Cold finger
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cold_finger".

Cold fingers.

Cold finger, a piece of laboratory equipment that is used to generate a localized cold surface, and is named for its resemblance to a finger.

Typically a cold finger is used in a sublimation apparatus, or can be used as compact version of a condenser in either reflux reaction or distillation apparatus.

The device usually consists of a chamber in which a liquid (typically cold tap water) can enter and leave. Another version involves filling the device with a cold solid such as ice, or dry ice.

Gallery

Dark green crystals of nickelocene, freshly sublimed on a cold finger.

Camphor being sublimed. Note the white purified camphor on the cold finger, and the dark-brown crude product.

A cold finger which includes a vacuum outlet.

Cold finger used in sublimation

Popular References:

ColdFinger: The arch enemy of SuperDude, a fictional character played by Kenan Thompson in the Nickelodeon show All That.