why do some airoplanes have white trails that stay in the sky for ages and can form clouds, when others dont?

Answer 1

It's all in how many people flush the toilet

Answer 2

Not aeroplanes but JET ENGINES would be more appropriate.

The clouds that these aeroplanes form are called condensation trails or contrails. ON some days, the contrails will form thin lines that cross the entire sky whereas on other days they will be much shorter, and on some days there will be none at all.

A contrail forms because one of the components of jet engine of the aeroplane exhaust is water. Jet fuel is made of carbon and hydrogen. When jet fuel burns with oxygen, most of the exhaust consists of CO2 (carbon dioxide) and H2O (water). The water is generally an invisible vapor.

When we exhale, our breath contains a great deal of invisible water vapor as well. You may have noticed that on certain days in the winter, your breath will form a cloud of condensation when you exhale. In the summer, however, you don't see your breath. Cold air can hold a lot less moisture than warm air, so in the winter, when the moisture in your breath hits the cold air, the moisture condenses into a visible cloud.

The same thing happens when a jet engine exhales" If the temperature, winds and humidity in the upper atmosphere are right, long, white contrails form when the moisture in the exhaust condenses.

Answer 3

Most of the above answers are mainly correct as to what causes these. It is water vapor or water vapor converted to ice crystals.

Contrails are only created from the engines (usually turbine but yes WWII bombers flew so high their engines did this as well). It happens. The process happens when the engine exhaust increases the water content in the air past the saturation point (pretty easy at high altitude). This turns to ice crystals at such low temperatures that is why the really high ones tend to stick around a long time and sometimes catalyze a cloud.

Why some do and some don't? A bunch of reasons:
- Different altitude (hard to judge when you are on the ground).
- Different exhaust temperatures
- High by-pass or low by-pass engine (low by-pass will create larger/longer contrails)

Answer 4

Jet aircraft flying above the mintra level (altitude above which water vapour freezes and forms crystals) create vapour trails formed from the water content in their exhaust gases, known as 'contrails'. If the wind does not blow them away, they may stay on for some time, otherwise they disperse and become invisible.

Aircraft flying below the mintra levels donot create these contrails.

Watching from the ground, you may not be able to discern the altitude of various aircraft flying around, thus the illusion that some create contrails and some do not.

Answer 5

Drewpie and Ugly M are the best answers. All the others aren't really correct or left out a lot of info. Although if your a conspiracy believer then the first answer could also be correct in addition to the other two.

Answer 6

Condensation trails some times called contrails. Are altitude and air temp dependent. Some times 20,000 feet is not cold enough and 35,000 feet is cold enough to freeze the jet exhaust's water vapor.

Answer 7

Because the planes that leave the most deffinate lines and the lines that last longer are up higher, the higher the altitude the oxygen becomes less dense, and if there is no oxgen to either blow it away, or filter it it will float there weightlessly, and of course what ever is hot floats upward.

Answer 8

they are commonly referred to as con-trails. they are formed by exhaust gases. if conditions are right they will hang there. such as hot enough exhaust gas, relative humidity and winds as cruising altitude. if the wind is too high it will blow them away before they are visible from the ground

Answer 9

it is a vapour trail
the fuel mixes with the water vapour
so it makes a cloud
but the cloud only forms where the fuel is so it makes the nice line across the sky
hope that helps

Answer 10

Depends on how much moisture is in the atmosphere. When there's little moisture you don't get vapour trails, when there's a lot, you do.