Uses
Ground glass stoppers and rubber stoppers are commonly used with laboratory glassware, mainly because of their nonreactivity. Some stoppers used in labs have holes in them to allow the insertion of glass or rubber tubing. This is often used when a reaction is taking place in the flask or test tube and the byproduct or result of the reaction is desired to be collected. For instance, if one were to boil water in a test tube and wanted to collect the water vapor, one could seal the test tube with a stopper with holes in it. With tubing inserted into the hole(s), when the tube is heated, water vapor will rise through the hole, make its way through the tubing, and into the collection chamber of choice. 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.
A phoedelia is a particular type of stopper, usually made of glass and decorated with a cross, used with ecclesiastical cruets.
Plastic bungs are commonly used to stop the air leaking from the lower parts of an air-bed. This type of bung is commonly made in two parts; the plastic outer screw on cap and the inner rubber bung used to seal the hole.
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