Happy Drinking Dunking Bird Bobbing Head
Remember the great novelty toys of the '70's? Well one of them has made a COME-BACK and is just as popular as ever! The Drinking Bird has retained his youthful stamina for trying to quench his thirst, and is still just adorable! But this chickie isn't just for looks. OH, NO! He is actually a scientific wonder! He can be used in a classroom as a fun way to teach students about fluctuating temperatures caused by evaporation and condensation and its effects on motion. Get him started by dunking his head fully in a glass of water and soaking it well. Then sit him beside the glass so that as the water starts to evaporate from his head, it will change the temperature between the fluid in his head and the fluid in his tummy. The temperature change will then cause a pressure change in the fluid causing him to dip his head into the glass where it gets wet again, thus starting the whole thing all over.
How he works in more technical terms: As the water evaporates, it draws heat from inside the head. This causes the air within to cool and condense. The loss of heat and the reduction of air causes an imbalance of pressure between the head and tummy. The air in the tummy expands and pushes down to adjust for the loss of air in the head. This forces some of the liquid up the tube into the head, which reduces the amount of air in the head even more. At the same time, the pressure in the tummy decreases. This causes evaporation of the liquid which creates more air and increases the pressure in the tummy thereby causing more liquid to be forced up the tube and into the head. The rising liquid raises the center of mass of the bird to the point where the head can no longer stay upright and so it tips forward into the glass. The level of liquid in the bulbs has been set so that when the bird drinks, the bottom of the tube is exposed. The angle of the dip allowed by the pivot has been calculated so that a bubble of air can rise through the tube and allow the liquid to drain back into the tummy, which causes the bird to go back upright. The water from the re-wet head begins to evaporate again and re-starts the motion. A bit complicated for younger children to understand, but still lots of fun to watch! (Stands 7 tall on stand and 6 without stand.)
WARNING: This product is not a toy and is not intended for use by children under age 8. Use under adult supervision. Avoid breaking glass. Contains methelene choloride and may stain clothing and other surfaces. Do not swallow or allow to come into contact with eyes. Non-flammable. Keep away from flame and other heat sources.