Stopper (plug)

A stopper, bung, or cork is a cylindrical or conical closure used to seal a container, such as a bottle, tube, or barrel.

The water vapor would not be able to escape into the air, because the stopper and the tubing, if set up correctly, would be airtight.

[citation needed] In chemistry, bungs made of hardened rubber are frequently used in small-scale experimental set-ups involving non-corrosive gases.

[citation needed] For applications that place higher demands on the bung in terms of temperature and mechanical stability or solvent resistance, standardized glass stoppers and connectors are preferred.

[citation needed] Bottle stoppers made from gutta-percha, a natural rubber that is both chemically resistant and thermoplastic, were the first product of the Gutta Percha Company, better known for making submarine telegraph cables.