What is the mass of a feather?

[Sana]

It's for science.

[Infornographer]

I would put it on the order of 1 gram.

[Mathmagic]

Depends on how big the feather is?

[Sana]

I would put it on the order of 1 gram.

Thanks.

Depends on how big the feather is?

Just on average. An average feather from an average bird. Whatever that is.

[po2141]

Just on average. An average feather from an average bird. Whatever that is.

Exactly one few grams.

[evilbeanfiend]

if it for science then might i suggest using science to find out. what experiment can you perform to find out?

[Mathmagic]

if it for science then might i suggest using science to find out. what experiment can you perform to find out?

You're not suggesting he/she actually weighs the feather, are you? Because that would be absolutely ridiculous.

Should this thread be put in logic puzzles?

[22/7]

Why shouldn't she weigh the feather?

[nilkemorya]

No, you don't weigh the feather...that would be ridiculous, as you would be determining the weight of the feather there. I would assume he is suggesting that you apply a known force to a feather and measure the acceleration, thus determining the mass.

[gmalivuk]

It's for science.

One featherweight, obviously. So, all we can be sure of is that it's under 126 pounds.

[Robin S]

apply a known force to a feather and measure the acceleration, thus determining the mass.

Air resistance can, of course, be neglected.

[nilkemorya]

No no no no...neglecting air resistance would be super bad. I said a known force. If you have air resistance, unless you can somehow precisely determine it, you'd have an unknown force. I would suggest doing it in a vacuum, probably in microgravity. That way you could just set up some kind of force application system like a laser beam to make it work. Of course, measuring the exact acceleration would be difficult, but I would guess you could cheat by setting up your experiment far away from other gravitating and light emitting bodies, and then apply said laser push over a long period of time, measuring the velocity. Don't forget to take the gravitational effect of your laser/measurement system into account though. I think you could fairly reasonably determine it's mass that way, for certain definitions of reasonable.

[Herman]

Make an identical feather out of antimatter. Collide inside thick shell of lead surrounded by vacuum. After a long time (but not too long!) measure the change in temperature of the shell. Add E = mcc, stir.

[tel]

Don't forget to take the gravitational effect of your laser/measurement system into account though.

Yeah, and if the feather rotates at all don't forget the geodetic and frame dragging forces either. Also be sure to renormalize its quarks.

I dunno, it seems like if you just put the feather on a triple beam balance and then put a weighing boat on top of it you would get a result for the mass that, although it would have orders of magnitude fewer significant digits than the answer produced by Nilk's most excellent and refined approach, would probably be good enough for science.

[Sana]

Why shouldn't she weigh the feather?

Because then I would have to weigh Thalassa.

[evilbeanfiend]

simply get some antimatter and see how much it takes to annihilate the feather, remember to keep track of the signs in your equations!

[Citizen K]

What is the mass of a feather?

In ancient Egypt...
One soul, more or less.

And I remember some reading about some scientist or another who once tried to weigh souls as they escaped dying people (don't remember all the details offhand). So find those numbers and use them. Or go collect your own data. "Now hold still. Remember, it's for science."

[ArmonSore]

But once you accelerate it to a new velocity the mass changes

[Robin S]

I would assume we are talking about rest mass at absolute zero.

[ATCG]

And I remember some reading about some scientist or another who once tried to weigh souls as they escaped dying people (don't remember all the details offhand). So find those numbers and use them. Or go collect your own data. "Now hold still. Remember, it's for science."

Thanks to the astonishing advances of science, we now know that the mass of the human soul is 28 grams - a figure definitive enough to base a movie title on. Aren't we fortunate to live in an age where this need no longer be a matter of guesswork?

[sgt york]

I would suggest doing it in a vacuum, probably in microgravity. That way you could just set up some kind of force application system like a laser beam to make it work ... apply said laser push over a long period of time, measuring the velocity. Don't forget to take the gravitational effect of your laser/measurement system into account though.

Also, be sure to take into account the absorbance and emission spectra of the compounds the the feather, as well as the efficiency of that transfer. You will not only have to take the loss of efficiency in acceleration, but the opposing accelerative forces as energy is radiated away. These may cancel out, as the radiative energy should be equal in all directions, but this may vary with the geometry of the feather.


Also, as you will be applying a significant force over a period of time, be sure to take relativity into account. Of course you'd take the mass effect into account, but you'd be surprised how many people neglect time dilation and its effects on measured velocity (distance/time).

[0SpinBoson]

I say he weighs 1000 feathers and divide.

[ATCG]

Record your weight on bathroom scale. Record your weight on bathroom scale holding feather. Subtract.

[McHell]

Thanks to the astonishing advances of science, we now know that the mass of the human soul is 28 grams

Correction, that's 21 grams. Anyways, this type of sciencing also alledgedly showed travel above 20mph to be deadly for lack of oxygen.

For what it's worth, 1 gram for a feather sounds far to much. As in, more than an order of magnitude. Consider that a falcon weighs something like 150--200gr and has some about as many (sizeable, force-bearing, not downy) feathers. You see, most mass is in the body so the feathers must be less.
1gr would be the weight of a 1cm cube of water --- pigeon's feathers have clearly less volume and are also known to float (that may be due to the hollow shafts though).

Measuring wouldn't be such a bad idea, enough precision balances lying around.

[ATCG]

Thanks to the astonishing advances of science, we now know that the mass of the human soul is 28 grams

Correction, that's 21 grams.

Dang. You're right. That means I have years of scientific research to redo.

[zenten]

But once you accelerate it to a new velocity the mass changes

That depends on your reference frame.

And generally feathers are always accelerating. Unless they're in free fall in a vacuum.

[Robin S]

But once you accelerate it to a new velocity the mass changes

That depends on your reference frame.

Does it? I thought acceleration always affected mass, regardless of reference frame (unless the reference frame was accelerating with the feather, which I gathered it wasn't from the phrase "new velocity").

[ArmonSore]

I would assume we are talking about rest mass at absolute zero.

But absolute zero is impossible under the heisenberg uncertainty principle. [citation needed]

And as Robin stated, in what reference frame doesn't the mass change when the speed changes?

[Robin S]

But absolute zero is impossible under the heisenberg uncertainty principle.

Yes, it's impossible to actually achieve, but you can find the limit of the feather's mass as it approaches absolute zero.

[ArmonSore]

But absolute zero is impossible under the heisenberg uncertainty principle.

Yes, it's impossible to actually achieve, but you can find the limit of the feather's mass as it approaches absolute zero.

Well.... by the time energy uncertainty princple and E = mc^2, we can't even do that unless we wait an infinite amount of time!

[Robin S]

You can find it to an arbitrary degree of precision within finite time, which is good enough for pretty much all purposes.

[ArmonSore]

Well, if you only want the "practical" mass of a feather then you don't have to worry at all about the weird things that happen when you start to ask for something "exactly".

For example, I could ask you "what do you mean by feather"? And you show me a bird's feather. But on a microscopic level how do we know which molecules are feather and which molecules are air? What about the dirt on the feather which is constantly accruing and leaving?

[evilbeanfiend]

obviously you use a standardized feather

[Robin S]

Which would, as a mass standard, presumably be made of a platinum-iridium alloy.

[OneLess]

No, you don't weigh the feather...that would be ridiculous, as you would be determining the weight of the feather there. I would assume he is suggesting that you apply a known force to a feather and measure the acceleration, thus determining the mass.

Or perhaps put the feather in a gravitational field so that acceleration is known, and measure the force applied to an instrument that can measure it

[zenten]

But once you accelerate it to a new velocity the mass changes

That depends on your reference frame.

Does it? I thought acceleration always affected mass, regardless of reference frame (unless the reference frame was accelerating with the feather, which I gathered it wasn't from the phrase "new velocity").

Oh, maybe I misunderstood what was said. I thought you were talking about taking an object, accelerating it to a new velocity, and then you stop accelerating it, at the new velocity.

[Robin S]

I was talking about that. Under what circumstances would changing the velocity relative to your reference frame not affect mass?

[ArmonSore]

No, you don't weigh the feather...that would be ridiculous, as you would be determining the weight of the feather there. I would assume he is suggesting that you apply a known force to a feather and measure the acceleration, thus determining the mass.

Or perhaps put the feather in a gravitational field so that acceleration is known, and measure the force applied to an instrument that can measure it

Except that you'd need to know the position of the feather and the earth exactly. So we're right back at the heisenberg uncertainty principle. And how would you measure the force? By looking at the deflection of a spring? That would require measuring another distance exactly.

obviously you use a standardized feather

The definition of a "standardized" feather would be even more dubious than the definition of a "feather".

[gmalivuk]

The definition of a "standardized" feather would be even more dubious than the definition of a "feather".

Nah. Just define a standard feather to have a mass equal to, say, 1000000000000000000000 silicon-28 atoms. Then, when the new standard kg is produced, and they know how many atoms are in it, we'll know exactly what mass a standard feather has.

[stockpot]

When I placed a lovebird (Agapornis roseicollis) primary flight feather on a standard electronic postage scale, the scale displayed the value "0 g."

Thus all feathers are, in fact, massless.