Soda Lime and Sulfur Dioxide
A large beaker contains a covered vial of soda lime, which is a damp mixture of sodium hydroxide and calcium oxide. Sulfur dioxide gas is added to the beaker and the top of the beaker is sealed with a rubber dam. The vial is tipped over, so the soda lime can mix with the sulfur dioxide. The reaction of the calcium oxide with sulfur dioxide creates solid calcium sulfite, decreasing the number of gas particles and thus the pressure within the beaker, so the dam is pushed inward by atmospheric pressure.
The size of the movie file is 4.1 MB and its duration is 60 seconds. The name of the movie file is "SO2PR4.MOV" and it is located in the folder "MOVIES/SO2PROP".
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