Perpetual motion drinking bird

[dichotomy]

What scale would a ‘drinking bird toy’, or, ‘dinky bird’, need to be in order for it to fully power a low voltage 20w light bulb. I’d imagine it would produce power by moving some type of dynamo of your choice?

 

Any takers on this hair brain idea?

 

cheers.

[Klaynos]

if you added in a dynamo it would significantly dampen the ocilation and therefore the bird would not carry on moving for very long at all...

 

Which is why we wind up clocks and don't just put a dynomo in with the pendulum and use it as a duel purpose...

[Fuzzwood]

The moment you add some type of energy conversion, the energy will be converted and will get less over time

 

/me smacks a few kittens with Newton's 1st law of physics.

[swansont]

The moment you add some type of energy conversion, the energy will be converted and will get less over time

 

/me smacks a few kittens with Newton's 1st law of physics.

 

The energy won't "get less over time" — you aren't depleting an energy reservoir. The drinking bird works because it's not an isolated system. It's just that the energy transfer in evaporative cooling isn't going to drive a very big system.

 

http://www.exploratorium.edu/snacks/dippingbird/index.html

"Don rathjen has measured the power output of a dipping bird by attaching it to a windlass and using it to raise paper clips. He managed to extract a nanohorsepower of work from his dipping duck. (A nano-horsepower is about a microwatt.)"

 

edit: here's a non-evaporative, direct-solar variant http://scitoys.com/scitoys/scitoys/thermo/solar_bird/bird.html

[dichotomy]

edit: here's a non-evaporative, direct-solar variant http://scitoys.com/scitoys/scitoys/thermo/solar_bird/bird.html

 

Clever! Now I know what to do with my drinking bird when the fuzz falls off.

 

if you added in a dynamo it would significantly dampen the ocilation and therefore the bird would not carry on moving for very long at all...

 

This is why I stated what sort of scaled up version would be required. Would the bird need to be scaled up to the size of an ostrich? or the size of the Eiffel tower? Drinking birds are about 100mm long.

The dynamo could be one like the type that was commonly available for bicycles at one stage.

 

cheers.