What is the mass of a feather?

[somebody_else]

First set up a system of rotating masses that are perfectly* in balance. Then simply attach a feather a known distance away from the axis of rotation and a known distance along the shaft. Change the angular velocity of the masses, such that you reach resonance. Use this frequency to determine the total mass of the feather, while taking into account the system's dampening coefficient. Of course there are issues of proximity of the feather's velocity being close to the speed of light, as such the mass increase would be detected; and also the distance the feather is from axis will be changing due to relativistic effects on the support arm.

Ideally this set up would be vertical (relative to the Earth's centre of mass) such that the acceleration due to gravity is not oscillating due to the change in distance between the centre of the Earth and the feather. Make sure to calculate the Elastic modulus of the support arm and its 2nd moment of inertia throughout the arm, so the deflection can be calculated.

The alternative could be to fire the feather at venus so it collides with a known velocity at the planet's apohelion. The change in perihelion could find the mass of a feather as well.

[Technical Ben]

How about just cutting it up, and rotating it 5 times? Then you can weigh the second feather you have.

[fusama]

Isn't this obvious? Compress the feather to such a density for it to become a black hole and measure the radius of the event horizon. Using the formula for the Schwarzschild radius you can easily solve for the mass. Remember not to let the black hole rotate, or the formula won't work. Compressing the feather into a black hole, and measuring the radius of the event horizion before Hawking Radiation evaporates away the black hole are left as an exercise for the reader. Alternatively, you could measure the Hawking Radiation...

[Technical Ben]

Think we've had that one already.

[KrO2]

1. Obtain an arbitrarily large number of identical feathers using the Banach-Tarski method, or any other method of lesser awesomeness.
2. Strategically position a barrier of known thickness, density, et cetera.
3. Observe quantum tunneling.
4. Use the average length of time needed for quantum tunneling to occur to calculate its probability.
5. Solve the relevant equations for mass.
6. Sell the feathers at a price unmatchable by anyone who did not produce them purely by mathematics.
7. Profit.

[Roĝer]

Wow, a profit plan in which the penultimate step is actually known!

Anyway, I would suggest going into an ancient treasure cave, the type which Indiana Jones runs into regularly, and try with how many feathers (in a bag, of course) you need to replace the antique treasure to not get crushed by a boulder. Afterwards, sell the treasure to a goldsmith, divide the value by the market price of gold or whatever it was made of, and you have your answer.

[KrO2]

Well, I had an infinite amount of feathers lying around and wasn't sure what to do with them. Since the value of feathers will drop with each feather while I'm flooding the market, I wonder whether my total profit converges to a finite value and I get rich or it diverges to an infinite total and I get really rich.

Alternatively, you could measure the weight of the feather on Earth and on the Moon. Correct for the differing force of gravity due to the masses, and the difference is caused by buoyancy. Dividing by the density of air will yield the volume of the feather. Paint the density of the feather pink and erect an S.E.P. field around it, and with that problem out of the way, finding the mass is trivial.

[Giallo]

1) Go to paradise
2) Kill everybody there and weight their hearts
3) Do the same in hell

Since the gods compare the weight of the heart of a person with the weight of a feather in order to send that person to paradise or hell, the gods can not be wrong and the feather chosen by the gods is obviously THE FEATHER, you have now a good interval containing without any doubt the weight of THE FEATHER.

(I'm sorry for my poor english, but I'm swiss...)

[Aelfyre]

Well, I had an infinite amount of feathers lying around and wasn't sure what to do with them. Since the value of feathers will drop with each feather while I'm flooding the market, I wonder whether my total profit converges to a finite value and I get rich or it diverges to an infinite total and I get really rich.

Alternatively, you could measure the weight of the feather on Earth and on the Moon. Correct for the differing force of gravity due to the masses, and the difference is caused by buoyancy. Dividing by the density of air will yield the volume of the feather. Paint the density of the feather pink and erect an S.E.P. field around it, and with that problem out of the way, finding the mass is trivial.

technically if you had an infinite number of feathers lying around they would collapse into a singularity and render that (among many others) question moot.

[Technical Ben]

The answer is easy then. The feather has infinite mass.

Oh, wait. Black holes have no hair. Or feathers for that matter. So you cannot distinguish the one feather from the group of infinite feathers. Perhaps I should divide the infinite set by an infinite amount to get my feather back?

[Soralin]

The answer is easy then. The feather has infinite mass.

Oh, wait. Black holes have no hair. Or feathers for that matter. So you cannot distinguish the one feather from the group of infinite feathers. Perhaps I should divide the infinite set by an infinite amount to get my feather back?

Well if it has infinite mass, and no feathers, then the mass of a feather must be ∞/0

[Technical Ben]

Doh. I thought vague references to that would slip under the radar. You know what you've done now right?!

[Ptharien's Flame]

Doh. I thought vague references to that would slip under the radar. You know what you've done now right?!

Invoked a form unresolvable by L'Hospital's rule?

[pizzazz]

In order to standardize our feathers, we kill off all birds but one, then clone one feather from that bird, and then kill that bird.

Next, determine the curvature of the universe. Then if omega is not 1, just drop two feathers and see how quickly they go together/apart. Make sure that your experiment takes place over a long enough distance to get a reasonably smooth changes in the local average density (80 billion light years should be sufficient).

If the universe is flat, we must revert to our original plan. Take light-emitting device capable of emitting one wavelength at a time with sufficiently long-lasting battery so that it does not change brightness over the course of the experiment and seal it into a perfectly insulated chamber full of gas at known pressure, temperature, and heat capacity. Emit one wavelength of light, measure the temperature chage, and thus heat released, and thus the energy output. This allows you to calculate the wavelength of emitted. Now, you can drop a large number of feathers onto one side of a catapult to launch the light emitter straight up through a large gravityless vacuum, making sure it stays pointed correctly, and emit another wavelength a standard time unit later. Calculate its velocity via redshift, simple mechanics takes care of the mass of the many feathers, divide.

[Tomlidich]

design a small air compressor powered gun to fire feathers into blocks of clay.
measure the penetration, the speed at which they were fired, (gonna need to buy a high speed camera for this)
and extrapolate your data from there. for consistent results you will need to do this a few thousand times, per species of bird. then just average it.

you should get a fairly accurate result within a year or so.

[MHD]

1. Replicate feather Banach-Tarski wise.
2. Compress N feathers into a uniform solid block of known volume V.
3. Fire a bullet with known mass, hydro-dynammic shape parameters and kinetic energy into the feathers.
4. Calculate density D from penetration depth, and mass M from density D via the V.
5. Divide the mass M by N.

ALTERNATELY

1. Accelerate feather to 86.6% c.
2. Collide feather with something.
3. Measure released energy.
4. Find the mass of a ball of anitmatter that when annihilated with regular matter releases same amount of energy, then double that mass.

[ibgdude]

1. Take the feather to a location in space where gravity is zero. (some wait may be required.)
2. Place a clock near it.
3. Record the time dilation of the clock relative to your own, far, far distant one.
4. Use T=t(1-2GM/rc²)^.5, and solve for M. T is the nearby clock's time, and t is your clock's time
5. You are now rich! (The heat death of the universe must be far gone if gravity is zero, and so everyone else is dead, and so you possess all the money in the universe!)

[MHD]

1. measure length of feather
2. fix end of feather to a perfectly smooth rotation joint
3. apply known force for a known period of time to the other end of the feather
4. measure angular velocity
5. solve the regular rotational movement equations for mass

[WarDaft]

You know, some of these solutions would really take a while. We need something quick and easy.

Construct a frame holding up a 10 meter long bar of pure iron. Place the feather exactly 1 meter beneath the midpoint of the bar, and strike it with a 3 cm in diameter perfect iron sphere travelling at exactly 1 m/s. Now, move the feather 1 meter above the midpoint of the bar. Strike it again. The difference in tone due to tension will tell you the gravitational attraction the feather had on the bar, listen carefully and the rest is just a bit of math!

[Scyrus]

1. Acquire an average feather.
2. Weigh your housecat and count all of your cat's fur.
3. Have your cat eat the feather and place him in a box.
4. Wait an average ammount of time.
5. After that time, the cat may have or may not have expelled a furball.
6. Open the box and collapse logic the wavefunction.
7. Weigh the fur from the expelled ball.
7. Wait until your cat expells the ball.
7. Remove your dead kitten and get another.
8. Having the mass of the furball, place the furball in another box.
9. Open the door, get on the floor, everyone walk the dinosaur.
10. ????
11. Determine the mass of the feather.
12. ????
13. Profit.


What the f*** did I just read?

[KrO2]

What is the mass of a feather? How much do you want it to be?

Slice the feather into some number of pieces, being careful not to lose any. By conservation of mass, this pile has the same mass as the feather. Reassemble the pieces into exactly two (2) feathers identical to the original. The sum of the masses of these feathers must also be equal to the original.
Having proven that 1=2, you can now prove that the mass of the feather is whatever you want it to be.

[Copper Bezel]

Also, even finding an average feather is impossible with all the variation since the development of feathers (much of it uncertain in the fossil record), the difficulty of defining the first true feather, the fact that the sample size is dimishingly small over the age of the universe, and so on.

Perhaps it's the bias of my training, but rather than considering the feather as a physical phenomenon that is loosely defined and may or may not exist, I think it's more useful to consider the feather as a sociological phenomenon, a symbol or node of reference. We can't properly speak of the mass of a symbol, but we could consider the contexts, associations, and meanings associated with the appearance of the feather symbol and particularly the kinds of contexts in which the symbol can be expressed within a particular discourse community, all of which contribute to its weight. Necessarily, this would be unique to any particular social context, and no broad generalizations could be made across communities, since the feather as a sociological phenomenon is properly a characteristic of the society, rather than any transcending attribute of a proposed physical or formal "feather."

[Scyrus]

Do not try to weigh the feather. That's impossible. Instead, only try to realize the truth: there is no feather.

[Copper Bezel]

That's what I'm on about; I would tend to agree with you that there is no feather in an objective sense, but the very fact that we're having this conversation and being understood (that is, that "feather" evokes a lexical meaning) indicates that the feather does exist as a part of our subjective experience. Moving from there, so long as we are careful to accurately define the phenomenon we're concerned with, we can make objective claims about its existence and attributes, even regarding a subjective phenomenon. So to me, while a true statement, "There is no feather" still stops short of actually addressing the question.

[Scyrus]

But wouldn't that be true to any abstract concept? Any of those can be regarded as only existing subjectively.

If we can simply take this construct of the mind, this...feather, as you call it, you can launch from it an electron and measure its speed along the way*. Repeat until you determine the electron's escape velocity from said "feather". Solve for mass.
*MFW you can't measure both the position and the momentum of your subject.

[Xantix]

You guys are really going about this the hard way.

All you got to do is:
1. Isolate the average* feather**
2. Look up Wikipedia for the Mass of the Universe
3. Write that number down
4. Destroy*** the feather
5. Refresh the Wikipedia page to find the new Mass of the Universe
6. Subtract

*actually instead of taking the average, I recommend the median feather. Just go out, collect every feather, sort them by mass****, then choose the middle one.
**do the air molecules sticking onto the feather count as part of the feather? When does a feather stop being a feather? Are you my mummy?
***you have to completely destroy the feather. It can't leave residue, constituent particles, or anything. Don't give me any of that "Matter can't be destroyed, ..., blah blah blah." Rules were meant to be broken. Where there's a will there's a way. Never say never. Is the feather too 'scary' for you to destroy. Don't tell me you're chicken of feathers.

****to find their masses to compare them, just reapply this approach for each one.

Alternatively, just destroy all feathers in existence, including those abstract concept feathers mentioned above.

[Klear]

I think you are all missing the point of the original question. "What is the mass of a feather?" Surely, there are many easy ways to determine that, which leads me to believe the question is meant to be taken as rhetorical. Is there a reason to measure the mass of a feather? Should we measure it? Life is full of uncertainties and we struggle to make sense of it. But the act of measuring feathers will only leave us more vulnerable to the crushing despair that is inseparable from the human condition.

In short, about 0.15 grams.

[krogoth]

1.Design feather on computer.
2.Print feather on 3d printer.
3.Measure printing cartridge against full one.