Sippy Bird Experiments.

[Tom Booth]

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IMO gas molecules absolutely must have attractive forces that cause the group of molecules within a container or wherever, to come closer and closer together due to mutual attraction before finally coming close enough to condens into a liquid.

Molecules have a mutual attractive force. True. Gas molecules have relative velocities. If that velocity is above the 'escape velocity' they are gaseous. Below the escape velocity they tend to clump/liquefy. As two molecules get closer their mutual attraction makes their velocities increase. They accelerate towards each other. They get faster. Velocity is related to temperature. The funny thing is that escape velocity is higher when closer. So if below escape velocity, they tend to clump no matter how close they get or speed up from mutual attraction. If below the escape velocity, and they are clumping, they get close enough to have their repulsion kick in and effectively orbit each other, become liquid. Colder, they become solids, orbits become vibrations locked into positions.

There are several types of molecular bonding: ionic, covalent, Vanderwal, metallic, and hydrogen are some. They all have different strengths. Combined with size and pressure they dictate melting and boiling points.

If they are above the escape velocity, even if they are headed straight at each other, they will not clump. They will bounce off from each other's repulsive force, and keep going. This is true of identical molecules or different substances. They tend to trade energy's. Like a Newton's cradle. Trading kinetic energy is the transfer of heat. Heat is not the movement of molecules as often stated. Movement of molecules is internal energy, it is related to temperature. The attractive force, and repulsive force become transparent, and both are replaced by the bouncing force associated with energy and momentum.

The bouncing force added up is called pressure. There is talk of zero pressure in a vacuum, but it never quite gets there.

The velocity added up is called temperature. There is talk of zero temperature, but it never quite gets there

The range of travel, distance, is called volume. There is talk of zero volume in a vacuum, or at zero Kelvin, for an ideal gas, but never for a real gas. Real gasses have finite liquid and solid volumes.

Gasses don't liquefy because they get closer together, they liquefy because they get colder, slower. Pushing them together does increase that liquefaction temperature, but it increases temperature too. So pushing them together isn't likely to liquify them, unless cooled too.

So gases always push, are always present even when the liquid is smaller than the size of the container and also true of solids. That push just gets smaller, but never zero, even at very low temperatures. There is a sudden lowering change in pressure when a gas liquefies, (Can crush). Not so much when going from liquid to solid, but some can produce dramatic events, (Ice bomb).

As water vapor in a 55 gallon drum will condense (contract, draw together) into a liquid leaving a vacuum, so all gas molecules have mutual attraction and "contract", long before condensing into a liquid.

Yes. It is just overridden by the bounce force caused by being over the escape velocity, being hot and gasified.

Or do you suppose that a large volume of gas just suddenly ALL turns into a liquid without a gradual attraction drawing them closer and closer before finally condensing?

Yes. Except that gas molecules are always flying around each other, getting closer, bouncing off walls, bouncing off each other, getting further away, until they get cold enough, slow enough, to effectively spiral in, to an orbit. Example, cloud in a bottle.

https://m.youtube.com/watch?v=WeXuKd0vMRk

It may be the wrong video. I just copied it. Didn't watch it. Cloud forms suddenly by all the alcohol vapor turning suddenly into liquid droplets, no longer pushing, or pulling.


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You, as usual, detail a lot of "facts" which are nothing more than your own imagination/opinions.

Personally, I think condensation of water molecules in a 55 gallon drum is probably very gradual, just like condensation on the outside of a glass of ice water or lemonade on a hot summer day. The atmosphere around the glass of lemonade does not all condense suddenly.

The 55 gallon drum is very rigid and strong and resists collapsing for a long time as it is cooled down more and more and as more and more water vapor condenses into liquid.

As more and more liquid condenses the pressure drops.

Eventually, once the pressure is very low the steel drum finally fails and the collapse is very sudden

The same thing would happen if you gradually removed all the air with a vacuum pump. The removal of air would be gradual, and the pressure drop gradual, but the collapse of the drum very sudden. This has been demonstrated.

So, the water molecules in the drum attract each other and condense into liquid leaving more and more of a partial vacuum, similar to a vacuum pump, until enough water condenses to create a strong enough vacuum to collapse the drum.

If a pressure gage were attached to the 55 gallon drum during these experiments, I'm pretty sure it would show a gradual lowering in pressure as the molecules were more and more attracted and no longer impacting the drum walls. Or put another way, the kinetic energy reduced by impact with the cold metal so the attractive force becomes dominant.

With a viewing glass or camera in the drum, probably some liquid would be seen condensing on the interior drum walls before the volume of the drum decreased due to failure and collapse.

Molecules attract in a vacuum, or the molecules in the vacuum of outer space would never have condensed into stars and planets.

OK so I'm just using my imagination also.

So, what do you think? What would a pressure gauge attached to the 55 gallon drum show? What would a camera inside show?

Gradual condensation? Gradual pressure drop? Or some sudden snap where ALL the water condenses simultaneously as you say "like the cloud in a bottle"?

Many gases certainly do condense under pressure without cooling. You apparently don't know much about the history of the liquefaction of gases.

Anyway, all these questions could be settled experimentally.

[Tom Booth]

Actually, IMO kinetic theory of gases is mostly mythology.

I think gases are mostly stationary or "vibrating" in place, much like a solid lattice crystal. The forces of attraction and repulsion in perfect balance if left undisturbed.

Consider for example a layer of cold dense air below a layer of warmer air.

If left undisturbed by outside forces they remain separated.

If the gases were zipping around at the speed of sound in straight lines the layers of warmer and colder gas would become mixed almost instantly at the speed of sound, but they don't. Unless otherwise disturbed by some outside force , the layers can remain separated indefinitely. There is no straight line movement of the gas molecules from one layer into the other layer.

[Tom Booth]

What has this got to do with "escape velocity"?:

Resize_20241005_135628_8809.jpg (187.91 KiB) Viewed 757 times

https://ecampusontario.pressbooks.pub/c ... -behavior/

So how many gases are "ideal" and have no attraction?

How many gases are real and do?

[Tom Booth]

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If they are above the escape velocity, even if they are headed straight at each other, they will not clump. They will bounce .... They tend to trade energy's. Like a Newton's cradle. Trading kinetic energy is the transfer of heat. Heat is not the movement of molecules as often stated. Movement of molecules is internal energy, it is related to temperature. The attractive force, and repulsive force become transparent, and both are replaced by the bouncing force associated with energy and momentum.

The bouncing force added up is called pressure. ....

You seem to be mostly rambling incoherently, but the reference to Newton's Cradle relating to gas molecules is interesting.

Newton's Cradle, the actual device or demonstration model with the metal balls is far from the kinetic theory picture of gas molecules in random motion at high velocity. You elsewhere talk about "escape.velocity", so which is it?

More like a lattice of tightly packed molecules, as in a crystal or other solid, just not bound together as tightly.

So, how does heat or sound propagate through air if the molecules are zipping around in random motion? If that were true the energy of sound waves would not propagate in any coherent way.

Heat conducted through air doesn't travel far before convection currents kick in. Sound, though, travels great distances through air, apparently similar to how energy travels through a Newton's Cradle.

So, I would tend to conclude that ordinary air molecules in the atmosphere are only marginally more free to move around than a liquid or solid. They are not tightly bound together but they don't seem to actually be zipping around at the speed of sound either, The atmosphere or air/gas generally seems more like a nearly "solid" sea of Newton's Cradle balls, held in position, not by string, but just by gravity and their own balance of attraction and repulsion forces.

Kind of like one of those pools full of balls kids play in

https://youtu.be/0hgIX1jhyQk


The gas molecules, like the balls in the ball pit don't move around or fly around at high velocity, they just sit there neatly but loosely packed together or arranged in an orderly "crystal"- like pattern until disturbed.

[Tom Booth]

I actually found the above frustrating in various experiments attempting to get heat to flow into a "cold hole" to power a Stirling engine "running on ice".

If you put the engine on ice and insulated the ice and the bottom of the engine, the engine tends to get "cold soaked".

The heat does not aggressively try to leave the air above the engine and "flow down" through the engine into the ice.

Only the motion of the displacer keeps the air in motion so the engine runs at all.

If the engine is stopped for some time, it may not start back up easily at all, because the gas inside the engine tends to get cold and pool inside the engine like the ball pit.

The heat in the air above the engine apparently feels no "attraction" or inclination to "flow" down, through the engine into the "cold hole" region below the engine and into the ice.

Carnot and Kelvin etc. thought heat flowed down from hot to cold like water, and Tesla counted on this tendency as the power source for his "self acting engine", but such a force or tendency doesn't appear to actually exist as far as I can tell.

[Fool]

Personally, I think condensation of water molecules in a 55 gallon drum is probably very gradual, just like condensation on the outside of a glass of ice water or lemonade on a hot summer day.

I can agree with that. At 4 in the morning it's hard to say everything correct. It's always been my contention that barrel and can crushing is more a factor of container resistance change. Weaker as it begins to crush.

I don't see how a ball pit is analogous to a gas, but I do see the comparison to a pool of water.

What you are thinking about, is mean free path. How far a gas molecule travels before bouncing off another.

I googled it and got the following to come up.

Flexi Says: The average distance a gas molecule travels between collisions is known as the mean free path. The exact distance varies depending on factors such as the temperature, pressure, and type of gas. However, for air at room temperature and atmospheric pressure, the mean free path is approximately 68 nanometers.

It suggests that the mean free path gets longer as the pressure drops and temperature rises. I'm wondering how the distance relates to density. Density is related to closeness and size of molecule.

Solid is locked in crystallin form with vibration.

Liquid allows flow of molecules, but still bonded with vibration.

Gas has a separation, no longer bonded with free path and ability to escape. It must be contained in some manner or fly off into a vacuum forever.

It is not surprising to me that gasses respond to gravity and pool onto large planets. That is a form of containment. They have reached the escape velocity of each other but not the planetary escape velocity.

It is not surprising to me that heat, or at least hot and cold gases and liquids are effected by gravity. It's called natural convection. Try putting hot and cold blocks of copper together and see which way heat travels.


https://en.m.wikipedia.org/wiki/Escape_velocity

For a substance to exist as a gas, its molecules need to be moving at a speed where they can overcome the intermolecular forces holding them together, which typically requires an average molecular speed in the range of hundreds of meters per second depending on the substance and temperature involved; the exact speed depends on the molecule's mass and the temperature

The difference between liquid and gas is that the gas is free to travel, no longer bonded. Always has a pushing pressure. Expands to fill it's container.

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[Fool]

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Many gases certainly do condense under pressure without cooling. You apparently don't know much about the history of the liquefaction of gases.

Liquefaction of gasses requires cooling. Propane, if compressed suffers from adiabatic temperature increase. It won't liquify if at a hotter temperature. It must be cooled, necessary to keep it at room temperature during compression.

https://m.youtube.com/watch?v=EaMfykiEYNc

Heat of compression prevents gas from liquefying by compression alone. Heat can be removed isothermally at room temperature, if compression is slow enough.

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[Fool]

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Newton's Cradle, the actual device or demonstration model with the metal balls is far from the kinetic theory picture of gas molecules in random motion at high velocity. You elsewhere talk about "escape.velocity", so which is it?

The analogy of Newtons cradle breaks down when put in a vacuum. Go figure. Gases have greater than escape velocity and expand forever. Newtons cradle has leashes.

It is interesting to put a solid, liquid and gas, in a vacuum to see how the differ. Take water, ice and, steam.

The steam gets sucked away immediately and disappears down the vacuum hose to be exhausted outside.

The ice dries up by subliming directly from solid to vapor/steam. It gets colder.

The water starts boiling turning also into steam, but faster than ice. It gets colder. In fact it will keep getting colder even when ice starts forming in the boiling pool. Ice water and steam all from the same pool.

I suppose the question involved here regarding attraction and bonding would be how is it possible for all three to be bonded and only one, vapor/steam able to move by vacuum out of the chamber. Ice just sits there not showing any motion, just getting smaller. Water shows active boiling and freezing motion, but stays relatively pooled up. Somehow it just can't fully be attributed to locked-in-bonded-vibration. Water bonds move but don't let go. Vapor/steam very obviously let's go until bouncing off of something else, like a wall, or other molecule.

Since molecules of air are continuously bouncing off each other, a sound wave easily propagates through by producing a slightly modified coordinated group bounce effort, as it travels through in the direction of the sound wave before deciding back into the original random bouncing and moving.

Think about Brownian motion and how a bunch of collision can move a particle all around inside a stationary jar of liquid.

Solid is crystalline. Has a hold.

Liquid is in orbit. Juggling.

Gas is above the escape velocity. Watching them zip by and impacting, producing pressure always.



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[Tom Booth]

Personally, I think condensation of water molecules in a 55 gallon drum is probably very gradual, just like condensation on the outside of a glass of ice water or lemonade on a hot summer day.

I can agree with that. At 4 in the morning it's hard to say everything correct. It's always been my contention that barrel and can crushing is more a factor of container resistance change. Weaker as it begins to crush.

I don't see how a ball pit is analogous to a gas, but I do see the comparison to a pool of water.

What you are thinking about, is mean free path. How far a gas molecule travels before bouncing off another.

I googled it and got the following to come up.

Flexi Says: The average distance a gas molecule travels between collisions is known as the mean free path. The exact distance varies depending on factors such as the temperature, pressure, and type of gas. However, for air at room temperature and atmospheric pressure, the mean free path is approximately 68 nanometers.

It suggests that the mean free path gets longer as the pressure drops and temperature rises. I'm wondering how the distance relates to density. Density is related to closeness and size of molecule.

Solid is locked in crystallin form with vibration.

Liquid allows flow of molecules, but still bonded with vibration.

Gas has a separation, no longer bonded with free path and ability to escape. It must be contained in some manner or fly off into a vacuum forever.

It is not surprising to me that gasses respond to gravity and pool onto large planets. That is a form of containment. They have reached the escape velocity of each other but not the planetary escape velocity.

It is not surprising to me that heat, or at least hot and cold gases and liquids are effected by gravity. It's called natural convection. Try putting hot and cold blocks of copper together and see which way heat travels.


https://en.m.wikipedia.org/wiki/Escape_velocity

For a substance to exist as a gas, its molecules need to be moving at a speed where they can overcome the intermolecular forces holding them together, which typically requires an average molecular speed in the range of hundreds of meters per second depending on the substance and temperature involved; the exact speed depends on the molecule's mass and the temperature

The difference between liquid and gas is that the gas is free to travel, no longer bonded. Always has a pushing pressure. Expands to fill it's container.

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To put that into perspective, as per your reference, 68 nanometers is about 1500 times smaller than the average width of a human hair.

Relatively speaking I would consider that tightly packed and virtually unable to move at all without bumping into a neighboring gas molecules less than 1000th the width of a human hair away.

If you factor in that the gas molecules are held apart by the balance of attractive and repulsive molecular forces, are they actually moving, relative to one another, even the 1/1000th or less distance of a human hair?

How many human hairs do you need to stack up to reach from the hot plate to the piston in a Stirling engine?

[Tom Booth]

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Many gases certainly do condense under pressure without cooling. You apparently don't know much about the history of the liquefaction of gases.

Liquefaction of gasses requires cooling. Propane, if compressed suffers from adiabatic temperature increase. It won't liquify if at a hotter temperature. It must be cooled, necessary to keep it at room temperature during compression.

https://m.youtube.com/watch?v=EaMfykiEYNc

Heat of compression prevents gas from liquefying by compression alone. Heat can be removed isothermally at room temperature, if compression is slow enough.

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If you compress a gas at room temperature and it heats up, loosing energy to the surroundings, I would not say that is you "cooling" the gas. It isn't being "cooled" or getting any colder than the temperature it started at. If compressed "isothermally" it doesn't get any hotter either.

If the gas is already below it's critical temperature then it can be liquified by pressure alone. It depends on the gas.

[Tom Booth]

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Newton's Cradle, the actual device or demonstration model with the metal balls is far from the kinetic theory picture of gas molecules in random motion at high velocity. You elsewhere talk about "escape.velocity", so which is it?

The analogy of Newtons cradle breaks down when put in a vacuum. Go figure. Gases have greater than escape velocity and expand forever. Newtons cradle has leashes.

It is interesting to put a solid, liquid and gas, in a vacuum to see how the differ. Take water, ice and, steam.

The steam gets sucked away immediately and disappears down the vacuum hose to be exhausted outside.

The ice dries up by subliming directly from solid to vapor/steam. It gets colder.

The water starts boiling turning also into steam, but faster than ice. It gets colder. In fact it will keep getting colder even when ice starts forming in the boiling pool. Ice water and steam all from the same pool.

I suppose the question involved here regarding attraction and bonding would be how is it possible for all three to be bonded and only one, vapor/steam able to move by vacuum out of the chamber. Ice just sits there not showing any motion, just getting smaller. Water shows active boiling and freezing motion, but stays relatively pooled up. Somehow it just can't fully be attributed to locked-in-bonded-vibration. Water bonds move but don't let go. Vapor/steam very obviously let's go until bouncing off of something else, like a wall, or other molecule.

Since molecules of air are continuously bouncing off each other, a sound wave easily propagates through by producing a slightly modified coordinated group bounce effort, as it travels through in the direction of the sound wave before deciding back into the original random bouncing and moving.

Think about Brownian motion and how a bunch of collision can move a particle all around inside a stationary jar of liquid.

Solid is crystalline. Has a hold.

Liquid is in orbit. Juggling.

Gas is above the escape velocity. Watching them zip by and impacting, producing pressure always.



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A Newton's Cradle cannot work to propagate energy unless the balls are all in close contact.

I would assume a similar condition, close contact between air molecules, is necessary for the propagation of sound.

Does sound travel in a vacuum, or even a partial vacuum?

https://youtu.be/YxUERaXBAU8

Your supposed: " ...slightly modified coordinated group bounce effort, as it travels through in the direction of the sound wave before deciding back into the original random bouncing and moving...." Is just your own fanciful imagination and a bit ridiculous IMO.

[matt brown]

To put that into perspective, as per your reference, 68 nanometers is about 1500 times smaller than the average width of a human hair.

Relatively speaking I would consider that tightly packed and virtually unable to move at all without bumping into a neighboring gas molecules less than 1000th the width of a human hair away.

If you factor in that the gas molecules are held apart by the balance of attractive and repulsive molecular forces, are they actually moving, relative to one another, even the 1/1000th or less distance of a human hair?

How many human hairs do you need to stack up to reach from the hot plate to the piston in a Stirling engine?

Or...what is the density of a gas measured via (distance between molecules)/(size of molecules) ??? Hint...if 1 mole of gas in 1 cubic meter container had ALL the space between the molecules removed, you still couldn't see this mole in any corner of this container. What we call "air" is more vacuum than not...

[matt brown]

Gas has a separation, no longer bonded with free path and ability to escape. It must be contained in some manner or fly off into a vacuum forever.

It is not surprising to me that gasses respond to gravity and pool onto large planets. That is a form of containment. They have reached the escape velocity of each other but not the planetary escape velocity.

It is not surprising to me that heat, or at least hot and cold gases and liquids are effected by gravity. It's called natural convection. Try putting hot and cold blocks of copper together and see which way heat travels.

Fool - did you ever consider exactly how hot air rises in a room with a floor heater ?

We all know that a hot air balloon rises when the weight of contained hot air + basket etc < displaced ambient air (akin Archimedes' buoyancy principle).

However, the room lacks any containment between hot and cold air, so how/why does hot air rise in room ? IOW when 2 equal sealed containers are filled with equal gas mass, both containers weigh equal despite any temperature difference. So, the weight of a gas molecule is independent of temperature or is it ??? - LOL

[Tom Booth]

To put that into perspective, as per your reference, 68 nanometers is about 1500 times smaller than the average width of a human hair.

Relatively speaking I would consider that tightly packed and virtually unable to move at all without bumping into a neighboring gas molecules less than 1000th the width of a human hair away.

If you factor in that the gas molecules are held apart by the balance of attractive and repulsive molecular forces, are they actually moving, relative to one another, even the 1/1000th or less distance of a human hair?

How many human hairs do you need to stack up to reach from the hot plate to the piston in a Stirling engine?

Or...what is the density of a gas measured via (distance between molecules)/(size of molecules) ??? Hint...if 1 mole of gas in 1 cubic meter container had ALL the space between the molecules removed, you still couldn't see this mole in any corner of this container. What we call "air" is more vacuum than not...

I think this debate began in connection with cooling the gas in a 55 gallon drum and the question, does the gas in the drum "contract" or condense into a liquid before the drum collapses.

Given the relatively limited sphere of influence of a gas molecules inside a drum without much outside influence, like wind to disturb it, I don't see that cooling the outer "skin" of the volume of gas in contact with the interior walls of the drum would have any direct influence on the gas towards the middle interior.

So, probably some gas in contact with the drum interior walls cools, condenses and due to mutual attraction, possibly liquefies almost immediately, while the gas molecules a few nanometers further in towards the interior are unaffected other than experiencing a pressure drop and more freedom of movement.

The gas that "contracts", initially, did not do so as a result of external atmospheric pressure. The molecules cooled and contracted, in spite of having to create more and more of a partial vacuum to do so.

The point is, gas particles DO have forces of attraction that brings them together even above "escape velocity". Even as gases, not liquids or solids. The kinetic model of gases moving in straight lines without ever influencing each other, without mutual attraction and repulsion is a convenient "idealization" for simplifying some mathematical approximations but is mostly fiction. Actual gas molecules do have attraction, do "contract" or condense leaving a vacuum, even inside a rigid container under the right conditions, they do not automatically "expand to fill the container" if attractive forces dominate.

But, I could be wrong

The drum "implosion" appears to happen very suddenly without warning, causing shock, screams and gasps in the observers, so, maybe somebody should attach a pressure gauge to the drum and find out.

[Tom Booth]

Here's one video using a vacuum pump.

Same sudden implosion, though the pressure drop must certainly have been very gradual:

https://youtu.be/j3tqK6thgqU

Another with a gauge:

https://youtu.be/CONxG2Kb160

One more:

https://youtu.be/ogY7rRIdrxI