Drinking Bird
Equipment: A 'drinking bird' and a glass of water. Optional: a plexiglass box and a squeeze bottle containing alcohol.
What it does: The bird bobs forward into the glass of water and recovers. It oscillates in the upright position for a few moments before bobbing into the water once more. It repeats this motion until no more water is available.
Concepts Demonstrated: Cooling by evaporation; heat engine; relaxation oscillator.
Classroom assembly:
- Wet the bird's head.
- Place the bird next to the glass of water. The bird will begin to bob and oscillate.
Optional
- Place the plexiglass box over the bird. The evaporation will slow enough to stop the bobbing.
- Squirt alcohol on the bird's head.
- Replace the box. The bird will begin to bob again as the alcohol speeds up evaporation.
Cautions: The drinking bird is fragile. Handle with care.
Setup Time: Short.
Difficulty: Straightforward.
Visibility: Medium. The aparatus is small but the motion of the bird is visible in a large lecture hall. The video camera can be used for extra clarity.
Related demonstrations:
References: PIRA 4C31.30
Video Encyclopedia 15-12
Original Construction: Purchased.
Disclaimer: All demonstrations are posted for the convenience and benefit of faculty and staff in the Department of Physics at Simon Fraser University and are not intended for outside use. The author(s) assume no responsibility or liability for the use of information contained on this site. Warnings and precautionary measures listed on this site assume normal operation of equipment and are not inclusive. Demonstrations may pose a significant hazard and can, in some instances, result in death; reasonable safety precautions must be taken. Demonstrations should be performed by qualified individuals only.
Prepared by Jeff Rudd, 1999
Revised by Laura Schmidt, June 2007