# Why certain planes flying high in sky leave a trail of smoke behind them?

These Planes flying very high in sky and leaving behind them a trail of smoke called ‘jet’ are called ‘Jet planes’. This ‘Jet’ is a heavy smoke trail that comes out of the near portion of the plane with high speed.

Jet plane flies at a greater height from earth in the sky with greater speed when compared with the ordinary aero plane. Jet plane acquires greater speeds because of the Jet of smoke emitted from it’s near.

According to Newton’s third law of motion, we know that for every action there is an equal and opposite reaction for example if we blow air into a rubber balloon and leave it, we observe the air rushes out of its mouth speedily and at the same time, the balloon runs in the opposite direction. Basing on this principle only the get planes and the rockets function.

In the near portion of a Jet plane there will be an arrangement which sucks air from the atmosphere into a large portion.

A very high pressure is applied on that air in the compartment because of which the temperature of that increases. A fuel like petrol or diesel is burnt in that compartment. The fuel thus burnt rushes out of the near portion of the plane in the form vapor (Jet) speedily as air rushes out of a blown balloon. The reaction force due to the speed of the ‘Jet’, the plane moves forward speedily. As the intensity of air in the atmosphere at greater heights where the Jet planes fly is very less, the ‘Jet’ emitted by the plane will not be scattered here and there and remain in the sky for longer period steadily. Even after the Jet plane fly off from that place.

As the fuel burnt in a Jet plane is less in quantity, greater speeds can be acquired with less expenditure. Jet planes are used to travel long distances with minimum stops.
Prof: Laxmi… Emani
Published date : 13 Mar 2013 05:48PM