The Drinking Bird
The Drinking Bird is a perfect example of the laws of thermodynamics. It works by having a liquid inside it with a very low boiling point.
How the Drinking Bird works
To start the bird off you dip its head in water. This wets the material surrounding the head and you stand the bird upright. Over the course of a few minutes the water will start to evaporate off the birds head, this causes the top section of the bird to cool (this is also the reason why we sweat).
As the upper section cools this causes the air inside the upper bulb to cool, if you cool a gas in contracts, this contraction creates a partial vacuum inside the top section and as a result the liquid is “sucked” upwards towards upper section.
As the liquid travels upwards through the central tube it passes the point at which the bird is balanced upon, when it reaches and passes here the bird tips over and dips its head in the water again. This causes the upper section to get an increase in temperature, the liquid shoots back down the tube and the bird stands upright again, pretty cool huh? If you don’t understand how the drinking bird works yet don’t worry, Albert Einstein couldn’t figure out how they worked. You’ll get it after seeing one working for a few minutes.