Test tube

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Two small test tubes in a test tube rack.

A test tube, also known as a culture tube, is a piece of laboratory glassware composed of a finger-like length of glass tubing, open at the top, with a rounded U-shaped bottom. Often, the top features a flared lip.

Construction and Uses

Test tubes are available in a multitude of lengths and widths to serve a varying number of needs. They are typically used by chemists to retain multiple discrete samples of materials, usually liquids, during chemical procedures and experiments, and are designed to allow easy heating of these samples. Often, test tubes are constructed of expansion-resistant glasses such as Pyrex, and can usually be held in a flame such as that produced by a bunsen burner. A boiling tube is, however, preferred when heating samples for any length of time. It is used to hold chemicals.

Cultural Symbolism

Test tubes were once so ubiquitously used in biological and chemical procedures that, along with Erlenmeyer flasks and beakers, they are generally regarded as symbolic of science and scientific experimentation as a whole.

The term test-tube baby, referring to a baby born with the help of in vitro fertilisation, is a misnomer since neither glass nor test tubes are used in the procedure. "in vitro" is Latin for "in glass", referring to the test tubes.

See also

• One variation of the test tube is the vacutainer, used for the collection and storage of blood
• A boiling tube is a wider variation of the test tube, and is better designed for extensive and/or prolonged heating

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