Drinking Bird, 4C31.30

Location:

• Cabinet: [:ThermoCabinet:Thermodynamics Cabinet]

• Bay: [:ThermoCabinetBayA2:A2]

• Shelf: #5

(attachment photo showing the fully set up demonstration)

Description: Also called Dippy Bird or Tippy Bird.

Setup:

1. Set up like picture above.
2. Make the felt of bird wet.
3. Wait until you see the red liquid grow up.

Cautions, Warnings, or Safety Concerns:

Demonstration:

Put water on the felt of bird. When water evaporates, it makes the temperature of the glass head lower. This makes some of the dichloromethane(red liquid)vapor to condense. From ideal gas law, the pressure in the head of the bird drop due to the lower temperature and condensation. The difference of the pressure between the head and base of the bird causes the red liquid to be pushed up from the base. Then the head of the bird become heavy and tips over. While the bird tips over, it make air hole that can make red liquid flows back to the bottom bulb and this makes bird go back to its vertical position again. And this will occur periodically until the water on the felt of bird dry.

References:

1. http://en.wikipedia.org/wiki/Drinking_bird

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