How do airplanes/jets effect the atmosphere?

He seems to be saying that a piece of metal will start collecting moisture as it is being heated.

 

It is not actually the metal "collecting" moisture, it is the chemical reaction between the material (Metal) being heated and the fuel source being used to do so. The release of H2O does indeed create condensation in this process which one could say is due to the metal, but not the metal alone.

 

hmm. this makes no sense to me. How is water to condense on a hot piece of metal?
What reaction speaketh thou of?

 

Here is the textbook explanation:

"Moisture is given off in many different processes. Human beings give off a significant amount of water through respiration and perspiration. There are other common sources. Gas, oil-fired and propane space heaters give off a significant amount of moisture through the process of combustion. The moisture introduced through combustion is sometimes very difficult to detect because at the point of combustion, the gases are very hot and can hold large quantities of moisture. When this hot gas is mixed with cooler air, the temperature drops. As the temperature drops, the amount of moisture that the gas can hold will decrease and at some point away from the combustion device, the water will condense on anything that it comes in contact with that is below the dew point of that mixture. Flue gases should be vented outside to prevent this from happening."

 

Ok all kind of obvious, I guess we need to know just how hot this metal is that he is talking about.

The proposed principle that "heat causes condensation" is backwards in any case.

 

Actually, heat is "Required" for condensation to occur, as is the lack of it. Water vapor will condense due to differences in the temperatures of materials. When heating a metal the process is relatively slow and goes through many temperature variations...though I doubt he has seen condensation once a metal approaches the melting point.

 

Only in the sense that heat causes applesauce, its a part of everything that happens.

 

If you simply place carbon and oxygen in a container they won't create H2O...right or wrong?

Carbon and oxygen contain no H2O...right?

In regards to the atmosphere, doesn't water vapor stem from evaporation? Liquid water evaporates as water vapor into the atmosphere.

When carbon/fuel is burned or heated, as with a jet engine, increasing the air temperature then cooling, isn't this the point where condensation occurs?

 

A reduction in heat in an environment with invisible moisture can cause the water to condense into visible moisture, so what's the difference? It's called dew point. It's how clouds form.

 

I usually cut different thicknesses of metals. A36 structural steel is the most common... from 1/2 inch thick to 3 inches thick normally. For thinner metals and stainless I use plasma. Water will condense on the metal while pre-heating (you must pre-heat in order to blow through) and sometimes water condenses in front of the torch while burning. I burn 1/2 inch at 18 inches per minute and thicker metals slower. The fuel for the torch is propane and O2.

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I usually cut different thicknesses of metals. A36 structural steel is the most common... from 1/2 inch thick to 3 inches thick normally. For thinner metals and stainless I use plasma. Water will condense on the metal while pre-heating (you must pre-heat in order to blow through) and sometimes water condenses in front of the torch while burning. I burn 1/2 inch at 18 inches per minute and thicker metals slower. The fuel for the torch is propane and O2.

 

The preheat allows for the condensation....to answer your question.

 

We still dont have an explanation for this,how it works.

 

The warm air from the torch meets the cool air from the atmosphere causing condensation. I got this from a Faraday lecture.



Lecture III.—it quite full of steam to have it sent out in that great quantity. And now, as we can convert the water into steam by heat, we convert it back into liquid water by the application of cold. And if we take a glass, or any other cold thing, and hold it over this steam, see how soon it gets damp with water: it will condense it until the glass is warm—it condenses the water which is now running down the sides of it. I have here another experiment to show the condensation of water from a vaporous state back into a liquid state, in the same way as the vapor, one of the products of the candle, was condensed against the bottom of the dish and obtained in the form of water; and to show you how truly and thoroughly these changes take place, I will take this tin flask, which is now full of steam, and close the top. We shall see what takes place when we cause this water or steam to return back to the fluid state by pouring some cold water on the outside. [The lecturer poured the cold water over the vessel, when it immediately collapsed (FIG. 66).] You see what has happened. If I had closed the stopper, and still kept the heat applied to it, it would have burst the vessel; yet, when the steam returns to the state of water, the vessel collapses, there being a vacuum produced inside by the condensation of the steam. I show you these experiments for the purpose of pointing out that in all these occurrences there is nothing that changes the water into any other thing; it still remains water; and so the vessel is obliged to give way, and is crushed inward, as in the other case, by the farther application of heat, it

Note 1. Water is in its densest state at a temperature of 39.1° Fahrenheit. [back]
Note 2. A mixture of salt and pounded ice reduces the temperature from 32° F. to zero, the ice at the same time becoming fluid. [back]
Note 3. Potassium, the metallic basis of potash, was discovered by Sir Humphry Davy in 1807, who succeeded in separating it from potash by means of a powerful voltaic battery. Its great affinity for oxygen causes it to decompose water with evolution of hydrogen, which takes fire with the heat produced. [back]
Note 4. [Greek], “water,” and [Greek], “I generate.” [back]
Note 5. Professor Faraday has calculated that there is as much electricity required to decompose one grain of water as there is in a very powerful flash of lightning. [back]

 

Gotta admit, no heat/no condensation. It's part of the equation.

 

Ok well, then heat causes computers too. Got it.

 

You may have also seen a stream of vapour coming off the wing tips of a jet when you looked out the window. This is some sort of compression / turbulence, not related to the exhaust as such.

That is related to humidity in the air and the low pressure vortices sliding off the wing tips which are always there when the wings are generating lift. The vapor disappears as soon as the wheels touch down.