Stopper

Rubber (left and center upper row), cellulose (upper right row), amber and clear glass (left and center lower row), plastic (lower right row) stoppers

A stopper is a conical closure used to seal a container, such as a bottle, tube or other conical openings, like ground glass joints or spherical joints.

General

A stopper has the form of a cone frustum. It is made of glass, plastic (PE, PTFE), rubber, wood (cork), cellulose fiber. Glass and plastic stoppers have a flat head, for easy grabbing, as well as the classical "penny head" handle, though some glass models simply have a closed glass cylinder. The glass stoppers have ground glass joint more often than not. Some plastic and rubber stoppers have holes in them, through which tubes can be inserted to inject gas in the bottle.

Availability

Stoppers can be bought from lab suppliers. Rubber and cork stoppers can be found in many hardware stores.

DIY stopper

You can make a stopper by sculpting a rod of plastic. Rubber or cork can also be used.

See also

• Septum

References

Relevant Sciencemadness threads

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