Drinkvogelfantopic deel I

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Drinking birds, also known as dippy birds and dipping birds,[1] are toy heat engines that mimic the motions of a bird drinking from a fountain or other water source. It is sometimes incorrectly considered a perpetual motion device.

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The drinking bird is a heat engine that exploits a temperature differential to convert heat energy to a pressure differential within the device, and perform mechanical work. Like all heat engines, the drinking bird works through a thermodynamic cycle. The initial state of the system is a bird with a wet head oriented vertically with an initial oscillation on its pivot.

The process operates as follows[2]:

1. The water evaporates from the felt on the head.
2. Evaporation lowers the temperature of the glass head (heat of vaporization).
3. The temperature's drop causes some of the dichloromethane vapor in the head to condense.
4. The lower temperature and condensation together cause the pressure to drop in the head (ideal gas law).
5. The pressure differential between the head and base causes the liquid to be pushed up from the base.
6. As liquid flows into the head, the bird becomes top heavy and tips over during its oscillations.
7. When the bird tips over, the bottom end of the neck tube rises above the surface of the liquid.
8. A bubble of vapor rises up the tube through this gap, displacing liquid as it goes.
9. Liquid flows back to the bottom bulb (the toy is so designed that when it has tipped over the neck's tilt allows this), and vapor pressure equalizes between the top and bottom bulbs
10. The weight of the liquid in the bottom bulb restores the bird to its vertical position
11. The liquid in the bottom bulb is heated by ambient air, which is at a temperature slightly higher than the temperature of the bird's head.

If a glass of water is placed so that the beak dips into it on its descent, the bird will continue to absorb water and the cycle will continue as long as there is enough water in the glass to keep the head wet. However, the bird will continue to dip even without a source of water, as long as the head is wet, or as long as a temperature differential is maintained between the head and body. This differential can be generated without evaporative cooling in the head—for instance, a heat source directed at the bottom bulb will create a pressure differential between top and bottom that will drive the engine. The ultimate source of energy is the temperature gradient between the toy and the surrounding environment—the toy is not a perpetual motion machine.

A recent analysis [3] showed that the evaporative heat flux driving a small bird was about 0.5 W, whereas the mechanical power expressed in its motion was about 50 microwatts, or a total system efficiency of about 0.01%. More practically, about 1 microwatt can be extracted from the bird, either with a coil/magnet or a ratchet used to winch paperclips.

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Op vrijdag 20 augustus 2010 12:19 schreef Rectum het volgende:
Waar heb je dat ding gekocht?

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Op vrijdag 20 augustus 2010 12:25 schreef Patje1987 het volgende:

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10 besteld

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Op vrijdag 20 augustus 2010 12:26 schreef SuperFokker het volgende:
Kun je die ook in Nederland bestellen?

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Op vrijdag 20 augustus 2010 12:36 schreef SuperFokker het volgende:

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jama ik heb geen creditcard...en met paypal moet je weer ff wachten om dat te activeren :p
Ik wil al snel naar mijn drinkvogel kunnen kijken..heb vakantie...dus dan kan ik hele dagen daar naar kijken.
Heb toch geen sociaal leven

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Op vrijdag 20 augustus 2010 12:38 schreef preutest het volgende:
Terechte klacht

Kan je daar dan zelf vloeistof in doen of is dat een speciale soort vloeistof?

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Op vrijdag 20 augustus 2010 12:40 schreef Patje1987 het volgende:

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Ook zijn de oudere versies kankerverwekkend, gelukkig hebben ze dit opgelost!

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Op vrijdag 20 augustus 2010 12:45 schreef preutest het volgende:

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SPOILER

Om spoilers te kunnen lezen moet je zijn ingelogd. Je moet je daarvoor eerst gratis Registreren. Ook kun je spoilers niet lezen als je een ban hebt.

Gast

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Op vrijdag 20 augustus 2010 12:49 schreef Rectum het volgende:
Werken die dingen ook met gewoon kraanwater?

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Op vrijdag 20 augustus 2010 13:30 schreef Agiath het volgende:
Wel grappig, het is nog best een aardige cyclus wat zo'n ding maakt

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Op zaterdag 21 augustus 2010 01:00 schreef Drinky het volgende:
Ik dacht naamtopic

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Op zaterdag 21 augustus 2010 10:42 schreef drummerdude het volgende:
Gister besteld, kan nu al niet wachten! Heldending!