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Old 18th April 2019, 10:03 AM   #321
Jack by the hedge
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Originally Posted by Gingervytes View Post
I already did. Pressure expand to least resistance and low pressure. Space provides no resistance and is near zero pressure
So at any given point in the exhaust stream from a rocket motor, the pressure gradient would be greater when operating in space, where the ambient pressure is zero, compared to in air where the ambient pressure is higher.

So the acceleration of the exhaust stream at each point will be higher. So its momentum will be higher. So the rocket works even better in space than in the atmosphere.

So?
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Old 18th April 2019, 10:04 AM   #322
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Originally Posted by Jack by the hedge View Post
This seems a perfect analogy.
Not only for the plausible-but-wrong explanation you gave, but for the purpose of establishing what constitutes a reasonable burden of proof. Just because a ship sails out of sight doesn't mean we can't draw reasonable conclusions about how it operates, nor that we cannot make other kinds of observations that would tend to confirm that operation in the way we predict.

Gingervytes is trying to defuse the effect of the testimony from people who work in the industry by splitting hairs between what they observed and what they might merely have inferred later. Your story and mine illustrate that his proposal is not a rational or useful standard of proof.
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Old 18th April 2019, 10:04 AM   #323
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Guys seriously don't do it. Don't argue the physics with someone who's denying space flight exists.

The physics aren't the problem, the reality denial is.
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Old 18th April 2019, 10:05 AM   #324
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Originally Posted by Gingervytes View Post
In the direction of low pressure...
So in a rocket thrust chamber, is there a difference in ambient pressure between the top (injector end) and the bottom (the nozzle throat)?
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Old 18th April 2019, 10:06 AM   #325
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Originally Posted by Gingervytes View Post
Campfire smoke pressure moves up because there is low pressure at higher altitude
How does the smoke know there's low pressure at high altitude, and why is smoke attracted to low pressure?
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Old 18th April 2019, 10:06 AM   #326
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Originally Posted by Gingervytes View Post
All the rockets ive seen, they don’t appear to go into space
Then you are quite wrong.

By the way, the Internet and GPS that you use are quite dependent upon satellite technology which was established by rockets going into space.
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Old 18th April 2019, 10:07 AM   #327
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Originally Posted by JoeMorgue View Post
The physics aren't the problem, the reality denial is.
Yes, he's seriously reality-challenged, but he claims physics is on his side. We're here voluntarily to show that it isn't. That's still a useful exercise. His refusal to answer the hard questions is an outcome favorable to that goal.
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Old 18th April 2019, 10:13 AM   #328
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Originally Posted by JayUtah View Post
It is my profession to do just that. Are you comfortable calling me a liar to my face?
No answer yet to this question. I claim I can put objects in space and then operate them Newtonially once they're there. Are you man enough to call me a liar based on your disbelief of such a claim?
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Old 18th April 2019, 10:14 AM   #329
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Originally Posted by Jack by the hedge View Post
How does the smoke know there's low pressure at high altitude, and why is smoke attracted to low pressure?
It might involve Craigslist.
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Old 18th April 2019, 10:21 AM   #330
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Originally Posted by Gingervytes View Post
In the direction of low pressure lol. Campfire smoke pressure moves up because there is low pressure at higher altitude
Nope. The pressure gradient is negligible at such a short distance.

Now, as to your claim that there’s no such thing as space travel:
Originally Posted by sts60 View Post
I’ve personally built (as part of a team), integrated, tested, observed the launch of, and operated spacecraft. Your claim is observed to be wrong.
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Old 18th April 2019, 10:29 AM   #331
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Originally Posted by Gingervytes View Post
In the direction of low pressure lol. Campfire smoke pressure moves up because there is low pressure at higher altitude
But what about the balloon? Would the toy balloon fly about if you opened the neck of the balloon in the vacuum of space?
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Old 18th April 2019, 10:34 AM   #332
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Originally Posted by Gingervytes View Post
In the direction of low pressure lol. Campfire smoke pressure moves up because there is low pressure at higher altitude
And what is the actual pressure difference between the atmosphere at campfire (ie ground) level and the atmosphere at 5 feet, 10 feet, 20 feet above ground level, that causes the smoke to rise so rapidly?
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Old 18th April 2019, 10:35 AM   #333
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With enough campfires, we could have a smoke ring around the equator, as if a big greedy capitalist with a cigar blew a smoke ring and turned earth into Saturn.
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Old 18th April 2019, 10:48 AM   #334
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Originally Posted by Meadmaker View Post
But what about the balloon? Would the toy balloon fly about if you opened the neck of the balloon in the vacuum of space?

According to the Stundie I quoted, the balloon would remain motionless as the vacuum sucked the air out of the balloon. I suspect that's where they're going.

It looks like a failure to understand the nature of privatives. Darkness doesn't absorb light, silence doesn't absorb sound, and vacuum doesn't absorb air.
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Old 18th April 2019, 10:53 AM   #335
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Originally Posted by Armitage72 View Post
It looks like a failure to understand the nature of privatives. Darkness doesn't absorb light, silence doesn't absorb sound, and vacuum doesn't absorb air.
Like how we tend to think of "cold" as some opposite natural force to "hot" because well that's sort of (very loosely) how it works on a practical real world level but "cold" isn't a thing like "hot" is.

Heat is (to grossly over simplify it) a measurement of active the molecules of a certain system are. "Cold" isn't something add to the system to make the molecules less active, it's just a handy, useful phrase for a system with less heat.

Sure it's perfectly fine on a practical level to conceptualize it as "My car is hot, I'm going to turn the 'cold' up" but in reality we never turn the 'cold' up, we can only turn the 'heat' down.

But yeah as you say cold/hot, silence/sound, dark/light, vacuum/atmosphere these are like... matter and anti-matter they are just scales with a straight measurement of a certain process happening that there can be more or less of but there's nothing like... operating in the other direction like a scale being balanced or whatever.
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Old 18th April 2019, 10:53 AM   #336
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Originally Posted by Gingervytes View Post
You know what I meant. Solid chunk is one piece. You could just say a piece of solid. I’m sorry that your English is weak
No I don't know what you mean, I can only read your written words.

I can't help the fact that you type stuff you don't mean.
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Old 18th April 2019, 10:55 AM   #337
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Originally Posted by Gingervytes View Post
Originally Posted by Mojo
Any chance of an answer to this question, Gingervytes?
I already did. Pressure expand to least resistance and low pressure. Space provides no resistance and is near zero pressure

The question was, “does the exhaust from a rocket expand equally in all directions?”

Is your answer to the question “yes”?
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Old 18th April 2019, 10:55 AM   #338
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Originally Posted by Gingervytes View Post
Hello,
Argument by YouTube video, that would mean you don't understand the concepts well enough to express them in written form.
Perhaps you don't even know what you think, you just believe.
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Old 18th April 2019, 10:57 AM   #339
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Originally Posted by Jack by the hedge View Post
How does the smoke know there's low pressure at high altitude, and why is smoke attracted to low pressure?

And why doesn’t all the air at ground level move up to higher altitude?
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Old 18th April 2019, 11:05 AM   #340
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Originally Posted by Mojo View Post
And why doesn’t all the air at ground level move up to higher altitude?
It does. But then the air realizes it's too high up and panics (Air is acrophobic. Must people don't know that because it doesn't come up a lot) so the air particles then jump back down to sea level before the hyperventilate from the stress, pushing the air particles lower to the ground up, starting the cycle all over again.

That's why you can hear wind, it's actually the tiny screaming of air particles. In Europe you can even tell the distinct accents on a windy day as you move from country to country. Except in one particular region of Southern France where technically you have to call it "Sparkling Screaming" instead of wind.

Of course in Australia in all happens backwards because of the Coriolis effect.
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Old 18th April 2019, 11:07 AM   #341
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Originally Posted by Gingervytes View Post
I already did. Pressure expand to least resistance and low pressure. Space provides no resistance and is near zero pressure
Sentence fragments do not a coherent argument make.
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Old 18th April 2019, 11:08 AM   #342
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Originally Posted by Gingervytes View Post
I already did. Pressure expand to least resistance and low pressure. Space provides no resistance and is near zero pressure
ONLY towards least resistance?
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Old 18th April 2019, 11:08 AM   #343
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Originally Posted by Meadmaker View Post
But what about the balloon? Would the toy balloon fly about if you opened the neck of the balloon in the vacuum of space?

That's a good question. Since it doesn't have anything to 'push' against, my guess is that Gingervytes will say no.
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Old 18th April 2019, 11:10 AM   #344
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Originally Posted by Gingervytes View Post
In the direction of low pressure lol. Campfire smoke pressure moves up because there is low pressure at higher altitude
Oh my, so buoyancy is another concept that is appear you misunderstand.

I am so surprised that hot air balloons don't leave the atmosphere!
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Old 18th April 2019, 11:11 AM   #345
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So spaceflight doesn't work because if energy isn't added to a system it will attempt to achieve equilibrium by all the internal parts of the system moving from a state of high pressure to low pressure but that can't work in space because "no pressure" isn't "low pressure" so the whole system falls apart.

Yeah that tracks.
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Old 18th April 2019, 11:12 AM   #346
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Originally Posted by Jack by the hedge View Post
How does the smoke know there's low pressure at high altitude, and why is smoke attracted to low pressure?
Because low pressure wears a nice outfit
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Old 18th April 2019, 11:14 AM   #347
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Originally Posted by Gingervytes View Post
In the direction of low pressure lol. Campfire smoke pressure moves up because there is low pressure at higher altitude
You are wrong again.

The reason why the smoke moves up is because hot air is less dense than cold air, hence the smoke rises.

Note: this is same well established technology that enables hot air balloons to fly.
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Old 18th April 2019, 11:18 AM   #348
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Originally Posted by Doubt View Post
Test questions for our thread starter to calibrate what we are dealing with.

Earth shape. Flat, round or other?
Is space real?
When we see the ISS passing overhead, what are we seeing?
Why are all developed countries lying about the reality of space flight?
Why are physicists and engineers lying about space flight?
If communication satellites are not real, what are all those satellite dishes pointed at?
None of my questions were answered yet.
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Old 18th April 2019, 11:21 AM   #349
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Originally Posted by dann View Post
That's a good question. Since it doesn't have anything to 'push' against, my guess is that Gingervytes will say no.
I already proved that here at around 5:45 https://www.youtube.com/watch?v=AubIFUsq7Ss&app=desktop
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Old 18th April 2019, 11:26 AM   #350
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Originally Posted by Gingervytes View Post
I already proved that here at around 5:45 https://www.youtube.com/watch?v=AubIFUsq7Ss&app=desktop
Youtube videos do not "prove" anything. Never have, never will. At best they can provide evidence for a principle or action that you will immediately not understand.
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Old 18th April 2019, 11:35 AM   #351
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Originally Posted by JayUtah View Post
So in a rocket thrust chamber, is there a difference in ambient pressure between the top (injector end) and the bottom (the nozzle throat)?
Or more accurately, let's imagine a sealed cylindrical container in a vacuum, in the absence of gravity. In this container has been placed a small amount of propellant that will magically spontaneously ignite after a time. The container is otherwise a vacuum. The propellant ignites, creating a mixture of gas, liquids, and solids. We have made the cylinder from a material robust enough to completely contain the effects of this combustion without leakage.

If the gas has any static pressure whatsoever, the difference in pressure between the interior of the cylinder and the ambient vacuum exerts mechanical force on the walls of the cylinder. The cylinder responds by incurring stress and deforming, even if that's only by an unnoticed amount. The tensile properties of any solid material confirm that in the absence of fracture, stress is transmitted from one part of the cylinder to another.

The question is in what direction these forces act? Consider a slice of the cylindrical wall. At each point, the gas pressure acts in the direction normal to the wall as defined at that point. Mechanically this has two important effects. First, all the points on the perimeter have a vector sum of zero. An equal pressure operating along each of those vectors has a vector sum of zero. The net force reckoned this way is zero, but it is a sum of actual non-zero vectors acting in the plane through which we took our slice. Second, the material of the cylinder is pushed outward uniformly along the perimeter, resulting in stress through the wall material. If the force were to exceed the tensile strength of the material, it would fracture along a line whose direction we could predict to be at right angles to the vectors of stress.

If we took our slice adjacent to the circular endcaps, part of the stress would be transmitted to the cap and produce a stress in it acting collectively in a way that wants the cap to have a greater diameter. (This is not the only stress the cap must withstand; read on.) We could predict the fracture line there too, knowing what forces are present and how the material responds.

We mention stresses and possible fracture to illustrate that the cylinder walls and the contained gas are mechanically coupled. The tensile properties of the cylinder and the gas properties of the gas reach a mechanical equilibrium that is a predictable result of known mechanical interaction. Gas exerts pressure either statically or as the result of fluid flow, and maintains pressure when mechanically constrained. Solids resist deformation when stressed.

Now consider the endcaps. In what direction does the gas exert pressure? As before, in the normal direction at each point where the gas applies. Except here the endcaps are planar. One endcap receives a force in the direction away from the center of the cylinder, of a magnitude equal to the unit gas pressure multiplied by the surface area of the cap. The cap responds to the pressure again by deformation, which may be miniscule and unnoticeable. But more importantly, it also responds by wanting to separate from the cylinder wall at the edge between the cap and the wall. The tensile effect there is that the right-angle joint between the wall material and the cap material is being stressed in a direction parallel to the cylinder axis.

The opposite endcap receives the same attention, but in the opposite direction. Thus the net force resulting from gas pressure is again zero, but for geometrically different reasons than apply to the cylinder wall. There you had a uniform pressure acting against the interior of a circle equally in all places. Here you have two parallel planes that are mechanically coupled by being attached to opposite ends of the same tube, and against each of which a force is acting in opposite directions with equal force. The vector sum here is zero: F and -F.

Also we have a new stress mode. If you envision the cylinder laying sideways, the left endcap is trying very hard to go to the left, pressed in that direction by the force of gas inside. The right endcap is trying equally hard to go to the right. The strain that results from this tug-of-war manifests itself as a tendency for the tube to elongate.

All this occurs because the system is responding to the effect of pressure versus and ambient background. If the ambient pressure were the same as the pressure of the exhaust from the spent propellant, there would be no net forces across the cylinder walls, no stress, and no danger of yield or rupture from gas pressure. The degree of mechanical responses and effects increase in proportion to the difference in pressure across the chamber walls.

Now imagine I have a button which, when pressed, causes the left endcap simply to cease to exist. I press it, and let's freeze time at that very instant. What can we say about the system now?

Ignore that the gas will later begin to expand into the newly-exposed vacuum to the left. We've frozen the system at Time 0. The left endcap is no longer there, and therefore no longer receiving any mechanical force from the pressure of the gas against it. More importantly, it's no longer transmitting that force to the cylinder wall that it is no longer connected to.

But the right endcap still is. The gas is still all in place, and the gas pressure is still acting against the right endcap. And that endcap is still transmitting tension -- i.e., pulling on -- the right edge of the tube. There is no balancing force on the left edge, so the tube wall now reacts differently. It doesn't want to elongate anymore, in response to opposing equal forces. The only force now acting parallel to the cylinder axis is the force applied by the right endcap.

We implied at the beginning that the cylinder was freely positioned in its environment, i.e. not connected to anything. If a force is applied to a stationary object preferentially in one direction, what do the laws of motion say will happen? Acceleration, of course. We would divide the force of the gas pressure against the right end cap by the mass of the cylinder, and from this we could accurately predict the momentary acceleration at that precise instant. (Momentary acceleration and other such values were an important innovation from Sir Isaac, and the reason he had to invent calculus to make everything work.)

The situation with the tube wall hasn't changed. The "contained" gas is still acting uniformly against the cylinder walls with zero net force. Our magic button changed only the geometry of the end caps.

Now advance the clock one microsecond. Some of the gas has escaped, but not all of it. Ignoring viscous flow and temperature effects for now, let's say that half the original gas mass is still present in the cylinder, and half of it escaped into the vacuum. It's gone, irrelevant. The half of the gas still remaining in what remains of the cylinder is still exerting pressure against the tube walls and against the remaining endcap -- but obviously only half as much as at Time Zero. We stipulate that to accommodate the escaped gas, the remnant has repositioned itself to be uniformly distributed.

We now have a finite, non-zero amount of time over which a force has acted continuously in the unbalanced way we described above at Time Zero. At Time 0 the instantaneous acceleration was endcap-pressure divided by cylinder mass. At T+1μs, instantaneous acceleration is half the original endcap pressure divided by cylinder mass. Pressure has been non-zero during that time, and therefore so has acceleration. If we have non-zero acceleration over non-zero time on a free body, at this point there must have occurred a change in velocity.

Notice that we haven't considered in the least what happened to the gas that left, or speculated in any way what it might have "pushed against." That's because that's not the pressure gradient we care about. The pressure gradient we care about is that across the endcap that remains. That's what's producing motive force. If I have a formulation that results in motion and which doesn't incorporate any "push-off" effect, I have refuted the notion that such an effect is needed.

At a certain point in this formulation, of course, all the gas will have left the cylinder at one rate or another, and no more unbalanced force will be applied against the inside of the right endcap. But given the specifics of the gas properties and the cylinder, we can accurately compute how much acceleration was imparted to the cylinder over the time in which a portion of the gas was still present and still exerting static pressure on the various parts of the cylinder.

Now for more magic, pretend that we have an apparatus that will cause more propellants magically to appear and combust inside the cylinder, just enough to replace in one microsecond the amount that escapes out the left in that same microsecond. If the lead time (to allow for the time combustion takes to occur) is carefully calibrated, I should be able to maintain a constant static pressure inside the cylinder, and therefore a constant pressure on the left endcap, and therefore a constant force to apply to acceleration.

And that would be a rocket.

Last edited by JayUtah; 18th April 2019 at 11:48 AM.
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Old 18th April 2019, 11:36 AM   #352
JayUtah
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Originally Posted by Gingervytes View Post
I already proved that here at around 5:45 https://www.youtube.com/watch?v=AubIFUsq7Ss&app=desktop
No, you keep referring back to the same video despite numerous refutations and corrections. Pointing your finger with increasing urgency at the same refuted evidence suggests you really don't understand the evidence by yourself, but are rather hoping that video does your talking for you and that you don't have to answer any questions.
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Old 18th April 2019, 11:41 AM   #353
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Originally Posted by Crossbow View Post
The reason why the smoke moves up is because hot air is less dense than cold air, hence the smoke rises.
Right, buoyancy. Smoke does not rise. Smoke is a solid aerosol entrained in a column of heated air. In a perfectly quiescent environment, smoke will fall to the ground just as effectively as dust, or a handful of marbles.

In my other life as a bartender, I sometimes make "smoked" drinks. A substantial amount of smoke is blown into a carafe and the drink swirled briefly in it to acquire the taste imparted by the smoke particles. Afterwards, I usually cap the carafe and set it aside. It's interesting to watch the smoke settle over a few hours and finally form a residue on the bottom of the carafe.

Buoyancy is mostly a local effect, and depends on gravity or some other force that acts preferentially on materials reckoned by volume.
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Old 18th April 2019, 11:46 AM   #354
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Originally Posted by JayUtah View Post
Right, buoyancy. Smoke does not rise. Smoke is a solid aerosol entrained in a column of heated air. In a perfectly quiescent environment, smoke will fall to the ground just as effectively as dust, or a handful of marbles.

In my other life as a bartender, I sometimes make "smoked" drinks. A substantial amount of smoke is blown into a carafe and the drink swirled briefly in it to acquire the taste imparted by the smoke particles. Afterwards, I usually cap the carafe and set it aside. It's interesting to watch the smoke settle over a few hours and finally form a residue on the bottom of the carafe.

Buoyancy is mostly a local effect, and depends on gravity or some other force that acts preferentially on materials reckoned by volume.
Aka soot.
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Old 18th April 2019, 11:47 AM   #355
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Originally Posted by dann View Post
That's a good question. Since it doesn't have anything to 'push' against, my guess is that Gingervytes will say no.
That seems consistent, but I hate to make assumptions on other people's behalf. His ideas don't really match with my own, so I'm not sure what his theory predicts when it comes to balloons.
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Old 18th April 2019, 11:55 AM   #356
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Originally Posted by JayUtah View Post
No, you keep referring back to the same video despite numerous refutations and corrections. Pointing your finger with increasing urgency at the same refuted evidence suggests you really don't understand the evidence by yourself, but are rather hoping that video does your talking for you and that you don't have to answer any questions.
We're taking his security blanket and tossing it. He can't handle that.
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Old 18th April 2019, 12:02 PM   #357
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Originally Posted by Gingervytes View Post
Do you have a simple experiment to show what you say is true. I have already shown that there is no equal and opposite force from gas movement due to pressure gradient force. Now it is your turn provide evidence
No, sorry. The burden of proof is yours, and you haven't shown a thing. You have just demonstrated ignorance.

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Old 18th April 2019, 12:02 PM   #358
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Originally Posted by Steve View Post
Youtube videos do not "prove" anything. Never have, never will. At best they can provide evidence for a principle or action that you will immediately not understand.
He doesn't seem to grasp that a video he finds on YouTube may be wrong. This is a product of our times, where it takes almost no effort to reach a worldwide audience. Back in the day, if you wanted to produce widely-distributed film, you had to convince someone who had the comparatively rare apparatus for making films, and someone else with the infrastructure for distribution, that your film was worth their expense and effort. That tended to weed out a lot of stuff. The gatekeeper criteria required many people to approve, agree to take a risk, or be suitably mollified.

Nowadays anyone can make a video in an afternoon and publish it for free to the civilized world. There are no longer any effective gatekeeper criteria and therefore no gravitas in there simply existing a video that says a thing.

In this case we've shown how the video is based on incorrect premises, incorrect models, and incorrect interpretation of results. Gingervytes is unable to address any of that, but wrongly claims he has. He simply points again and again to the video and tells us that by such an indication he has proved his point. Reasserting the refuted proposition does not negate the refutation. It's not an authoritative source just because it's a video that exists and can be viewed by anyone.
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Old 18th April 2019, 12:03 PM   #359
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If you pop a balloon in a vacuum, the gas that was inside it will expand equally in all directions. If another balloon is beside the one that is popped, it will be pushed away from where the first balloon popped.

Replace the second balloon with a bowl that is wrapped around the first balloon. Pop the balloon and the bowl will be pushed away.

You have just created a really inefficient rocket motor that obviously works even in a vacuum.

You can make it more efficient by converting the bowl into a combustion chamber that wraps almost completely around the source of the expanding gas and replacing the opening of the bowl with a nozzle which does a better job of accelerating the gas in one direction.

The above is the kind of analogy that even school kids have little trouble understanding.

And they also understand that the earth is spherical which is why rockets launched into orbit appear to curve downward some time after launch.

Last edited by jadebox; 18th April 2019 at 12:04 PM.
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Old 18th April 2019, 12:03 PM   #360
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Originally Posted by Steve View Post
Aka soot.
Well, that certainly takes the romance out of it.
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