Post by alex04 on Jul 13, 2007 20:39:02 GMT -4
I had a bit of a long running discussion with a conspiracy theorist recently, after being exasperated at the 'i've made the assumption so that proves it's a hoax' logic i decided to see what his specific problem with it was. I also apologise for the length of this - i've tried to cut out as much as possible.
To be fair, the guy was pretty civil, and was trying to ask genuine questions. Just kinda lost as to why he did research them himself. Anyway.
The video in question was to do with the famous 'hammer and feather' release experiment. I've started this from the point the argument got civil
The one thing that made him fairly suspicious (among a few other things), was that there was no effect on the feather when it was released in space. I opined that i wouldn't expect to see anything, so i asked what he would expect the feather to do - and why -
"there is a reasonable basis for the feather being damaged the moment it left the LM and entered moon vaccume. Well, before he drops it it looks in pristine condition. Makes me suspicious."
I asked, why not try asking these questions, in the interests of being objective with your own claim -
- what happens to organic material when released in a space environment?
- what experiments have already been performed in space that are not consistent with the video?
- what happened to the feather? (it's not clear at all in the video if the feather was slightly damaged or not)
- Experiment by heating a body of soft dirt (not a hot plate) up to the assumed 200deg, and see what happens when a feather is dropped onto it
- How is any of this inconsistent with the video?
reply
"It is inconsistent with the video because the boiling point of water goes down to almost -273 degrees celcius when you take water to an area with zero pressure. Considering the feather will still contain trapped molecules of water, oxygen, nitrogen etc and it is also composed partly of protein tissue(carbon, hydrogen, oxygen and nitrogen) which are very unstable at hight temperatures and will be EXTREMELY unstable at low pressure."
So i decided to humour him and research the issue.
I started by looking for experiments that NASA had performed in space (although that could be called 'fake', as NASA is not reputable
) - mainly looking for experiments where organic material had been released in space. I was unsuccessfull, although obviously i didn't look hard enough as i've since found some info on this.
Then i found some accounts where humans had actually been exposed to vaccums / low pressure. I found an account where some cosmonauts had been exposed, and were found dead when they retrieved the capsule. They looked unaffected - like they were asleep, it stated. There were other accounts at high altitude where people had passed out, but the last thing they remembered was the saliva on their tongue starting to boil. Why then, would the rest of the body not be affected? (sweat glands, and the like).
A friend of mine offered a very simple (and obvious suggestion) - why not just throw the feather into an oven or microwave, and see if you can observe any effects? (assuming that there are any trapped water molecules etc.)
Discussion went as:-
Me-
Here's an experiment you can try at home (to help back up your claim). Pre-heat your oven to 101 degrees C (or higher - to push the water molecules to boiling point), put the feather in the oven. If the feather reacts to this, then you clearly have a strong case. Let me know how you go -- I'm quite interested in hearing the outcome. This would add some evidence to your speculation - assuming that it does in fact warp the feather.
CT
This experiment may not work. The problem is that an oven on earth is at 1 atmospheric pressure. The lower the pressure, the lower the boiling point of ANY liquid including water. As pressure tends to zero, in theoretical physics, the boiling point of water also lowers to almost -273 degrees celcius(absolute zero temperature). In other words, water turns to steam much much faster in vaccum(space) because the pressure does not keep it "pressed" into liquid form.
Me-
The point of the experiment is to boil away any water molecules to observe the effect on the feather. Alternatively you could microwave it. (high power for 20 minutes). If there is enough water there to have the effect that you're predicting, then surely something will happen, however minor. The pressure is irrelevant because when the water molecules reach 100C they will change state and try to escape regardless (you cant try and tell me that at 120c/1atmsphr the water will still be in a liquid state). Short of having a vacuum chamber this is the only way i know to try and test the theory. Furthermore, bird feathers are effectively dead matter, like fingernails or hair. I believe there is no reason to suspect it would react severely upon being released into space.
CT
No the pressure is not irrelevent. See, when liquid water turns to gaseous steam at 1 atmosphere(earth pressure) another interesting phenomenon also occurs. The volume of H20 increases by 1600 times! I cannot stress the significance of this expansion enough, imagine if every moist area of a feather suddenly needed upto 1600 times more space to exist in...
Me- (i conceded the point as i could not disprove it, although i did mention maybe there was simply not enough to cause an obvious effect)
I don't understand why it's not worth trying the experiment though? Short of access to a vacuum chamber (which i am in fact about to ask about), i don't know any other way to produce empirical evidence, which unfortunately leaves you with pure speculation.
Nonetheless, i contacted AVS.org who specialise in Vacuum related experiments. I got the following replies.
Robert Waits (rwaits@gmail.com)
Good question. As you probably know, this experiment demonstrates the objects with different mass fall at the same rate under the influence of gravity. This was also the point of Galileo's famous demonstration from the Tower of Pisa using two objects of greatly differing mass. I am not familiar with the experiment on the moon, but it would demonstrate the same effect. I did a search of 'Feather and Guinea' (the name of the original vacuum demonstration) on the web and came up with this site: physics.kenyon.edu/EarlyApparatus/Pneumatics/Guinea_and_Feather_Tube/Guinea_and_Feather_Tube.html
I am not sure if Newton was really the first to do this experiment, but further searches might provide the answer.
We have done this experiment in a short tube at science teachers workshops. It is difficult to do because it is hard to keep the feather from being electrostatically attracted and sticking to the plastic wall of the vacuum container. If all goes well, the feather and a 3-gram metal coin fall at the same rate.
But none of this answers your question, however you are correct, the small amount moisture adsorbed on the feather surface would 'outgas' from the surface and any moisture within the feather would evaporate. During this process, the feather actually is cooled (by the heat of vaporization of the water). I am not an expert on feather structure, but moisture within a cell could cause the cells to eventually disrupt under vacuum. In our experiments under a moderate vacuum, we have not noticed any obvious effect on the feather. Drying the feather in a warm oven would remove surface moisture, but it would be re-adsorbed from humid air before you could transfer it to the vacuum chamber.
Hopes this helps. Were any bets involved?
Robert Waits
----------------------------------
and
----------------------------------
David B Webb [vacuatech@juno.com]
You raise a very interesting question. All of Robert's comments in his response are entirely correct. Gas transfer from the surface of any object placed in a lower pressure (vacuum) into the free space, immediately starts and continues layer by layer, until the valance bond to the surface is stronger than the desorption effect. The addition of heat to the object would hasten the desorbtion rate, as well as the total amount desorbed, but as Robert pointed out, the reverse happens on cooling the object.
Robert, I and others in our Chapter have performed many hundreds of the "Guinea and Feather" experiments for students, but I've never heard of any comments on the distortion on the feather. Of course, we have chickens so rarely do I re-use a feather. Thinking of the expanding marshmellow in a vacuum experiment, where the walls of the gas bubbles within the marshmellow collapse, when atmospheric pressure is re-introduced into the vacuum chamber, I would think most of the feather structure would resist any collapse, with just a one bar pressure differential.
I will try to remember looking at the feather appearance, before and after, when running future "Guinea and Feather" experiments. However, it may be difficult to visually measure any change in appearance, with such a feathery object, if you excuse the pun.
regards, Dave
-------------------------------------------------------
Also posted a question regarding the science comments, on the Australian ABC Self service science forum, and got the following responses.
-------------------------------------------------------
"As pressure tends to zero, in theoretical physics, the boiling point of water also lowers to almost -273 degrees celcius(absolute zero temperature)."
This is not true.
It is true that liquid water is not stable at very low pressures, only ice and vapour are. Whether the liquid water freezes or boils upon being subjected to a vacuum depends on its initial temperature and its volume.
If the feather was brought down to ambient temperature before being subjected to a vacuum then any water on it would freeze (Actually it would already have frozen).
If the feather was at normal room temperature before being subjected to vacuum then the water would boil off it until it lost enough temperature via radiation to freeze.
The notion that the water explosively boiling off the surface will cause some reaction is sound in principle but you need to subject it to closer scrutiny. What is the total mass of water relative to the mass of the feather? It is fine to say there will be a reaction in principle but if the total water content is (say) 0.1% of the mass of the feather then no matter how explosive the boiling is, you will not see anything.
Furthermore you will only notice effects from *asymmetrical* boiling. If the water boils off equally in all directions then all of these reactions will cancel out, and the only effect will be a mass reduction - which has no impact on the gravitational descent!
Unless your interlocutor can come up with some reason why the total water mass will be a *significant* fraction of the total mass of the feather, and that the boiling will be *significantly* directional then the idea has no legs.
I think the first thing to do would be to place the feather in a vacuum chamber, and see if that achieves anything. I suspect it won't.
As for temperature, the feather used on Apollo 15 sat inside the LM before it was used, and for some of this time it was in a vacuum (the cabin was depressurised for each moon walk. When it was taken out for the third moon walk, the astronaut kept it in a suit pocket, and therefore out of direct sunlight, until it was used. The spacesuit was coloured white to reflect as much solar radiation as possible.
Therefore, by the time the feather was produced for the experiment, its temperature wouldn't have changed significantly from room temperature.
On that basis, it would be reasonable to try out a room temperature feather in the vacuum chamber.
Having said all that, does your colleague have any arguments which explain why a Moon landing mission would have been impossible?
May I recommend a visit to www.clavius.org for you and your colleague - you'll both learn a lot.
-----------------------------------------------------------
Anyway, end result - he conceded, and it was debunked.
Then it went to - 'well what about the effect of the feather on the moon's surface?'
My reply was basically - 'go research it!!!'
To be fair, the guy was pretty civil, and was trying to ask genuine questions. Just kinda lost as to why he did research them himself. Anyway.
The video in question was to do with the famous 'hammer and feather' release experiment. I've started this from the point the argument got civil
The one thing that made him fairly suspicious (among a few other things), was that there was no effect on the feather when it was released in space. I opined that i wouldn't expect to see anything, so i asked what he would expect the feather to do - and why -
"there is a reasonable basis for the feather being damaged the moment it left the LM and entered moon vaccume. Well, before he drops it it looks in pristine condition. Makes me suspicious."
I asked, why not try asking these questions, in the interests of being objective with your own claim -
- what happens to organic material when released in a space environment?
- what experiments have already been performed in space that are not consistent with the video?
- what happened to the feather? (it's not clear at all in the video if the feather was slightly damaged or not)
- Experiment by heating a body of soft dirt (not a hot plate) up to the assumed 200deg, and see what happens when a feather is dropped onto it
- How is any of this inconsistent with the video?
reply
"It is inconsistent with the video because the boiling point of water goes down to almost -273 degrees celcius when you take water to an area with zero pressure. Considering the feather will still contain trapped molecules of water, oxygen, nitrogen etc and it is also composed partly of protein tissue(carbon, hydrogen, oxygen and nitrogen) which are very unstable at hight temperatures and will be EXTREMELY unstable at low pressure."
So i decided to humour him and research the issue.
I started by looking for experiments that NASA had performed in space (although that could be called 'fake', as NASA is not reputable
) - mainly looking for experiments where organic material had been released in space. I was unsuccessfull, although obviously i didn't look hard enough as i've since found some info on this.Then i found some accounts where humans had actually been exposed to vaccums / low pressure. I found an account where some cosmonauts had been exposed, and were found dead when they retrieved the capsule. They looked unaffected - like they were asleep, it stated. There were other accounts at high altitude where people had passed out, but the last thing they remembered was the saliva on their tongue starting to boil. Why then, would the rest of the body not be affected? (sweat glands, and the like).
A friend of mine offered a very simple (and obvious suggestion) - why not just throw the feather into an oven or microwave, and see if you can observe any effects? (assuming that there are any trapped water molecules etc.)
Discussion went as:-
Me-
Here's an experiment you can try at home (to help back up your claim). Pre-heat your oven to 101 degrees C (or higher - to push the water molecules to boiling point), put the feather in the oven. If the feather reacts to this, then you clearly have a strong case. Let me know how you go -- I'm quite interested in hearing the outcome. This would add some evidence to your speculation - assuming that it does in fact warp the feather.
CT
This experiment may not work. The problem is that an oven on earth is at 1 atmospheric pressure. The lower the pressure, the lower the boiling point of ANY liquid including water. As pressure tends to zero, in theoretical physics, the boiling point of water also lowers to almost -273 degrees celcius(absolute zero temperature). In other words, water turns to steam much much faster in vaccum(space) because the pressure does not keep it "pressed" into liquid form.
Me-
The point of the experiment is to boil away any water molecules to observe the effect on the feather. Alternatively you could microwave it. (high power for 20 minutes). If there is enough water there to have the effect that you're predicting, then surely something will happen, however minor. The pressure is irrelevant because when the water molecules reach 100C they will change state and try to escape regardless (you cant try and tell me that at 120c/1atmsphr the water will still be in a liquid state). Short of having a vacuum chamber this is the only way i know to try and test the theory. Furthermore, bird feathers are effectively dead matter, like fingernails or hair. I believe there is no reason to suspect it would react severely upon being released into space.
CT
No the pressure is not irrelevent. See, when liquid water turns to gaseous steam at 1 atmosphere(earth pressure) another interesting phenomenon also occurs. The volume of H20 increases by 1600 times! I cannot stress the significance of this expansion enough, imagine if every moist area of a feather suddenly needed upto 1600 times more space to exist in...
Me- (i conceded the point as i could not disprove it, although i did mention maybe there was simply not enough to cause an obvious effect)
I don't understand why it's not worth trying the experiment though? Short of access to a vacuum chamber (which i am in fact about to ask about), i don't know any other way to produce empirical evidence, which unfortunately leaves you with pure speculation.
Nonetheless, i contacted AVS.org who specialise in Vacuum related experiments. I got the following replies.
Robert Waits (rwaits@gmail.com)
Good question. As you probably know, this experiment demonstrates the objects with different mass fall at the same rate under the influence of gravity. This was also the point of Galileo's famous demonstration from the Tower of Pisa using two objects of greatly differing mass. I am not familiar with the experiment on the moon, but it would demonstrate the same effect. I did a search of 'Feather and Guinea' (the name of the original vacuum demonstration) on the web and came up with this site: physics.kenyon.edu/EarlyApparatus/Pneumatics/Guinea_and_Feather_Tube/Guinea_and_Feather_Tube.html
I am not sure if Newton was really the first to do this experiment, but further searches might provide the answer.
We have done this experiment in a short tube at science teachers workshops. It is difficult to do because it is hard to keep the feather from being electrostatically attracted and sticking to the plastic wall of the vacuum container. If all goes well, the feather and a 3-gram metal coin fall at the same rate.
But none of this answers your question, however you are correct, the small amount moisture adsorbed on the feather surface would 'outgas' from the surface and any moisture within the feather would evaporate. During this process, the feather actually is cooled (by the heat of vaporization of the water). I am not an expert on feather structure, but moisture within a cell could cause the cells to eventually disrupt under vacuum. In our experiments under a moderate vacuum, we have not noticed any obvious effect on the feather. Drying the feather in a warm oven would remove surface moisture, but it would be re-adsorbed from humid air before you could transfer it to the vacuum chamber.
Hopes this helps. Were any bets involved?
Robert Waits
----------------------------------
and
----------------------------------
David B Webb [vacuatech@juno.com]
You raise a very interesting question. All of Robert's comments in his response are entirely correct. Gas transfer from the surface of any object placed in a lower pressure (vacuum) into the free space, immediately starts and continues layer by layer, until the valance bond to the surface is stronger than the desorption effect. The addition of heat to the object would hasten the desorbtion rate, as well as the total amount desorbed, but as Robert pointed out, the reverse happens on cooling the object.
Robert, I and others in our Chapter have performed many hundreds of the "Guinea and Feather" experiments for students, but I've never heard of any comments on the distortion on the feather. Of course, we have chickens so rarely do I re-use a feather. Thinking of the expanding marshmellow in a vacuum experiment, where the walls of the gas bubbles within the marshmellow collapse, when atmospheric pressure is re-introduced into the vacuum chamber, I would think most of the feather structure would resist any collapse, with just a one bar pressure differential.
I will try to remember looking at the feather appearance, before and after, when running future "Guinea and Feather" experiments. However, it may be difficult to visually measure any change in appearance, with such a feathery object, if you excuse the pun.
regards, Dave
-------------------------------------------------------
Also posted a question regarding the science comments, on the Australian ABC Self service science forum, and got the following responses.
-------------------------------------------------------
"As pressure tends to zero, in theoretical physics, the boiling point of water also lowers to almost -273 degrees celcius(absolute zero temperature)."
This is not true.
It is true that liquid water is not stable at very low pressures, only ice and vapour are. Whether the liquid water freezes or boils upon being subjected to a vacuum depends on its initial temperature and its volume.
If the feather was brought down to ambient temperature before being subjected to a vacuum then any water on it would freeze (Actually it would already have frozen).
If the feather was at normal room temperature before being subjected to vacuum then the water would boil off it until it lost enough temperature via radiation to freeze.
The notion that the water explosively boiling off the surface will cause some reaction is sound in principle but you need to subject it to closer scrutiny. What is the total mass of water relative to the mass of the feather? It is fine to say there will be a reaction in principle but if the total water content is (say) 0.1% of the mass of the feather then no matter how explosive the boiling is, you will not see anything.
Furthermore you will only notice effects from *asymmetrical* boiling. If the water boils off equally in all directions then all of these reactions will cancel out, and the only effect will be a mass reduction - which has no impact on the gravitational descent!
Unless your interlocutor can come up with some reason why the total water mass will be a *significant* fraction of the total mass of the feather, and that the boiling will be *significantly* directional then the idea has no legs.
I think the first thing to do would be to place the feather in a vacuum chamber, and see if that achieves anything. I suspect it won't.
As for temperature, the feather used on Apollo 15 sat inside the LM before it was used, and for some of this time it was in a vacuum (the cabin was depressurised for each moon walk. When it was taken out for the third moon walk, the astronaut kept it in a suit pocket, and therefore out of direct sunlight, until it was used. The spacesuit was coloured white to reflect as much solar radiation as possible.
Therefore, by the time the feather was produced for the experiment, its temperature wouldn't have changed significantly from room temperature.
On that basis, it would be reasonable to try out a room temperature feather in the vacuum chamber.
Having said all that, does your colleague have any arguments which explain why a Moon landing mission would have been impossible?
May I recommend a visit to www.clavius.org for you and your colleague - you'll both learn a lot.
-----------------------------------------------------------
Anyway, end result - he conceded, and it was debunked.
Then it went to - 'well what about the effect of the feather on the moon's surface?'
My reply was basically - 'go research it!!!'
