WHAT ARE THE WHITE SMOKE LINES THAT ARE LEFT BEHIND THE PLANES, ACROSS THE SKY ?
WHITE STREAKS THAT ARE LEFT BEHIND THE PLANES :
Some times we can see some white streaks in the sky. We all know that, they are the lines that are left behind the planes.So, it's very easy to find the planes path, because they left some white tracks behind them across the sky. But after wards, it will fade and dissapears.That white streaks, that are left behind the planes are actually artificial clouds and are called CONTRAILS.Shortened version of CONDENSATION TRAILS.
The reason for this formation of Contrails is, planes fly at a very high altitude of 26,000 feet and above. There, the temparature and air is very less. some times it will be more than -40°F. Generally planes exhaust hot humid gases.That exhaust contains carbondioxide, oxides of sulphur and nitrogen, un burned fuel, soot, metal particles and water vapour. The soot provides condensation sites for the water vapour. Any Particles present in the Air provide additional sites.That hot exhaust mixture, mixes with the cold air.The cold air causes water vapour to condense. It means the water vapour gases turned in to tiny water droplets or even Freeze in to tiny ice crystals before eventually Evaporating.This condensed water vapour and mixture of ice crystals makes the cloud like trails you see in the sky.
SOME PLANES LEAVE TRAILS AND SOME MAY NOT LEAVE.WHY ?
Reason for some planes leave streaks and some may not leave was, they may be in different regions of air.When the air is dry, the streak may not form and when the air is wet,then streak will form.If atmosphere is near saturation,then the condensed moisture caused by turbulence forms streak.
SOME CONTRAILS MAY LAST FOR LONG TIME AND AND SOME FADE FASTER:
some contrails fade away Quickly where as some contrails may persist and spread. One reason is it depends on the air in which they are formed in. Another reason is that, different planes have different Engines.Some Engines will not leave contrails and some other will leave contrail. Long lasting condensation contrails are CHEMTRAILS, consisting of chemical or biological agents left in the sky by high flying air crafts and air crafts emissions.
Depending up on the plane's altitude, temparature and humidity of the atmosphere, contrails my vary in their thickness, extent and duration.For example in a test conducted by German scientists to study contrail formation, AIRBUS A340 (Maiden Flight -1991) on the left ,leaving contrails and a BOEING 707 (Maiden flight1957) not leaving contrails. Both are flying at same height that is 33,000 feet. But the exhaust of the newer Engines A340 is at a lower temparature and so makes contrails in a wider range of conditions.
HOW STREAKS ARE HELPFUL TO DETECT CLIMATIC CONDITIONS:
The nature and persistance of jet contrails can be used to predict the weather. A thin, short lived contrail indicates low humidity air at high altitude. It is a sign of fair weather. Where as a thick, long lasting contrails reflect humid air as an early indicator of storm.The mixture of gases contained in the contrail rotate with respect for the ambient air. These regions of rotating flow are called vortices. Any sharp surface such as tip of a wing can cause vortical flow. On occasion, these vortices may interact with one another.
AIR CRAFT SHOWS :
Have you ever seen an air craft show creating messages in the sky, with what looks like clouds. They are not contrails. Those sky writers use some small air crafts equipped with special smoke machines to fly in special patterns to create written messages visible from the ground.The smoke machines usually consists of pressurised containers full of oil. At the pilots command, the machines spray oil in to the planes hot exhaust system,where it burns quickly and create clouds of dense white smoke.
But recent searches has suggested that, the ice clouds contained in the contrails cause Green House effect and will leads to Global Warming, because of insulating blanket of moisture and gases in the Atmosphere. Smoke less combustors helps to put an end to this Global Warming that was caused by planes.
The reason for this formation of Contrails is, planes fly at a very high altitude of 26,000 feet and above. There, the temparature and air is very less. some times it will be more than -40°F. Generally planes exhaust hot humid gases.That exhaust contains carbondioxide, oxides of sulphur and nitrogen, un burned fuel, soot, metal particles and water vapour. The soot provides condensation sites for the water vapour. Any Particles present in the Air provide additional sites.That hot exhaust mixture, mixes with the cold air.The cold air causes water vapour to condense. It means the water vapour gases turned in to tiny water droplets or even Freeze in to tiny ice crystals before eventually Evaporating.This condensed water vapour and mixture of ice crystals makes the cloud like trails you see in the sky.
SOME PLANES LEAVE TRAILS AND SOME MAY NOT LEAVE.WHY ?
Reason for some planes leave streaks and some may not leave was, they may be in different regions of air.When the air is dry, the streak may not form and when the air is wet,then streak will form.If atmosphere is near saturation,then the condensed moisture caused by turbulence forms streak.
Depending up on the plane's altitude, temparature and humidity of the atmosphere, contrails my vary in their thickness, extent and duration.For example in a test conducted by German scientists to study contrail formation, AIRBUS A340 (Maiden Flight -1991) on the left ,leaving contrails and a BOEING 707 (Maiden flight1957) not leaving contrails. Both are flying at same height that is 33,000 feet. But the exhaust of the newer Engines A340 is at a lower temparature and so makes contrails in a wider range of conditions.
The nature and persistance of jet contrails can be used to predict the weather. A thin, short lived contrail indicates low humidity air at high altitude. It is a sign of fair weather. Where as a thick, long lasting contrails reflect humid air as an early indicator of storm.The mixture of gases contained in the contrail rotate with respect for the ambient air. These regions of rotating flow are called vortices. Any sharp surface such as tip of a wing can cause vortical flow. On occasion, these vortices may interact with one another.
Have you ever seen an air craft show creating messages in the sky, with what looks like clouds. They are not contrails. Those sky writers use some small air crafts equipped with special smoke machines to fly in special patterns to create written messages visible from the ground.The smoke machines usually consists of pressurised containers full of oil. At the pilots command, the machines spray oil in to the planes hot exhaust system,where it burns quickly and create clouds of dense white smoke.
But recent searches has suggested that, the ice clouds contained in the contrails cause Green House effect and will leads to Global Warming, because of insulating blanket of moisture and gases in the Atmosphere. Smoke less combustors helps to put an end to this Global Warming that was caused by planes.
