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Old 20th April 2019, 01:55 AM   #481
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So we know that smoke rises, as it's attracted to low pressure and there's lots of low pressure at high altitude. The rocket generates a huge cloud of smoke and carefully balances on top of it, thereby hitching a ride to the upper atmosphere before the smoke disperses and it falls back down and into the ocean. Simple, really. I don't know why everyone makes it sound so complicated. I mean, its not brain surgery.
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Old 20th April 2019, 02:05 AM   #482
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I think the o/p has achieved his objective - about 20 members of the NWO have been kept busy arguing against him and getting behind with their real work. My chemtrail project is way behind schedule.
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Old 20th April 2019, 02:14 AM   #483
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Jesus Freaking Christ.

For every action there is an equal and opposite reaction. No air required.

An ongoing explosion of fuel blasts out the nozzle. That is the action.
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Old 20th April 2019, 04:43 AM   #484
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Originally Posted by Gingervytes View Post
And in the case of a rocket. Pressure expands due to pressure gradient force and not because the rocket pushes it
Oh, a claim.

Please provide an example of pressure expanding. Any example. Even one.
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Old 20th April 2019, 05:16 AM   #485
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Originally Posted by phunk View Post
Ok let's go with your theory for one sec. Imagine a lot of gas released into the vacuum of space. It is unconstrained and expanding in all directions. If there were an object next to that cloud, would it be pushed even the slightest bit by the wind then the expanding cloud contacted it?
Yes. Gas does no work in a vacuum.
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Old 20th April 2019, 05:18 AM   #486
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Originally Posted by abaddon View Post
Oh, a claim.

Please provide an example of pressure expanding. Any example. Even one.
you clearly knew I meant to say gas expands, youíre just grasping at straws
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Old 20th April 2019, 05:28 AM   #487
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All right, here's the real sooper seekrit explanation we've all be trying to withhold.

Imagine a rocket in the vacuum of space. It's releasing exhaust gases. Into the vacuum of space.

As a result, the vacuum of space isn't a vacuum any more! It's now full of rocket exhaust. The rocket pushes off that to achieve thrust.

We don't like to admit that because we don't want environmentalists getting all up in our grill about "vacuum pollution" and marching outside launch facilities with signs saying "Save Our Space," "Avoid the Void," and "Keep Your Gases Out Of My Heavens."

So, please don't tell anyone, ok, Gingervytes?
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Old 20th April 2019, 05:37 AM   #488
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
Why not? Gas has mass, and if that mass is moving and meets another mass then their interaction is determined by Newtonian physics.
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Old 20th April 2019, 05:46 AM   #489
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Originally Posted by phunk View Post
Ok let's go with your theory for one sec. Imagine a lot of gas released into the vacuum of space. It is unconstrained and expanding in all directions. If there were an object next to that cloud, would it be pushed even the slightest bit by the wind then the expanding cloud contacted it?

Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.

What vacuum? After you release a lot of gas unconstrained in the vacuum of space, there's no longer a vacuum there. So now the gas can do work on the object.

Same with rockets. Have you noticed how the earliest space missions barely went beyond the atmosphere, and over time they've been able to go farther and farther? That's because they'e pushing against the gas that was released by earlier rockets.

You have to go out past Neptune's orbit to find a decent vacuum any more.
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Old 20th April 2019, 06:37 AM   #490
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
You do not know what you are talking about.
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Old 20th April 2019, 07:09 AM   #491
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Originally Posted by phunk View Post
Ok let's go with your theory for one sec. Imagine a lot of gas released into the vacuum of space. It is unconstrained and expanding in all directions. If there were an object next to that cloud, would it be pushed even the slightest bit by the wind then the expanding cloud contacted it?
Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
Which is it? Yes, the object is pushed slightly by the wind, or no, gas does no work?
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Old 20th April 2019, 07:32 AM   #492
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
If there's gas, then it isn't a vacuum.


Any thoughts on balloons? If you open the neck of an inflated balloon in the atmosphere, the balloon moves. What if you do the same thing in space?
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Old 20th April 2019, 07:47 AM   #493
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Originally Posted by Meadmaker View Post
If there's gas, then it isn't a vacuum.


Any thoughts on balloons? If you open the neck of an inflated balloon in the atmosphere, the balloon moves. What if you do the same thing in space?
Take a look at the experiment in this video with the balloon car. https://www.youtube.com/watch?v=AubIFUsq7Ss
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Old 20th April 2019, 07:56 AM   #494
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Originally Posted by Gingervytes View Post
Take a look at the experiment in this video with the balloon car. https://www.youtube.com/watch?v=AubIFUsq7Ss
Released by flatearthrevolution.com? Are you also a flat earther?

For other posters: flatearthrevolution.com is about 30% by weight expletives.
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Old 20th April 2019, 07:56 AM   #495
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
There's either a gas or there's a vacuum. Said another way, the potential to do pressure-and-volume work exists any time you have two volumes with differing pressures, P1 and P2. There is no magical law that forbids either P1 or P2 to be zero. You're operating under the premise that vacuum comprises some sacred condition under which the laws of physics suddenly behave differently.
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Old 20th April 2019, 07:58 AM   #496
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Originally Posted by Gingervytes View Post
you clearly knew I meant to say gas expands, youíre just grasping at straws
No. You have consistently misused terminology and misconceived important elementary concepts. There is no reason to believe your error in this case was merely having misspoken. You clearly want to be seen as some sort of expert in the behavior of fluids. Experts know how to use the right words. That's one of the ways we can tell they're experts.
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Old 20th April 2019, 08:00 AM   #497
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Originally Posted by Gingervytes View Post
Take a look at the experiment in this video with the balloon car. https://www.youtube.com/watch?v=AubIFUsq7Ss
No more videos. You have been given detailed explanations for how gas behaves and how motive effort arises. If you cannot respond to those explanations, it is very unlikely that you can tell whether a video made by someone else has correctly stated the problems and solutions.

Are you a flat-earther? Yes or no, please.
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Old 20th April 2019, 08:04 AM   #498
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Originally Posted by Gingervytes View Post
Take a look at the experiment in this video with the balloon car. https://www.youtube.com/watch?v=AubIFUsq7Ss

From the very silly youtube video:

"Additionally, free expansion of gas states that gas expanding into a vacuum does no work."

If you place a windmill in the tube connecting the chamber with gas with the chamber with a vacuum, you'll notice that "gas expanding into a vacuum" makes the windmill turn.
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Old 20th April 2019, 08:10 AM   #499
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Originally Posted by dann View Post
From the very silly youtube video:

"Additionally, free expansion of gas states that gas expanding into a vacuum does no work."
All the other tidbits of wisdom in his arguments have just been excerpts from the crank videos he's linked to. I don't see that his argument rises any higher than parroting the crap one can find on YouTube. His laughable responses to criticism and correction indicate he really has no intrinsic understanding. Once we get him beyond the point where repeating the sound bite du jour no longer works, he has nothing else.
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Old 20th April 2019, 08:12 AM   #500
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Originally Posted by JayUtah View Post
Are you a flat-earther? Yes or no, please.

The Youtube video advertises for FlatEarthRevolution.com.
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Old 20th April 2019, 08:14 AM   #501
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Originally Posted by dann View Post
The Youtube video advertises for FlatEarthRevolution.com.
That's what motivated my question. If that's the sort of source he's considering authoritative, then I want to know why.
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Old 20th April 2019, 08:15 AM   #502
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Originally Posted by Myriad View Post
You have to go out past Neptune's orbit to find a decent vacuum any more.
Which is why James Dyson is leaving the UK.
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Old 20th April 2019, 08:35 AM   #503
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We know that rockets don't work because Elton John only writes songs about fictional subjects. Also Princess Di is not real.
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Old 20th April 2019, 08:45 AM   #504
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If I'm in space and I throw a baseball it will impart motion to me. A rocket is just throwing a lot of really hot, really small baseballs out the back really fast. The nozzle corrects your throws to make sure they are really going straight back.
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Old 20th April 2019, 08:46 AM   #505
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Originally Posted by Gingervytes View Post
Take a look at the experiment in this video with the balloon car. https://www.youtube.com/watch?v=AubIFUsq7Ss
I certainly wasn't going to watch the whole video, but I did find a few seconds of balloon car footage.

I'm afraid I can't quite follow the implications of the video when it comes to answering the question about a balloon in space. You may have to walk me through it.

It seems like the video was implying that with the partial vacuum created by the vacuum cleaner meant there was less air to "push off" of, so the car moves slower. Did I get that right? And the implication is that if there is no air at all to push off of, it wouldn't move at all. Is that correct? I hate to put words in people's mouths, especially when I don't understand their overall perspective, so I just want to be sure. I'm going to proceed based on that assumption, that they are implying the balloon car wouldn't work in a total vacuum, because there is nothing to push against. If I'm wrong about what they (and you, by citing them) are saying, then this next part won't make much sense, but that's the way it goes.

(Aside: I asked about a toy balloon flying free, but the balloon car is a perfectly good example, and easier to understand, so in any future discussion, I think sticking with the balloon car is a good idea.)

Anyway, I have an alternative explanation for why the car slows down in the video, and I'd like to run it past you. I also have an experiment that I could propose to test it.

I believe that when the vacuum cleaner is working, it creates an area of low pressure behind the car. Since the car is still subject to atmospheric pressure in the front of the car, there is a force pushing toward the rear of the car due to the pressure gradient. Without the vacuum cleaner, the car, with the balloon neck release, accelerates forward, propelled by the air escaping from the balloon. With the vacuum cleaner, my theory is that the car experiences exactly the same force from the air in the balloon, but there is an additional force from atmospheric pressure in the front of the car. Therefore the car accelerates more slowly.

We could test this theory by equalizing the pressure in the front of the car. In other words, run a second vacuum cleaner at the front of the car. Now, there is still less atmosphere behind the car to "push off" of, but there is no pressure gradient from the front of the car to the back of the car. In the two vacuum case, your theory predicts that the car would move more slowly than with the "no vacuum" case. My theory, which is the one taught in physics classes around the world, predicts that in the two vacuum case, the car would move at the same speed as the no vacuum case.

Let me sum that up in the form of a question, to make sure I understand your theory. Suppose, in the youtube video you linked to, they had run a second experiment where there was a vacuum cleaner running in front of the car as well as one running behind it. How would the speed of the car compare to the case in which there was no vacuum cleaner at all?


(One more aside. Some cynics might point out that the reason the car moves more slowly in the experiment with the vacuum cleaner, is that the car is being sucked toward the vacuum cleaner, because, after all, that is what vacuum cleaners do. This "common sense" explanation is not entirely wrong, it just doesn't explain the source of the apparent sucking force. It's actually more of a blowing force acting on the front of the car.)

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Old 20th April 2019, 08:50 AM   #506
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Originally Posted by Meadmaker View Post
I believe that when the vacuum cleaner is working, it creates an area of low pressure behind the car. Since the car is still subject to atmospheric pressure in the front of the car, there is a force pushing toward the rear of the car due to the pressure gradient. Without the vacuum cleaner, the car, with the balloon neck release, accelerates forward, propelled by the air escaping from the balloon. With the vacuum cleaner, my theory is that the car experiences exactly the same force from the air in the balloon, but there is an additional force from atmospheric pressure in the front of the car. Therefore the car accelerates more slowly.

We could test this theory by equalizing the pressure in the front of the car. In other words, run a second vacuum cleaner at the front of the car. ...
Exactly. The video is a joke.
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Old 20th April 2019, 08:51 AM   #507
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Originally Posted by Meadmaker View Post
It seems like the video was implying that with the partial vacuum created by the vacuum cleaner...
And the resulting rearward flow. The car would have to fight that headwind. Videos made by people who have never had to work around jet engines.
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Old 20th April 2019, 08:52 AM   #508
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Originally Posted by Doubt View Post
We know that rockets don't work because Elton John only writes songs about fictional subjects.
Clearly "Candle In the Wind" contains a hidden message about the ability of gas to do work.
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Old 20th April 2019, 09:09 AM   #509
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Originally Posted by dann View Post
From the very silly youtube video:

"Additionally, free expansion of gas states that gas expanding into a vacuum does no work."

If you place a windmill in the tube connecting the chamber with gas with the chamber with a vacuum, you'll notice that "gas expanding into a vacuum" makes the windmill turn.
Actually, depending on how you read this, it's technically correct.

If you assume "free expansion" means "expanding with nothing impeding that expansion".

Unfortunately, that is not the case with a windmill, or inside a rocket's combustion chamber.
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Old 20th April 2019, 09:23 AM   #510
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Originally Posted by Lithrael View Post
Is it too late to point out that the reason why a gas wants to expand into a vacuum is because all of the particles of the gas are hitting each other and then bouncing further away from each other, and absolutely not because the vacuum is yoinking them in any way?
A memorable line from the old "Building Scientific Apparatus" book: "Vacuum doesn't suck"

It's true!
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Old 20th April 2019, 09:25 AM   #511
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The whole point of thermodynamic engines is to prevent the working fluid from expanding or flowing freely. Rather, you devise an apparatus in which the tendency to expand is captured and made to do work. A rocket thrust chamber does that preferentially in one direction. I suspect this fact is why our poster is so adamant about not answering the questions that ask about the direction of expansion.
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Old 20th April 2019, 09:27 AM   #512
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Originally Posted by dann View Post
From the very silly youtube video:

"Additionally, free expansion of gas states that gas expanding into a vacuum does no work."
But the directed "expansion" of gas out a nozzle is NOT a "free" expansion. so it's not clear what that has to do with anything involving rockets.
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Old 20th April 2019, 09:31 AM   #513
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Originally Posted by Hellbound View Post
Actually, depending on how you read this, it's technically correct.

If you assume "free expansion" means "expanding with nothing impeding that expansion".

Unfortunately, that is not the case with a windmill, or inside a rocket's combustion chamber.
This.


The rocket exhaust is not freely expanding. It has a constraint, the rocket itself, on one side and that is where the work happens.
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Old 20th April 2019, 09:47 AM   #514
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Originally Posted by pgwenthold View Post
But the directed "expansion" of gas out a nozzle is NOT a "free" expansion. so it's not clear what that has to do with anything involving rockets.
Very much not free. Let's not forget all the stuff earlier in the thread about the nozzles.
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Old 20th April 2019, 10:13 AM   #515
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
What is your evidence for this?

Why do steam turbines and triple expansion engines use a condenser on the exhaust to reduce pressure and produce a vacuum?

As a hint, it is the reason that marine steam engines both turbine and reciprocating are much more efficient than their railroad counterparts.

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Old 20th April 2019, 10:32 AM   #516
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
Gas in a vacuum is responsible for literally everything. Without it there would be no stars and therefore nothing that results from stellar activity including Earth, us, and our rockets.
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Old 20th April 2019, 11:35 AM   #517
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By coincidence, today I watched a video on this equation:


https://en.wikipedia.org/wiki/Tsiolk...ocket_equation

It relates the velocity of a rocket to the exhaust velocity and mass of the propellant and oxidizer. The video itself was part of a MOOC class taught at edx.org on space mission planning. Fascinating stuff. It is highly unlikely I will ever use this as part of a career. I'm a bit old to start working on spacecraft again. (I worked briefly in the Space and Communications group of Hughes Aircraft, many years ago, but only touched very, very, briefly on orbital analysis, and never on propulsion systems.) Nevertheless, it's fascinating. I've watched many, many, documentaries on space exploration, but to see the actual equations and calculations used, or even the simplified versions taught in the class, really makes me appreciate the effort that goes into making all this stuff work. Now that I know more about how the Space Shuttle went from orbit to landing I'm even more impressed that they could take that glider with the flight characteristics of a brick and manage to hit a runway that was halfway across the world, literally, from the point where they fired the engines so that they would end up in the right spot.


The professor of the course made that trip twice, personally, or so he says.


If the OP were correct, none of it would be possible, and Tsiolkovsky (whoever he was*, off to read the article after this) would not be worth studying.


ETA *An eccentric Russian math teacher who read a lot of science fiction, which basically in his time meant Jules Verne. Oh, he was also a brilliant man who developed a lot of the theoretical foundations for space flight, including the equation above. Note: He died in the Soviet Union, long before NASA ever came into existence


https://en.wikipedia.org/wiki/Konstantin_Tsiolkovsky.

Last edited by Meadmaker; 20th April 2019 at 11:46 AM.
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Old 20th April 2019, 12:53 PM   #518
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Originally Posted by Gingervytes View Post
Yes. Gas does no work in a vacuum.
You are yet another science denier mistaking "does no work in a vacuum" for "does not work in a vacuum".

I believe you are also mistaking "in a vacuum" for "on a vacuum".
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Old 20th April 2019, 01:10 PM   #519
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Originally Posted by Gingervytes View Post
Gas does no work in a vacuum.

For some reason Iím hearing this with a Scottish accent.
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Old 20th April 2019, 01:11 PM   #520
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Originally Posted by Gingervytes View Post
Gas does no work in a vacuum.

What if itís next to a rocket?
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