappeared.


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