.....

Quote from: sceptimatic on November 23, 2012, 04:05:54 AM

That balloon experiment is simply expelling air against the atmosphere behind it, forcing the balloon forward, same with the balloon being on the car.

So that means a more robust substance behind the balloon should allow the balloon to move faster then, right? Let's put it in water then. Or even better, let's encase it in concrete and see how far it goes.

I think this is the best point against sceptimatics idea of the balloon experiment working because of earth atmosphere. Because all the atmosphere does is increase the resistance, so if according to him that is what makes it move, and that is why they would not work in space, a denser environment would mean more movement. But it doesn't.

What you don't seem to understand is rocket propulsion isn't like swimming. When you're swimming, you're fuel is the water around you, your thrust is pushing the water back. It's difficult and extremely inefficient. When a rocket goes, it's fuel is in the tank. It burns this fuel to create a more energetic thrust. By burning it, the mass/energy moves faster out of the nozzles than it would have just being pumped out. So the rocket goes in the opposite direction of the force.

What he does not understand is the complete Third Newton's Law of Motion. He has accepted this fact but still talks like he knew what he was saying when an experiment that is based on that law passes through his head.

I think he knows that we have answered every single question he has raised around this subject.

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Quote from: robertotrevor on November 23, 2012, 06:27:39 AM

Quote from: ThinkingMan on November 23, 2012, 05:47:06 AM

Quote from: sceptimatic on November 23, 2012, 04:05:54 AM

That balloon experiment is simply expelling air against the atmosphere behind it, forcing the balloon forward, same with the balloon being on the car.

So that means a more robust substance behind the balloon should allow the balloon to move faster then, right? Let's put it in water then. Or even better, let's encase it in concrete and see how far it goes.

I think this is the best point against sceptimatics idea of the balloon experiment working because of earth atmosphere. Because all the atmosphere does is increase the resistance, so if according to him that is what makes it move, and that is why they would not work in space, a denser environment would mean more movement. But it doesn't.

It's a very bad point .

Explain why you would move less on the water or any other denser environment, if according to you is the push against this density (air resistance) that makes movements like this possible in earth, while no density in space (vacuum) would mean no movement.

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

If you talk about weight, you are already taking gravity as a factor.

Quote from: sceptimatic on November 23, 2012, 08:42:56 AM

Explain why you would move less on the water or any other denser environment, if according to you is the push against this density (air resistance) that makes movements like this possible in earth, while no density in space (vacuum) would mean no movement.

I didn't mean it was a bad point as regards that, I meant it's a bad point to make as I'm not dealing with water or anything working better than anything else on Earth.

My argument is simply that the vacuum of space is( what we are told) a vacuum and a rocket will not work in the vacuum of the expanse of space.

I find it ironic how you repeat "how we have been told" so many times on your posts, but never understanding what "we have been told". Because vacuum is just that, nothing, no air, no density, there is no reason for things to magically stop working. That is something you added.
If air density was the factor that allowed movement in the experiment, you should move more increasing the density.

Don't be changing it now.

You and others said that it was mass and "not" gravity or air that caused the action/reaction.

I don't really know what you mean, but if we are talking about rockets , gravity is a factor to take in account because it makes it harder for the rocket to get into space, not helping it move (if that is what you meant)

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

Gravity is always a factor. We were explaining the fundamentals of the laws of motion. Gravity is not a factor in the third law of motion, but it is a factor on the whole scale, i.e. what I said before, an object in motion will continue in motion until another force acts on it.

Quote from: robertotrevor on November 23, 2012, 08:39:56 AM

Quote from: sceptimatic on November 23, 2012, 08:23:15 AM

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

If you talk about weight, you are already taking gravity as a factor.

Don't be changing it now.

You and others said that it was mass and "not" gravity or air that caused the action/reaction.

No one said gravity does not cause the action/reaction, and also, no one said it does. Because guess what, gravity has nothing to do with how a rocket works. The rocket has to fight gravity and air resistance to go anywhere, be it up in space or into your front window. Everything here on earth's surface has to fight gravity and air resistance. Why do you think airplanes are so streamline looking, as well as rockets? If they were cube shaped, it would be much more difficult to keep them aloft.

Now, mass and energy are factors in the action/reaction. Just mass and energy. That's it. You're either not reading everything we say and picking out select words to try and troll with, or you're simply not comprehending it at all.

Quote from: ThinkingMan on November 23, 2012, 09:02:25 AM

Quote from: sceptimatic on November 23, 2012, 08:23:15 AM

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

Gravity is always a factor. We were explaining the fundamentals of the laws of motion. Gravity is not a factor in the third law of motion, but it is a factor on the whole scale, i.e. what I said before, an object in motion will continue in motion until another force acts on it.

Quote from: sceptimatic on November 23, 2012, 08:44:49 AM

Quote from: robertotrevor on November 23, 2012, 08:39:56 AM

Quote from: sceptimatic on November 23, 2012, 08:23:15 AM

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

If you talk about weight, you are already taking gravity as a factor.

Don't be changing it now.

You and others said that it was mass and "not" gravity or air that caused the action/reaction.

No one said gravity does not cause the action/reaction, and also, no one said it does. Because guess what, gravity has nothing to do with how a rocket works. The rocket has to fight gravity and air resistance to go anywhere, be it up in space or into your front window. Everything here on earth's surface has to fight gravity and air resistance. Why do you think airplanes are so streamline looking, as well as rockets? If they were cube shaped, it would be much more difficult to keep them aloft.

Now, mass and energy are factors in the action/reaction. Just mass and energy. That's it. You're either not reading everything we say and picking out select words to try and troll with, or you're simply not comprehending it at all.

I'm not talking about a rocket overcoming gravity though, I was on about the medicine ball experiment and you saying gravity has nothing to do with it.

I'm talking about space and rockets. Not rockets overcoming Earth's gravity.

The medicine ball experiment is the same concept as a rocket. You're expelling a mass one way to move a mass another way.

Space and rockets. What do you think rockets have to do to get to space? I'll give you a hint, look at the words I made bold in your quote.

Quote from: robertotrevor on November 23, 2012, 08:34:51 AM

Quote from: sceptimatic on November 23, 2012, 07:41:55 AM

Quote from: robertotrevor on November 23, 2012, 06:27:39 AM

Quote from: ThinkingMan on November 23, 2012, 05:47:06 AM

Quote from: sceptimatic on November 23, 2012, 04:05:54 AM

That balloon experiment is simply expelling air against the atmosphere behind it, forcing the balloon forward, same with the balloon being on the car.

So that means a more robust substance behind the balloon should allow the balloon to move faster then, right? Let's put it in water then. Or even better, let's encase it in concrete and see how far it goes.

I think this is the best point against sceptimatics idea of the balloon experiment working because of earth atmosphere. Because all the atmosphere does is increase the resistance, so if according to him that is what makes it move, and that is why they would not work in space, a denser environment would mean more movement. But it doesn't.

It's a very bad point .

Explain why you would move less on the water or any other denser environment, if according to you is the push against this density (air resistance) that makes movements like this possible in earth, while no density in space (vacuum) would mean no movement.

I didn't mean it was a bad point as regards that, I meant it's a bad point to make as I'm not dealing with water or anything working better than anything else on Earth.

My argument is simply that the vacuum of space is( what we are told) a vacuum and a rocket will not work in the vacuum of the expanse of space.

Also wouldn't the "vacuum" of space suck the atmosphere off of the earth.

Quote from: sceptimatic on November 23, 2012, 08:42:56 AM

Quote from: robertotrevor on November 23, 2012, 08:34:51 AM

Quote from: sceptimatic on November 23, 2012, 07:41:55 AM

Quote from: robertotrevor on November 23, 2012, 06:27:39 AM

Quote from: ThinkingMan on November 23, 2012, 05:47:06 AM

Quote from: sceptimatic on November 23, 2012, 04:05:54 AM

That balloon experiment is simply expelling air against the atmosphere behind it, forcing the balloon forward, same with the balloon being on the car.

So that means a more robust substance behind the balloon should allow the balloon to move faster then, right? Let's put it in water then. Or even better, let's encase it in concrete and see how far it goes.

I think this is the best point against sceptimatics idea of the balloon experiment working because of earth atmosphere. Because all the atmosphere does is increase the resistance, so if according to him that is what makes it move, and that is why they would not work in space, a denser environment would mean more movement. But it doesn't.

It's a very bad point .

Explain why you would move less on the water or any other denser environment, if according to you is the push against this density (air resistance) that makes movements like this possible in earth, while no density in space (vacuum) would mean no movement.

I didn't mean it was a bad point as regards that, I meant it's a bad point to make as I'm not dealing with water or anything working better than anything else on Earth.

My argument is simply that the vacuum of space is( what we are told) a vacuum and a rocket will not work in the vacuum of the expanse of space.

Also wouldn't the "vacuum" of space suck the atmosphere off of the earth.

I have but one word for you. Gravity.

Quote from: ThinkingMan on November 23, 2012, 09:25:29 AM

Quote from: sceptimatic on November 23, 2012, 09:11:51 AM

Quote from: ThinkingMan on November 23, 2012, 09:02:25 AM

Quote from: sceptimatic on November 23, 2012, 08:23:15 AM

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

Gravity is always a factor. We were explaining the fundamentals of the laws of motion. Gravity is not a factor in the third law of motion, but it is a factor on the whole scale, i.e. what I said before, an object in motion will continue in motion until another force acts on it.

Quote from: sceptimatic on November 23, 2012, 08:44:49 AM

Quote from: robertotrevor on November 23, 2012, 08:39:56 AM

Quote from: sceptimatic on November 23, 2012, 08:23:15 AM

Quote from: ThinkingMan on November 23, 2012, 07:57:39 AM

Quote from: sceptimatic on November 23, 2012, 07:47:41 AM

This mass and weight only scenario to explain Newtons third law is genius really, because it allows the rocket working in space to actually be plausible.
The truth is, it's just as simple to experiment to prove Newtons law relies on all 4 , (mass/weight/atmosphere/gravity) to make anything act/react.

Weight is mass. Atmosphere is mass. Atmosphere interferes with thrust. You need more thrust to move in atmosphere than you do in a vacuum because of drag. And it's not just mass we're talking about, it's mass/energy. Gravity is a factor, it's one of Newton's laws. Also, inertia is part of the laws of motion. It says an object in motion will continue with that motion unless acted upon by another force, i.e. gravity, friction.

Oh, so now gravity is a factor?

It wasn't before by your explanations.

If you talk about weight, you are already taking gravity as a factor.

Don't be changing it now.

You and others said that it was mass and "not" gravity or air that caused the action/reaction.

No one said gravity does not cause the action/reaction, and also, no one said it does. Because guess what, gravity has nothing to do with how a rocket works. The rocket has to fight gravity and air resistance to go anywhere, be it up in space or into your front window. Everything here on earth's surface has to fight gravity and air resistance. Why do you think airplanes are so streamline looking, as well as rockets? If they were cube shaped, it would be much more difficult to keep them aloft.

Now, mass and energy are factors in the action/reaction. Just mass and energy. That's it. You're either not reading everything we say and picking out select words to try and troll with, or you're simply not comprehending it at all.

I'm not talking about a rocket overcoming gravity though, I was on about the medicine ball experiment and you saying gravity has nothing to do with it.

I'm talking about space and rockets. Not rockets overcoming Earth's gravity.

The medicine ball experiment is the same concept as a rocket. You're expelling a mass one way to move a mass another way.

Space and rockets. What do you think rockets have to do to get to space? I'll give you a hint, look at the words I made bold in your quote.

When I mentioned gravity to you earlier in the topic , with the medicine ball experiment, you denied gravity was a factor in it and said it was simply mass and energy.

Please quote me where I denied gravity as a factor. It does not contribute to the third law of motion. It only hinders continuous motion in this case.

Quote from: hoppy on November 23, 2012, 09:28:33 AM

Quote from: sceptimatic on November 23, 2012, 08:42:56 AM

Quote from: robertotrevor on November 23, 2012, 08:34:51 AM

Quote from: sceptimatic on November 23, 2012, 07:41:55 AM

Quote from: robertotrevor on November 23, 2012, 06:27:39 AM

Quote from: ThinkingMan on November 23, 2012, 05:47:06 AM

Quote from: sceptimatic on November 23, 2012, 04:05:54 AM

That balloon experiment is simply expelling air against the atmosphere behind it, forcing the balloon forward, same with the balloon being on the car.

So that means a more robust substance behind the balloon should allow the balloon to move faster then, right? Let's put it in water then. Or even better, let's encase it in concrete and see how far it goes.

I think this is the best point against sceptimatics idea of the balloon experiment working because of earth atmosphere. Because all the atmosphere does is increase the resistance, so if according to him that is what makes it move, and that is why they would not work in space, a denser environment would mean more movement. But it doesn't.

It's a very bad point .

Explain why you would move less on the water or any other denser environment, if according to you is the push against this density (air resistance) that makes movements like this possible in earth, while no density in space (vacuum) would mean no movement.

I didn't mean it was a bad point as regards that, I meant it's a bad point to make as I'm not dealing with water or anything working better than anything else on Earth.

My argument is simply that the vacuum of space is( what we are told) a vacuum and a rocket will not work in the vacuum of the expanse of space.

Also wouldn't the "vacuum" of space suck the atmosphere off of the earth.

Theoretically yes it would.

So, either space isn't what we are led to believe it is, or we have some kind of barrier protecting the Earth from this happening.

This is why the Earth can be explained in many ways and is why the FET,RET,even an Earth with a hollow in it can be debated because in truth, if everyone admitted it, we are only infants when it comes to knowing just what we are really a part of.

Those that go with the official line, simply accept what they are told and stick rigidly to that, even if some of it makes no sense at all.

If official science said the Earth was a pyramid and showed this from space and give reasons as to why we can't see a big pyramid point on Earth, it would be explained away with a chalk board full of brain zapping equations that any intelligent person would never even attempt to fathom out and those that did, would shout from the roof tops that it all adds up without having the faintest idea as to what it adds up to.

No, stupid people would not attempt these "brain zapping equations" you speak of. Intelligent people are the reason that we know what we know today. No one just made shit up.

Quote from: hoppy on November 23, 2012, 09:28:33 AM

Also wouldn't the "vacuum" of space suck the atmosphere off of the earth.

Theoretically yes it would.

So, either space isn't what we are led to believe it is, or we have some kind of barrier protecting the Earth from this happening.

This is why the Earth can be explained in many ways and is why the FET,RET,even an Earth with a hollow in it can be debated because in truth, if everyone admitted it, we are only infants when it comes to knowing just what we are really a part of.

Those that go with the official line, simply accept what they are told and stick rigidly to that, even if some of it makes no sense at all.

If official science said the Earth was a pyramid and showed this from space and give reasons as to why we can't see a big pyramid point on Earth, it would be explained away with a chalk board full of brain zapping equations that any intelligent person would never even attempt to fathom out and those that did, would shout from the roof tops that it all adds up without having the faintest idea as to what it adds up to.

Where is the chalk board full of complicated equations here? we are talking about basic stuff here, than can be verified with simple experiments, action/reaction, gravity. Gravity is what makes the atmosphere stay around the earth. "if official science said"... clearly you don't even know what means.

On a rocket lifting off from Earth, we know it hinders continuous motion. I'm not on about hindering though.

I'm on about it plays a factor in throwing the medicine ball and the reaction from throwing that medicine ball, along with the mass of the ball, plus the energy in releasing the ball, plus friction, although in a minor role against the mass.
A beach ball would simply have friction as it's major force with gravity and mass having minimal effect.

I didn't know you were talking about the medicine ball when i answered about rockets, I think that was the problem. In the medicine ball experiment, gravity has nothing to do with the movement. It is present because we are on earth... but it doesn't help with the movement.

On a rocket lifting off from Earth, we know it hinders continuous motion. I'm not on about hindering though.

But it does hinder. It pulls you and the chair down, along with the atmosphere, so that when you throw the ball, there is friction from the atmosphere and the floor and it slows your movement.

I'm on about it plays a factor in throwing the medicine ball and the reaction from throwing that medicine ball, along with the mass of the ball, plus the energy in releasing the ball, plus friction, although in a minor role against the mass.
A beach ball would simply have friction as it's major force with gravity and mass having minimal effect.

It doesn't play a factor in "the reaction from throwing the medicine ball." The only two factors in that are the mass of the ball and the mass of you + the chair (object to be moved). A beach ball has a lot less mass, so if you moved at all, it would be so very little as to not be noticed. Friction is not part of the third law of motion.

For instance, imagine picking up a cannon ball. It's heavy right? really heavy. Now think of holding that cannon ball on a skateboard.
Tip that cannon ball out of your hands and it will drop straight to the floor, because you have put no pushing motion into it and allowed gravity to take over the mass of the ball, so you just stay put.
I think you can accept that right?

Ok, now pick that cannonball up and throw it straight up and you will find that you expend a lot of energy in doing that, whilst also feeling your skateboard bend slightly with the downward force of gravity, plus mass against your upward force right?

Ok, now we go for the throwing the ball away from yourself. Imagine holding the ball up to chest height and launching it away from you.
The second you apply energy to that ball to launch it, gravity is immediately also acting on the mass of that ball and pushing it down against your energy in pushing it outwards forcing your skateboard backwards due to the mass and gravity acting together.


I'm sure you can understand this.

Now imagine floating in space on that skate board.
There is no up,down,sideways, forward or back, it's simply nothing and you are nothing in space and neither is the skateboard or the cannon ball.

You can launch that cannon ball above your head, below...sideways and you will feel no force of it because it weighs nothing and has no "mass"

Now although you could launch that cannonball, there is no reaction to your body because there is nothing to push you back as space is devoid of matter.

If you were just floating in space on your own and flapped your arms, kicked your feet, pushed out arms outwards with the same action you earlier launched the cannon ball...you would go nowhere because you are simply pushing against nothing but yourself. You are suspended.

That doesn't make sense, because i push it to one side and the gravity pulls it down i move to the other side? that is pure sceptimatic's logic... Gravity is always acting on the ball and on me, not only the second I release it. So why would that happen when I let the ball go? try pushing that heavy ball forward without dropping it. You will move a little back but will be stopped because of the ball trying to move in the opposite direction while attached to you, but you are still pushing to one side with your arms counteracting gravity.

It does where the mass of the object thrown is denser.

Density is irrelevant. Total mass is what is relevant.

For instance, imagine picking up a cannon ball. It's heavy right? really heavy. Now think of holding that cannon ball on a skateboard.
Tip that cannon ball out of your hands and it will drop straight to the floor, because you have put no pushing motion into it and allowed gravity to take over the mass of the ball, so you just stay put.
I think you can accept that right?

Ok, now pick that cannonball up and throw it straight up and you will find that you expend a lot of energy in doing that, whilst also feeling your skateboard bend slightly with the downward force of gravity, plus mass against your upward force right?

Ok, now we go for the throwing the ball away from yourself. Imagine holding the ball up to chest height and launching it away from you.
The second you apply energy to that ball to launch it, gravity is immediately also acting on the mass of that ball and pushing it down against your energy in pushing it outwards forcing your skateboard backwards due to the mass and gravity acting together.

I actually cannot accept that. The only reason you are push backward is because you are forcing an object with a lot of mass away from you. Mass is independent of gravity. Gravity has no bearing on the third law of motion. Gravity is only relevant in you throwing the ball upwards, as gravity attracts towards the center of mass.

I'm sure you can understand this.

I understand your misconception, yes. I'm trying to help you rectify it.

Now imagine floating in space on that skate board.
There is no up,down,sideways, forward or back, it's simply nothing and you are nothing in space and neither is the skateboard or the cannon ball.

You can launch that cannon ball above your head, below...sideways and you will feel no force of it because it weighs nothing and has no "mass"

There is still mass in space. There is mass everywhere. Mass is simply "the amount of matter in an object." You're thinking of weight, which has no bearing on the laws of motion. Weight is a function of gravity. If you're in orbit, you're in constant freefall, and therefore "weightless" because you're tangential speed to gravity has counteracted gravities effects in your frame of reference.

Now although you could launch that cannonball, there is no reaction to your body because there is nothing to push you back as space is devoid of matter.

Actually, if you push on the cannon ball, you will both move. If the cannon ball has more mass than your body, your body will move more. If your body has more mass than the cannon ball, then the cannon ball will more more. That's what the third law of motion states.

If you were just floating in space on your own and flapped your arms, kicked your feet, pushed out arms outwards with the same action you earlier launched the cannon ball...you would go nowhere because you are simply pushing against nothing but yourself. You are suspended.

Actually, if you flap your limbs in just the right way, it will cause you to "move" in your frame of reference as you will be shifting your center of mass around. This is similar to lurching back and forth in a wheelchair without the wheel locks on. You've can't swim in space, as that requires something to push against. You also won't get very far throwing your mass around, you probably won't even move enough to notice, unless you're right up next to something, then you may notice.

Not sure why I'm bothering...but here we go:

You can launch that cannon ball above your head, below...sideways and you will feel no force of it because it weighs nothing and has no "mass"

Of course it has mass.  It doesn't have weight, but this is irrelevant.

Now although you could launch that cannonball, there is no reaction to your body because there is nothing to push you back as space is devoid of matter.

The equal and opposite reaction pushes you back.  This is Newton's third law, and it operates wherever you are.

If you were just floating in space on your own and flapped your arms, kicked your feet, pushed out arms outwards with the same action you earlier launched the cannon ball...you would go nowhere because you are simply pushing against nothing but yourself. You are suspended.

Quite.  Now take off a shoe and throw it - you will move in the opposite direction with the same momentum as the shoe.

Quote from: RealScientist on November 23, 2012, 06:33:56 AM

Quote from: ThinkingMan on November 23, 2012, 05:47:06 AM

What you don't seem to understand is rocket propulsion isn't like swimming. When you're swimming, you're fuel is the water around you, your thrust is pushing the water back. It's difficult and extremely inefficient. When a rocket goes, it's fuel is in the tank. It burns this fuel to create a more energetic thrust. By burning it, the mass/energy moves faster out of the nozzles than it would have just being pumped out. So the rocket goes in the opposite direction of the force.

What he does not understand is the complete Third Newton's Law of Motion. He has accepted this fact but still talks like he knew what he was saying when an experiment that is based on that law passes through his head.

I think he knows that we have answered every single question he has raised around this subject.

The biggest problem is you and others only half understanding Newtons third law of motion. You completely neglect the atmosphere or gravity and simply use mass and weight. It's all of them.

Stop the presses, call Stockholm, in fact, stop this civilization on its tracks!!!

Not even Newton understood his own Third Law of Motion! Every machine created since the Industrial Revolution was designed wrong!!!

Newton, in his incredible ineptitude, forgot to include the atmosphere and gravity in his Third Law of Motion!!! And every scientist of the last 300 years or so has also missed the error!!!

Thank the Average Joe (a.k.a. sceptimatic) for finally understanding that the Third Law of Motion is the effect of the atmosphere and gravity on the movement of rockets!!!

OK, I promise I will laugh at Average Joe a little less in the future.

how are you going to demonstrate that to us?

you're not demonstrating anything.

fuel isn't released from a rocket in space. do you even have an inkling of how rockets work?

I agree that the ball has mass because it has matter, fair enough, but what I am trying to say is, the matter in the cannon ball would be of no consequence because space renders it weightless.

You do you understand that even though an object is rendered weightless, it still has mass, don't you?

Fuel isn't released from a rocket in space? Hmmmm.
So are you saying that the rocket works by keeping a tank of fuel and not expelling it?

No, fuel is not released out the back of a rocket.  A rocket works by burning fuel and expelling the gasses out the back.

Ok , just answer this simple question.
If you were sat in a wheelchair and had a cannon ball.....You throw that cannon ball away from you in a straight line and your friend who happened to weigh exactly the same as you and had the exact same wheelchair and a matching cannonball, threw his cannon ball at an upwards angle, who would move further back?

Why don't you just make your point? the one pushing it to one side.

Yes I know a rocket burns fuel.

I just want to know how it expels the fuel from the tank to achieve this constant high pressure burn.

A rocket doesn't "expel" fuel.  It pumps fuel and oxidizer into a combustion chamber where they are burned.  This burning releases a great deal of energy in the form of rapidly expanding gasses that are expelled out the back.

Quote from: markjo on November 23, 2012, 05:24:19 PM

Quote from: sceptimatic on November 23, 2012, 05:13:14 PM

Yes I know a rocket burns fuel.

I just want to know how it expels the fuel from the tank to achieve this constant high pressure burn.

A rocket doesn't "expel" fuel.  It pumps fuel and oxidizer into a combustion chamber where they are burned.  This burning releases a great deal of energy in the form of rapidly expanding gasses that are expelled out the back.

What do the rapidly expanding gases actually do to propel the rocket?

Why do I get the feeling that we've been over this before?

Again, it has to do with unbalanced forces within the rocket engine.  The gasses push out in all directions against the combustion chamber except where they can escape out through the "throat" of the engine.

http://en.wikipedia.org/wiki/Rocket_engine

Quote from: markjo on November 23, 2012, 05:42:16 PM

Quote from: sceptimatic on November 23, 2012, 05:27:32 PM

Quote from: markjo on November 23, 2012, 05:24:19 PM

Quote from: sceptimatic on November 23, 2012, 05:13:14 PM

Yes I know a rocket burns fuel.

I just want to know how it expels the fuel from the tank to achieve this constant high pressure burn.

A rocket doesn't "expel" fuel.  It pumps fuel and oxidizer into a combustion chamber where they are burned.  This burning releases a great deal of energy in the form of rapidly expanding gasses that are expelled out the back.

What do the rapidly expanding gases actually do to propel the rocket?

Why do I get the feeling that we've been over this before?

Again, it has to do with unbalanced forces within the rocket engine.  The gasses push out in all directions against the combustion chamber except where they can escape out through the "throat" of the engine.

http://en.wikipedia.org/wiki/Rocket_engine

So what is the burning fuel pushing against to make the rocket move?

Are you saying that it's actually pushing against the rocket itself?

The gasses are pushing against the combustion chamber which is a part of the rocket engine which is a part of the rocket.  So yes, in a roundabout way, the exhaust gasses are pushing against the rocket itself.

You do see how silly this sounds don't you.

Oh I know I'll get told I don't understand rocket physics and all that but you see, it seriously makes no sense whatsoever.

In an atmosphere it's not hard to understand how a rocket works, in space it's relied on Newtons third law but I do not see how a burn or exhaust can propel a rocket in space, I really can't.

It's like someone asking me to lift myself up by grabbing my own legs with my own arms.
Don't get me wrong, it's genius in the way it's told as to how they work in space but the reality is, it's absolutely impossible.

What i can't understand is why you think this doesn't works on space if it does on earth. The only thing the atmosphere does with this is add density.
If there is an explosion, it will push you, weather you are on earth or on space, i told you this before, you accepted it, but the thing you questioned then was "weather or not an explosion could happen in space". But now it seems you have changed your mind.

Oh I know I'll get told I don't understand rocket physics and all that but you see, it seriously makes no sense whatsoever.

In an atmosphere it's not hard to understand how a rocket works, in space it's relied on Newtons third law but I do not see how a burn or exhaust can propel a rocket in space, I really can't.

If you think that there is a difference between how a rocket works in an atmosphere and how it works in an atmosphere, then you're right, you don't understand rocket physics or Newton's third law.  I think that we've reached the point where if you don't understand it by now, then we can't explain it in a way that you will.