Three main principles of physics keep this bird drinking almost forever. Evaporative cooling, Boyle's gas laws, and gravity. Can you explain them all?
Here is how the Drinking Bird works:
- Get your Drinking Bird's beak wet in a glass of water, and let it sit back up.
- When liquid evaporates from the Drinking Bird's fuzzy head, the head cools down, which condenses the vapor inside, decreasing the pressure in the head relative to the vapor in the birds belly.
- The greater vapor pressure in the belly forces fluid up through the neck and into the head.
- As fluid enters the head, it makes the Drinking Bird top-heavy.
- Now the Drinking Bird get's thirsty. Liquid travels to the head. The bottom of the tube is no longer submerged in liquid.
- Vapor bubbles travel through the tube and into the head. Liquid drains from the head, displaced by the bubbles.
- Fluid drains back into the belly, making the bird bottom-heavy.
- The Drinking Bird tips back up, and the process lasts as long as the bird can dip its head into water.
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