[somerled]

Combustion will not occur in a vacuum .

Expanding gas in a vacuum does no work.

Newton did not say that momentum is conserved .

There is no "explosive force of combustion" - flowery language but not scientific. A fuel burn is an exothermic chemical reaction producing thermal energy which is not a force .

[AATW]

Combustion will not occur in a vacuum.

You're going to have to tell hypergolic fuels that.

Newton did not say that momentum is conserved

It's a consequence of his 3rd law

https://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle

There is no "explosive force of combustion" - flowery language but not scientific. A fuel burn is an exothermic chemical reaction producing thermal energy which is not a force.

Call it what you like. It expels gas at high velocity out of the rocket. The gas has mass.
Momentum = mass x velocity.
Momentum is conserved.
Rockets work, regardless of the medium they're operating in.

[iCare]

Combustion will not occur in a vacuum.

I'm still waiting for a valid explanation, why this should be the case.
When all required elements for fire/combustion are present (heat, fuel, and an oxidizing agent) are present, combustion will occur.

Expanding gas in a vacuum does no work.

Gas freely expanding into a vacuum (as described by Joule's Law) does not "work".
Gas being expelled "with force" does "work". No conflict with Joule's Law.

Imagine dropping a bouncing ball in a ideal environment (no friction, etc.); just let it go, no force applied - it will return to the same height. ("No work done" ... the energy at the beginning is equal to the energy at the end.)
Now push that ball down; force applied - it will return to the same height plus the additional height equivalent to the energy you provided by pushing it down.
This is a simile; it's not to be taken literally and an it is not perfect. It does however illustrate the point.

There is no "explosive force of combustion" - flowery language but not scientific. A fuel burn is an exothermic chemical reaction producing thermal energy which is not a force .

As repeatedly stated, burning fuel does not only produce heat.
And while that thermal energy may not be a force by itself, it can create force, e.g. by heating gas (e.g. the gas created together with heat) and thereby pressure, which is a force.
That is the basic principle of internal combustion engines. Like Wikipedia or not, but it's described nicely there:  https://en.wikipedia.org/wiki/Internal_combustion_engine
"An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is applied typically to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into useful work."

iC

[somerled]

Your gonna have show hyperbollix in action in a vacuum.

Newton's third law states nothing about conservation of momentum . It's about forces , active and reactive.

All laws of physics are derived from repeatable scientific experiment - the none Newton "law of conservation of momentum " is not derived from experiment but merely derived by shifting meaningless symbols as shown in your link .

This "law " may relate to rockets in a pressurised environment but then It's superfluous since the real Newton's laws cover that

The fact is in a vacuum there is no force produced - covered by the real laws derived from Joules real experiment , so the first line of derivation of this "law" of conservation of momentum
            F1 = -F2 is a complete fabrication under vacuum since it would violate Joules law . It assumes forces where none are produced .

You could of course show the experiment that this crap is derived from but you won't find it . This very very important psuedo law is very important to keep up the pretence of the rocket to the moon rubbish .

[iCare]

All laws of physics are derived from repeatable scientific experiment

covered by the real laws derived from Joules real experiment

I have said so before, I say so again:
Joule's experiment specifically requires constant temperature and a fixed amount of gas.
Both is not the case for rocket engines; Joules's experiment ist different from what creates thrust in a rocket.
=> Joule's Law is correct, validly derived from experiments. Your application of it is not, as you do not stay within the requirements set forth by Joule's experiment.
Or can you prove (by a repeatable scientific experiment?) that it is also true for increasing temperature and/or increasing amount of gas?

iC

[totallackey]

All laws of physics are derived from repeatable scientific experiment

covered by the real laws derived from Joules real experiment

I have said so before, I say so again:
Joule's experiment specifically requires constant temperature and a fixed amount of gas.

As if a rocket doesn't have a fixed amount of gas available...

Both is not the case for rocket engines; Joules's experiment ist different from what creates thrust in a rocket.
=> Joule's Law is correct, validly derived from experiments. Your application of it is not, as you do not stay within the requirements set forth by Joule's experiment.
Or can you prove (by a repeatable scientific experiment?) that it is also true for increasing temperature and/or increasing amount of gas?

iC

Yes.

All these videos here show all types of rockets, placed in an environment close to that of a vacuum,and they fail to work.

The reason they fail to work is Joules Law.

Now, back to how jets move...you never answered the question.

[iCare]

As if a rocket doesn't have a fixed amount of gas available...

I would think it obvious from watching any rocket, that the amount of gas increases.
Take, as example, a simply rocket for fireworks. Before igniting it, there is only the (solid) fuel and little to no gas.
After igniting the fuel, a large amount of gas (that obviously wasn't there before) is being expelled.

All these videos here show all types of rockets, placed in an environment close to that of a vacuum,and they fail to work.
The reason they fail to work is Joules Law.

I don't recall a video, where the rockets actually failed. Do you have a specific one in mind, we could look at in detail?
It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Now, back to how jets move...you never answered the question.

Not much to answer there.
Burning fuel creates gas and heat. => pressure => mass expelled => plane accelerates the other way.
The process is of course more complex and depending on the specific type of jet engine, there will be some difference in how that is achieved.

iC

[somerled]

All laws of physics are derived from repeatable scientific experiment

covered by the real laws derived from Joules real experiment

I have said so before, I say so again:
Joule's experiment specifically requires constant temperature and a fixed amount of gas.
Both is not the case for rocket engines; Joules's experiment ist different from what creates thrust in a rocket.
=> Joule's Law is correct, validly derived from experiments. Your application of it is not, as you do not stay within the requirements set forth by Joule's experiment.
Or can you prove (by a repeatable scientific experiment?) that it is also true for increasing temperature and/or increasing amount of gas?

iC

You really struggle with laws of physics  . Laws of physics relate to reality .
Newtons laws relate to where ever and whenever forces are involved and changes in motion occur .

According to your sophistry Joules law only applies to his experiment .  Applies to vacuum at all times . That's why it's a law.

Why don't you look at the Boyle's law , Charles law , Gay-Lussac's Law . Look at the relationship between temperature and pressure and this relationships effect on chemical reactions. You'll realise then why chemical reactions cant sustain themselves in a vacuum .

Why don't you provide a defense of the idiotically named "law of conservation of momentum" . Laws are derived from repeatable experiment not derived from assumption .

[AATW]

The fact is in a vacuum there is no force produced

When a rocket fires gas is propelled out of the end of the engine at high velocity, yes?
In order to reach that high velocity they must have been accelerated to it.
So for your next trick could you please explain how that happened without a force being applied?
F = ma

[iCare]

Newtons laws relate to where ever and whenever forces are involved and changes in motion occur .

Exactly. Well known examples are combustion engines in general and rockets in specific.

According to your sophistry Joules law only applies to his experiment .  Applies to vacuum at all times . That's why it's a law.

Not only to his experiment, but only to situations, that are actually described by Joule's Law.
Joule's Law describes how a constant amount of gas, that is kept at a constant temperature freely expands from a compartment of a closed volume to the complete volume.
It does not describe, how an increasing amount of gas, that is being heated up, expands under pressure into a large, open volume.
I'm staying true to Jule's Law, while you use it out of context.
Neither sophistry nor struggling with laws of physics on my side of this discussion ...

Newton's Laws apply whenever forces are involved and changes in motion => regardless of vacuum or no vacuum.
So if Newton's Laws apply to rockets in an atmosphere (which they seem to do - rockets work in an atmosphere), they also apply to rockets in a vacuum.

Why don't you look at the Boyle's law , Charles law , Gay-Lussac's Law . Look at the relationship between temperature and pressure and this relationships effect on chemical reactions. You'll realise then why chemical reactions cant sustain themselves in a vacuum .

Boyle's law requires temperature and amount of gas to remain unchanged.
Charles law requires the pressure to be constant.
Gay-Lussac's Law requires the pressure to be constant.
=> None of that is the case for rockets.
Why would any of those laws prevent chemical reactions from sustaining themselves in a vacuum?

Why don't you provide a defense of the idiotically named "law of conservation of momentum" . Laws are derived from repeatable experiment not derived from assumption .

Why would I?
It's basically common sense, that when each force has an equivalent opposing force, the change to momentum those forces create, will also equivalent. => conservation of momentum.

iC

[totallackey]

As if a rocket doesn't have a fixed amount of gas available...

I would think it obvious from watching any rocket, that the amount of gas increases.

In space (supposedly a vacuum)...

The amount of gas available in the rocket is fixed and throttled.

The vacuum is supposedly endless.

Take, as example, a simply rocket for fireworks. Before igniting it, there is only the (solid) fuel and little to no gas.
After igniting the fuel, a large amount of gas (that obviously wasn't there before) is being expelled.

The gas involved in Joules wasn't available to the vacuum "before," either...

I don't recall a video, where the rockets actually failed. Do you have a specific one in mind, we could look at in detail?

Watch all of them.

They are all here...

They all failed to work initially.

It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Yes, it is.

Gas is being released into a vacuum.

The rockets do not move until there is adequate presence of pressure in the container.

Now, back to how jets move...you never answered the question.

Not much to answer there.
Burning fuel creates gas and heat. => pressure => mass expelled => plane accelerates the other way.
The process is of course more complex and depending on the specific type of jet engine, there will be some difference in how that is achieved.

iC

I think you left something out...

What do you think of this quote?

“After compression it was heated, augmented by additional burning fuel(reported in the press to be kerosene), and finally discharged from the aft vent in a monstrous jet of energy pushing against the atmosphere.”

[somerled]

There is no law of conservation of momentum , psuedoscientific waffle that's why you are not able to direct me to the experiment that proves the concept . Mainstream science tries to hide this math trickery within the natural laws of physics , specifically Newton's laws .

Perhaps you are confusing the natural , real ,measured by experiment , law of conservation of energy with that bullshoite .

These natural laws cover all scenarios within mans experience regarding rocket engine production of thrust in pressurised or vacuum environs.

Oh - nice post Totallackey

Rocket engines cannot produce thrust in a vacuum - Joules 2nd law of thermodynamics . A real natural law provided by scientific experiment.

[iCare]

The amount of gas available is fixed and throttled.

Yes, it is usually throttled.
That raises the question, how do you explain, that in free expansion, there is no throttle and what about the Joule–Thomson effect (describing the temperature change of a real gas when it is forced through a valve), if there were a throttle?

Take, as example, a simply rocket for fireworks. Before igniting it, there is only the (solid) fuel and little to no gas.
After igniting the fuel, a large amount of gas (that obviously wasn't there before) is being expelled.

So how can the amount of gas be fixed?
The total volume of gas created by the chemical reaction can be calculated, but the amount over time (start to and of burn) is not fixed - it is increasing.

The vacuum is supposedly endless.

Supposedly ist is.
As explained before, this is one reason for Joule's Law not being applicable:
P_start*V_start=P_end*V_end will not work very well for V_end=∞.

They all failed to work initially.

Initially.
It is pretty normal for experiments to fail initially, e.g. due to mistakes in setup.
If they can be made to work reproducible, that's what counts.

It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Yes, it is.
Gas is being released into a vacuum.

No, it isn't as "releasing gas into a vacuum" is not the only requirement of Joule's Law of Free Expansion.

The rockets do not move until there is adequate presence of pressure in the container.

Indeed, they do not move until they are started.
When the fuel burns, it creates hot gas, pressure rises, rocket starts moving.
Doesn't matter, if there's a vacuum or not.

I think you left something out...
What do you think of this quote?
“After compression it was heated, augmented by additional burning fuel(reported in the press to be kerosene), and finally discharged from the aft vent in a monstrous jet of energy pushing against the atmosphere.”

I think, it sounds rather colloquial (in contrast to scientific), so I can't really tell if this is a scientifically audited and verified statement or just a simplified description for a general audience.
Regardless ... so what?
If there is an atmosphere, the gas expelled from a jet engine or a rocket will obviously push against it.
The thrust, however, is not created by "pushing against the atmosphere", but by expelling the gas.
I didn't mention the exhausted gas pushing against the atmosphere, because it is not what creates thrust.

iC

[totallackey]

The amount of gas available is fixed and throttled.

Yes, it is usually throttled.
That raises the question, how do you explain, that in free expansion, there is no throttle and what about the Joule–Thomson effect (describing the temperature change of a real gas when it is forced through a valve), if there were a throttle?

Pressure, whether or not it is throttled, is fixed at a rate by the type of gas.

Take, as example, a simply rocket for fireworks. Before igniting it, there is only the (solid) fuel and little to no gas.
After igniting the fuel, a large amount of gas (that obviously wasn't there before) is being expelled.

So how can the amount of gas be fixed?
The total volume of gas created by the chemical reaction can be calculated, but the amount over time (start to and of burn) is not fixed - it is increasing.[/quote]
Holy cow...

It is fixed by the very definition of the word - THROTTLE!

The vacuum is supposedly endless.

Supposedly ist is.
As explained before, this is one reason for Joule's Law not being applicable:
P_start*V_start=P_end*V_end will not work very well for V_end=∞.

LOL!

All the more reason it will work!

They all failed to work initially.

Initially.
It is pretty normal for experiments to fail initially, e.g. due to mistakes in setup.
If they can be made to work reproducible, that's what counts.

They are all reproducible and they all definitively show and demonstrate for the whole wide world to see...

ROCKETS DO NOT WORK IN A VACUUM!

It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Yes, it is.
Gas is being released into a vacuum.

No, it isn't as "releasing gas into a vacuum" is not the only requirement of Joule's Law of Free Expansion.

When it comes to a container of gas being opened up to (or within) the confines of a vacuum, then yes it does.

The rockets do not move until there is adequate presence of pressure in the container.

Indeed, they do not move until they are started.
When the fuel burns, it creates hot gas, pressure rises, rocket starts moving.
Doesn't matter, if there's a vacuum or not.

Yes, it does, as the claim made by me and others is: ROCKETS DO NOT WORK IN A VACUUM!

The rockets in these videos do not work until an environment OTHER THAN A VACUUM is present.

I think you left something out...
What do you think of this quote?
“After compression it was heated, augmented by additional burning fuel(reported in the press to be kerosene), and finally discharged from the aft vent in a monstrous jet of energy pushing against the atmosphere.”

I think, it sounds rather colloquial (in contrast to scientific), so I can't really tell if this is a scientifically audited and verified statement or just a simplified description for a general audience.
Regardless ... so what?
If there is an atmosphere, the gas expelled from a jet engine or a rocket will obviously push against it.
The thrust, however, is not created by "pushing against the atmosphere", but by expelling the gas.
I didn't mention the exhausted gas pushing against the atmosphere, because it is not what creates thrust.

iC

Well, it does claim the exact opposite of what you just wrote:"The thrust, however, is not created by "pushing against the atmosphere", but by expelling the gas."

The article is clear: "This backward push produced the equivalent in forward thrust."

And it is POPULAR SCIENCE, a respected periodical not known to lie to its audience, I think I would trust this more than you.

[AATW]

There is no law of conservation of momentum

You're going to have to tell physics that

One of the most powerful laws in physics is the law of momentum conservation. The law of momentum conservation can be stated as follows.

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

Source:
https://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle

Just shouting "isn't, isn't, isn't" really isn't a rebuttal, you know. The link above outlines some experiments which demonstrate the principle.

[iCare]

Pressure, whether or not it is throttled, is fixed at a rate by the type of gas.

What do you mean by that?
Pressure depends on several variables, not just on the type of gas.

It is fixed by the very definition of the word - THROTTLE!

We are clearly talking about different things.
"A throttle is the mechanism by which flow is managed by constriction or obstruction."

• It has nothing to do with the amount of gas it throttles.
• It manages flow, i.e. it is not fixed.

P_start*V_start=P_end*V_end will not work very well for V_end=∞.

LOL!
All the more reason it will work!

Care to explain, why that would be?

ROCKETS DO NOT WORK IN A VACUUM!

Capitals only make it "louder", not truer.

It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Yes, it is.
Gas is being released into a vacuum.

No, it isn't as "releasing gas into a vacuum" is not the only requirement of Joule's Law of Free Expansion.

When it comes to a container of gas being opened up to (or within) the confines of a vacuum, then yes it does.

Then explain, why you can disregard the requirements for constant temperature and constant amount of gas?

Well, it does claim the exact opposite of what you just wrote:"The thrust, however, is not created by "pushing against the atmosphere", but by expelling the gas."
The article is clear: "This backward push produced the equivalent in forward thrust."
And it is POPULAR SCIENCE, a respected periodical not known to lie to its audience, I think I would trust this more than you.

Well strictly speaking, it does not say "This backward push against the atmosphere produced the equivalent in forward thrust."
But it does sound like they actually meant it the way, you understand it.
I can't tell and I do not know, what they based their conclusions on.

I prefer to believe currently respected science (=> rockets do work in a vacuum) rather than an historic periodical.
It is the backward push exerted on the exhausted gas, not on the atmosphere that produces the equivalent in forward thrust (=>Newton's Laws).

iC

[totallackey]

Pressure, whether or not it is throttled, is fixed at a rate by the type of gas.

What do you mean by that?
Pressure depends on several variables, not just on the type of gas.

It is fixed by the type of gas.

Whether that gas is going through a throttle or not.

All gas has a specified pressure achieved by the size of the container and by the type of throttling.

And it is fixed.

It is fixed by the very definition of the word - THROTTLE!

We are clearly talking about different things.
"A throttle is the mechanism by which flow is managed by constriction or obstruction."

• It has nothing to do with the amount of gas it throttles.
• It manages flow, i.e. it is not fixed.

It is by the nature of the gas that the throttle is throttling.

And a throttle is FIXED at a certain amount.

P_start*V_start=P_end*V_end will not work very well for V_end=∞.

LOL!
All the more reason it will work!

Care to explain, why that would be?

Yes.

When the vacuum is supposedly infinite, there is no chance for the gas to equalize the pressure.

ROCKETS DO NOT WORK IN A VACUUM!

Capitals only make it "louder", not truer.

My intent was not to make it louder.

It is an exclamation based on the physical evidence placed here by the proponents of rockets working in a vacuum, that distinctly and definitively show OTHERWISE.

It cannot be Joule's Law, when the requirements for Joule's Law to apply are not met.

Yes, it is.
Gas is being released into a vacuum.

No, it isn't as "releasing gas into a vacuum" is not the only requirement of Joule's Law of Free Expansion.

When it comes to a container of gas being opened up to (or within) the confines of a vacuum, then yes it does.

Then explain, why you can disregard the requirements for constant temperature and constant amount of gas?

1) Who said there is a requirement for constant temperature?
2) The amount of gas released from a rocket is constant (i.e., the throttle).

Well, it does claim the exact opposite of what you just wrote:"The thrust, however, is not created by "pushing against the atmosphere", but by expelling the gas."
The article is clear: "This backward push produced the equivalent in forward thrust."
And it is POPULAR SCIENCE, a respected periodical not known to lie to its audience, I think I would trust this more than you.

Well strictly speaking, it does not say "This backward push against the atmosphere produced the equivalent in forward thrust."
But it does sound like they actually meant it the way, you understand it.
I can't tell and I do not know, what they based their conclusions on.

I can tell...

They base their conclusions on SCIENCE!

I prefer to believe currently respected science (=> rockets do work in a vacuum) rather than an historic periodical.
It is the backward push exerted on the exhausted gas, not on the atmosphere that produces the equivalent in forward thrust (=>Newton's Laws).

iC

You have no "currently respected science."

You have a bunch of loonies from Quora writing crap...

[somerled]

There is no law of conservation of momentum

You're going to have to tell physics that

One of the most powerful laws in physics is the law of momentum conservation. The law of momentum conservation can be stated as follows.

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

Source:
https://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle

Just shouting "isn't, isn't, isn't" really isn't a rebuttal, you know. The link above outlines some experiments which demonstrate the principle.

It is not a law, it is a mathematical theoretic concept with no basis in reality and based in theory only . Real physicists know that. Your link assumes force when the laws of physics state there is non in a vacuum .

Taken from wiki https://en.wikipedia.org/wiki/Momentum

"Symmetry and conservation
Conservation of momentum is a mathematical consequence of the homogeneity (shift symmetry) of space (position in space is the canonical conjugate quantity to momentum). That is, conservation of momentum is a consequence of the fact that the laws of physics do not depend on position; this is a special case of Noether's theorem.[31] "

The natural real laws apply to reality and imaginary laws apply only to imaginary scenarios ( although one could always imagine another scenario where the first imaginary law could be replaced by another imaginary law theoretical schmience at it's best ). Noether's theorem is erm theory .

You could of course provide the real experiment which allows you spout your usual unsubstantiated bs .

[iCare]

All gas has a specified pressure achieved by the size of the container and by the type of throttling.
And it is fixed.

If that gas is heated/cooled, the pressure will change.
If the size of the container is changed, the pressure will change.
If the amount of gas is changed, the pressure will change.
A throttle would indirectly change the amount of gas by throttling the inflow or outflow of gas.
How do you conclude, that all gas would have a specified and unchangeable pressure?

And a throttle is FIXED at a certain amount.

A throttle is most certainly not fixed at a certain amount; the very idea of a throttle is to variably restrain the flow of e.g. fuel.
At least that is the throttle I know from planes, cars, motrocycles, ...
Do you refer to a different kind of throttle?

When the vacuum is supposedly infinite, there is no chance for the gas to equalize the pressure.

You really should take a closer look at Joule's experiment on Free Expansion.
It specifically compares at a stable initial state and a stable end state.
If the pressure cannot equalize, there will be no end state.
And why would equalization of pressure be relevant in any case? It is not a significant factor for a rocket working in a vacuum.

Then explain, why you can disregard the requirements for constant temperature and constant amount of gas?

1) Who said there is a requirement for constant temperature?
2) The amount of gas released from a rocket is constant (i.e., the throttle).

• Joule's Law/Experiment. His conclusion was, as the temperature does not change, no work is done. So if the temperature changes, it is not Joules Law of Free Expansion. 
• No, it is not. The whole idea of a throttle is to control the thrust of jet engines and rockets, see above.

And it is POPULAR SCIENCE, a respected periodical not known to lie to its audience, I think I would trust this more than you.

Well strictly speaking, it does not say "This backward push against the atmosphere produced the equivalent in forward thrust."
But it does sound like they actually meant it the way, you understand it.
I can't tell and I do not know, what they based their conclusions on.

I can tell...
They base their conclusions on SCIENCE!

So how can you tell?
Is there any verifiable scientific description how they reached their conclusions?
In the article there isn't, it's just a pretty generic description that obviously is more focused on giving a general idea than specifics. (Which is not a bad thing at all.)
Are you aware, that science itself is not static and that laws/theories/... have often been corrected, specified in more detail or improved by later studies/experiments?

You have no "currently respected science."
You have a bunch of loonies from Quora writing crap...

Actually I have Newton and the established laws of physics, chemistry and thermodynamics.
Applied in a scientifically correct way, they prove that rockets work in a vacuum.

iC

[somerled]

"Actually I have Newton and the established laws of physics, chemistry and thermodynamics.
Applied in a scientifically correct way, they prove that rockets work in a vacuum.

iC"

No you haven't, which is why Nasa and it's apologists have to use the imaginary "law of conservation of momentum" despite having no scientific evidence which would allow it to be classed as such.