Changes in pressure after the foam disappears in a sealed container
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Water is added to a beaker, a certain substance is poured in and stirred; this results in the formation of many bubbles. Once the substance has dissolved completely, the beaker is sealed with plastic wrap. After some time, it is observed that the plastic wrap on the beaker collapses and the foam disappears. Comparative experiments were conducted using different batches of the same substance, and hardly any foam was produced in those beakers, so the plastic wrap did not collapse after sealing. I would like to ask everyone what might be the reasons for the collapse of the plastic wrap.
If there is no foam in other batches, does that mean the batches with foam have poor quality?
It’s possible, but why does the plastic wrap collapse when the foam disappears?
If the plastic wrap sags, it means the pressure inside has decreased. Can these agents absorb oxygen?
The cause of the collapse might not be the foam, but rather the temperature. The bottle that produces foam has a higher temperature than the other cups; once the temperature returns to normal, the pressure inside the plastic wrap decreases, causing it to collapse. It’s the expansion and contraction of air due to temperature changes, and it has nothing to do with foam
It must be related to temperature; it’s not necessarily connected to the foam.
The temperature is the same for all of them; all the parallel samples are at the same temperature, and the storage conditions are identical as well. I just don’t understand why they collapse