Comments on: Brain Game. The Flying Hummingbird

By: Brain Game. Matches | Mental Beauty

Brain Game. Matches | Mental Beauty — Thu, 04 Sep 2008 23:26:22 +0000

[...] here’s the answer to the previous brain game about the flying hummingbird. It was given by Chris – a very good explanation: if the hummingbird weighs 1 gram, the scales will [...]

By: Geniusbeauty.com

Geniusbeauty.com — Tue, 03 Jun 2008 12:59:23 +0000

Jed, and if not?

By: Chris

Chris — Tue, 03 Jun 2008 12:54:13 +0000

OK. Let’s say the hummingbird weighs (for arguments sake) one gram. The scales will show one gram. As the bird starts to fly the scales will show slightly more than one gram as energy is used to hop (kinetic energy) into flight giving the bird potential energy. As the bird is flying the scales will read one gram since an equilibrium situation between downward thrust of the air having to match the weight of the bird has been reached. As the bird lands the scales will read slightly more than one gram due to the potential energy being turned into kinetic energy and that kinetic energy being dissipated as landing happens. The bird having landed the scales will revert to one gram.

By: Jed

Jed — Tue, 03 Jun 2008 08:39:52 +0000

Is the cover air tight on top of the scales?

If it is, the net change will be nil. (May or may not be true I stopped doing science years ago :p)

By: Geniusbeauty.com

Geniusbeauty.com — Mon, 02 Jun 2008 19:00:11 +0000

Please, describe more detailed, what will the scales show, when the bird starts to fly, is flying and lands back onto the scales (everything under that cover, of course).

By: Chris

Chris — Mon, 02 Jun 2008 06:03:42 +0000

I have to agree with Pete. Nothing will change in a closed system. The hummingbird apparently weighs (typicially) one one fourteenth of an ounce. They are called hummingbirds because they forgot the words.

By: Jed

Jed — Thu, 29 May 2008 21:40:42 +0000

That’s right, wilottica, I think there must be a clue somewhere which turns it into a riddle from being a physics problem.

Physics: the bird would disturb the scales to a strange effect of fluctuating vividly.

Then there’s a film, wihch states that you lose 21 grams when you die, which they claim is the weight of a hummingbird (but that’s very inaccurate, they weight less than 3 grams normally).

By: scott

scott — Thu, 29 May 2008 17:57:18 +0000

This was done on Mythbusters.
Essentialy air is a fluid like water. When a bird flys it is basicaly swimming in the air no different that if a large fish were sleeping at the bottom of a fish tank and then started to swim.
The weight in the beginning is transfered directly to the scale as then as the bird flys the weight is transfered to the air, which in turn transfers the weight(force) to the scale.

So the Scale might fluctuate a little as the bird flys but if you average it out over even a couple seconds of time it will equal the weight of the bird.

My 3cents

By: Gary Crowningshield

Gary Crowningshield — Thu, 29 May 2008 16:05:54 +0000

The reading on the scales would remain the same when the bird is flying as when the bird is asleep. That is because the downward force of air caused by the birds flapping wings is approximately the same as its weight. This downward force causes pressure on the scale approximately equal to the bird’s weight.

By: willottica

willottica — Thu, 29 May 2008 15:19:39 +0000

Hmm… I read this as meaning that there is a scale which has a covered hummingbird on it, in which case it becomes an interesting physics problem rather than a riddle.

To solve, I used the assumption that the sleeping bird and the cover were both currently being weighed… then followed with the assumption that the bird would not upset the cover when it started to fly.

Generally, I think more information is required, because many assumptions have to be made to come up with an answer (whether it’s a riddle or a physics problem).

By: Pete

Pete — Thu, 29 May 2008 14:52:58 +0000

Be clever people.
The scale registers the weight of the bird (who cares how much he weighs!) and the weight of the cover (who cares what it’s like?) When the hummingbird takes off (and no, they don’t fly backwards as a rule.) the scale will register the weight of the cover and the weight of the bird as usual. He is off the scales but he is thrusting air down at the scales with the same force that keeps him aloft. Net zero change. L. Watts, I guess you got it.

By: L. Watts

L. Watts — Thu, 29 May 2008 14:35:01 +0000

Nothing should happen when the hummingbird wakes up and starts flying. The bird is not on the scales, just under the cover with the scales.

By: Geniusbeauty.com

Geniusbeauty.com — Wed, 21 May 2008 18:14:22 +0000

Jed, here are the answers:

>Would the cover’s weight be negligible?
It can be any weight, no matter, what.

>What about the bird’s ability to lift the cover away?
Let’s say, the cover weights more, than the bird.

>Is the cover a piece of light cloth?
The cover can be even plastic, it’s not important, what the cover is made of. And the shape of the cover doesn’t matter.

>What do the scales indicate while the hummingbird is still sleeping?
It can be whatever weight, it’s not important.

I hope, my answers were clear enough and will help you solve the riddle.

By: Jed

Jed — Wed, 21 May 2008 15:31:09 +0000

An interesting riddle, indeed. One that I don’t understand, much at all.

A hummingbird would be very light, and flies backwards.
Would the cover’s weight be negligible?
What about the bird’s ability to lift the cover away?

Is the cover a piece of light cloth?

What do the scales indicate while the hummingbird is still sleeping?