Is a box full of flying canaries lighter than a box ful of perched canaries.?

Answer 1

No unless the sides or bottom of the box allows egress of downward flowing air that the canaries generate from their flight. Otherwise the air flows within the box will generate forces on the box equivalent to the weight of the birds.

Answer 2

They both have the same mass.

For example, a football on the ground compared to a football in the air... either way, its still a football and it has the same mass either way. Just because a bird is flying doesn't effect the mass.

However, if the birds are in a big box and are not touching any of the sides or bottom, the weight of the birds will not add to the weight of the box. In this case, yes its lighter. However, if the box is perfectly sealed... meaning that its air tight, the downward force of the air exerted by the wings of the birds will equal to the weight of the birds. In order for the birds to stay levitated, the downward force (gravity) must equal the upward force (wings of the bird blowing air down as it pushes the bird up). So if theres no air escaping, then no, they both weigh the same

Answer 3

Are you trying to air mail a box of birds? ;-)

But wait, wouldn't an airtight box suffocate the birds, making their flight impossible?

If you want to find out, try putting air-filled [not empty] balloons into a box, weighing it, and then fill the same balloons with helium & place them back into the box before weighing it again, and see what happens (Dang it! My suggested experiment will be slightly off due to the fact that the inflated balloons will touch the top of the box, thereby making the box itself buoyant!).

**BTW, this is my own personal opinion as a private individual; I am not representing the Patent & Trademark Office in any way with this posted comment.

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Correction to my earlier comment [which I deleted because it was incorrect].

After consulting with my co-workers about your hypothetical problem, we came to the conclusion that if it is a sealed box, then the weight of the bird plus the box should weigh the same irregardless of whether the bird is flying or not, due to the Law of the Conversation of Energy. The downdraft from the bird's wings should place weight on the box (the counter-force of the updraft would only affect the bird, not the box top -- so even though the bird is hovering, he is pushing on the air which in turn pushes down on the box).

So a box of flying birds should WEIGH THE EXACT SAME as a box of resting birds -- at least acording to several of us at the U.S. Patent Office (three Electrical Engineers plus one person with a B.S. in Physics).

---edit2---

Try my above suggested experiment with a radio controlled model helicopter in a hermetically sealed box. The box has to be AIR TIGHT. We believe that you should notice no change in weight reading on the scale whether the aircraft is hovering or not, due to the downdraft from the helicopter pushing air downward on the box bottom (the counter-force from the updraft is supporting the weight of the helicopter, not the box top).

Like "m.paley" said below, if the box is not sealed, then some of the downdraft will blow out the sides of the box, making the box slightly lighter instead.

Try sending an e-mail to "MythBusters" and see if they will try this on TV. ^_^

Answer 4

Possibly. If the downward wind from the canaries wings is blowing out through the sides of the cage then the entire thing will be fractionally lighter. If the wind is just hitting the base of the cage then it will weigh the same.

Answer 5

You would think yes because the aviation of flight defies the weight of the birds in relation to their mass. But really they are fighting against the force of gravity therefore their supposed weight appears less although the pull of gravity on the weight of the bird (mass)should be the same if it is sitting still anywhere or flying.

Answer 6

Yes, because when they are flying they are exerting no downwards force on the box so the whole thing is lighter

Answer 7

yes since flying means they are supporting themselves and not xsfering weight to the box

Answer 8

Yes as long as the box is not hermetically sealed

Answer 9

yes you have got the weight of the birds and the weight of the perches duhhhhh

Answer 10

The mass is the same, the weight will be different