Bird in a box

[Bigtallfatbloke]

A cat would solve this problem faster!

 

[bonj2]

No it doesn't. You misunderstand. As Patrick said, under certain conditions the flying bird would exert force on the bottom of the box.

I was understanding it to be a cardboard box, into which air can flow through the flaps. Is it not in fact a cardboard box?

 

[Cycling Naturalist]

So - when the lid is closed, the scales will measure the both the bird and the box, irrespective of if it is flying or not(mass or weight, bonj - I know the difference, and it doesn't matter in this case (I think lol))

But what happens when the lid is opened, but the bird is still flying in the box ? (Hummingbird is better than canary)

Andrew

It's no longer a closed system where the forces balance out and the bird's weight will appear to vary depending on a set of parameters including the following, air temperature, size of box and height of bird above box floor.

 

[mosschops2]

1010g, lid shut, canary standing. Fine

When the canary is hovering / flying in circles, the box will weigh in at 1000g, and the slight force on the air on the scales will register also - like when you get lab scales - even breathing can affect the reading. But it will be 1000g plus a tiny amount - say 1001g +/- 1 g.
(ie not 1009g +/- 1g)

 

[Cycling Naturalist]

1010g, lid shut, canary standing. Fine

When the canary is hovering / flying in circles, the box will weigh in at 1000g, and the slight force on the air on the scales will register also - like when you get lab scales - even breathing can affect the reading. But it will be 1000g plus a tiny amount - say 1001g +/- 1 g.
(ie not 1009g +/- 1g)

If you had a hummingbird in a minute box it would appear to weigh heavier than when it is in a large box because there would be a greater volume of air to absorb the downforce from its wings.

One interesting factor is that the box would heat up. I'll let bonj explain why.

 

[Elmer Fudd]

One interesting factor is that the box would heat up. I'll let bonj explain why.

Friction (wings against air).
Plus the ickle canary is warm blooded .

As an aside, I've just let our two lovebirds out of their cage. The house still weighs the same

 

[Cab]

What if there is a vial of poison and some radioactive substance in there?

 

[Cycling Naturalist]

One interesting factor is that the box would heat up. I'll let bonj explain why.

Friction (wings against air).
Plus the ickle canary is warm blooded .

[/QUOTE]

Yes, and as the air loses the energy that had caused it to move, it releases it as heat.

 

[bonj2]

Hmmm... you've got to think outside the box for this one.
Why do you think it would heat up Patrick? I'm not sure it would, although will listen to your reasoning with an open mind if you think it would...I suppose there would be friction between its wings and the air but that would be miniscule/insignificant to the actual box itself.

OK, here's another conundrum. (I know the answer to this.) Given that mosschops is right that the reading on the scales would be, say, 1001g +/- 1g, which I think he is, then how would you determine the (fairly) exact mass of the bird WITHOUT unsealing the box?
By unsealing it I mean rendering it a non-closed system, i.e. the air inside it is just part of the atmosphere.

 

[alecstilleyedye]

what about a bumblebee, which apparently obeys none of the principle laws of aerodynamic flight?

 

[chris42]

My "bird" won't get into a box so I can't try!?
She says its not normal

 

[Tetedelacourse]

Threaten to get into her box if she resists.

 

[Cycling Naturalist]

Hmmm... you've got to think outside the box for this one.
Why do you think it would heat up Patrick? I'm not sure it would, although will listen to your reasoning with an open mind if you think it would...I suppose there would be friction between its wings and the air but that would be miniscule/insignificant to the actual box itself.

OK, here's another conundrum. (I know the answer to this.) Given that mosschops is right that the reading on the scales would be, say, 1001g +/- 1g, which I think he is, then how would you determine the (fairly) exact mass of the bird WITHOUT unsealing the box?
By unsealing it I mean rendering it a non-closed system, i.e. the air inside it is just part of the atmosphere.

The bird is warm blooded and gives off heat.

The answer to the conundrum is to monitor the weight of the box and bird over a 24 hour period and take the highest weight and subtract that of the box. The bird would have to rest on the floor of the box at some time within the 24 hours and that would give the maximum reading.

 

[mosschops2]

Except that if the bird were to "jump" (lol) onto the floor, the reading would peak, then settle....

 

[chris42]

if all the birds jumped at the same time would there be a tidel wave somewhere?