The dancing of a coin on a frozen bottle and its evolution
Abstract
When putting a coin on the mouth of a frozen bottle, over time one will hear a sound and see movements of the coin. Different methods are utilized to observe this phenomenon and obtain experimental data. A theoretical model is established and the dependence of air pressure and the variation of angle on time is acquired for a single movement, which is consistent with the experimental results. Other important observables are also discussed, such as the waiting time between two adjacent dances and the total dancing times. It is concluded that the greater the ratio of side area to volume of the bottle, the more frequently the coin can dance; and the greater the initial temperature difference, the more frequently it will dance. It is believed that this topic is well adapted for class teaching including demonstration, observation and verification because of its attraction as a phenomenon, low equipment requirements and the interesting mechanism behind it.
- Publication:
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European Journal of Physics
- Pub Date:
- March 2020
- DOI:
- 10.1088/1361-6404/ab61c3
- Bibcode:
- 2020EJPh...41b5105L
- Keywords:
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- ideal gas law;
- thermal expansion and contraction;
- heat transfer