Source: Sixty Symbols. Type keyword s to search. Today's Top Stories. Sixty Symbols YouTube. Armed with a thermal imaging camera, Brady Haran of Sixty Symbols decided to take a closer look at the classic toy to reveal its inner workings : This content is imported from YouTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site. An essential requirement to make the bird dip is to get the head cooler than the body.
Normally this is accomplished by water evaporating from the head. By painting the body black and exposing the bird to a hot lamp or to sunlight, the body will become warmer than the head. In this way, you can either enhance the normal operation of the bird or get it to operate without wetting the head at all.
Attribution: Exploratorium Teacher Institute. Connect with us! Get at-home activities and learning tools delivered straight to your inbox. The Exploratorium is a c 3 nonprofit organization. Dipping Bird A dipping bird seems to go forever—but it's not perpetual motion. Grade Bands:. Two equal-sized, hollow glass bulbs A long glass tube that connects the bulbs Fuzzy, water-absorbent material covering the head Two plastic legs with a pivot connection Methylene chloride in the abdomen.
Methylene chloride is an industrial paint stripper and solvent one thing that dissolves easily in methylene chloride is caffeine, so you can use methylene chloride to decaffeinate things -- see Question Methylene chloride helps makes a Dippy Bird work because it evaporates very easily -- it boils at just degrees Fahrenheit 40 degrees Celsius.
When water evaporates from the fuzz on the Dippy Bird's head, the head is cooled. The temperature decrease in the head condenses the methylene chloride vapor, decreasing the vapor pressure in the head relative to the vapor pressure in the abdomen. The greater vapor pressure in the abdomen forces fluid up through the neck and into the head.
As fluid enters the head, it makes the Dippy Bird top-heavy. The bird tips. 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. This is the most crucial point in understanding how the drinking bird works. If you could cool the head another way, the drinking bird would work just the same.
When the head begins to cool, some of the vapor within the head will condense into tiny droplets of liquid. A similar process occurs at night when water vapor condenses out of the air as it cools, forming dew on the ground. Because some of the vapor condenses within the top chamber of the bird, there is now less vapor pressure in the top bulb. Less vapor means less pressure. But the vapor pressure within the bottom bulb has not changed. Because the vapor pressure in the bottom bulb is now greater than the pressure in the top bulb, the liquid is forced upward into the top chamber.
Once the bird tips over, vapor from the bottom travels to the top until the pressure in both spheres equalizes and the bird begins the process all over again. To understand how a pressure differential causes fluid within the bird to rise, consider what happens when you use an ordinary drinking straw. When you suck fluid up into the straw, you create a region of reduced pressure within the straw.
Because outside air pressure is greater, it pushes downward on the surface of the fluid, forcing it upward. Not only is the drinking bird educational, but it can also provide hours of entertainment.
Many science museums feature displays of drinking birds. No science classroom would be complete without one. The amazing drinking bird has even appeared in a episode of The Simpsons, where Homer positions a drinking bird in front of his keyboard to help monitor the controls at the Springfield nuclear power plant. They had to be made with a special vacuum attachment in order to work properly. There are many variations on the drinking bird. They come in a variety of styles and sizes.
There is even a drinking giraffe!
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