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A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top, usually with a rounded U-shaped bottom. A large test tube specifically for boiling liquids is called a boiling tube. Test tubes are available in a multitude of lengths and widths, typically from 10 to 20 mm wide and 50 to 200 mm long.〔(MiniScience.com catalog: Test Tube ), accessed March 27, 2009〕 The top often features a flared lip to aid pouring out the contents; some sources consider that the presence of a lip is what distinguishes a test tube from a culture tube.〔Thomas Scott (transl., 1996), ''Concise Encyclopedia: Biology''. Walter de Gruyter. ISBN 3-11-010661-2, ISBN 978-3-11-010661-9. 1287 pages.〕 A test tube has either a flat bottom, a round bottom, or a conical bottom. Some test tubes are made to accept a ground glass stopper or a screw cap. They are often provided with a small ground glass or white glaze area near the top for labelling with a pencil. ==Uses== Test tubes are widely used by chemists to hold, mix, or heat small quantities of solid or liquid chemicals, especially for qualitative experiments and assays. Their round bottom and straight sides minimize mass loss when pouring, make them easier to clean, and allow convenient monitoring of the contents. The long, narrow neck slows down the spreading of vapours and gases to the environment. A test tube filled with water and upturned into a water-filled beaker is often used to capture gases, e.g. in electrolysis demonstrations. Culture tubes are often used in biology for handling and culturing all kinds of live organisms, such as molds, bacteria, seedlings, plant cuttings, etc.; and in medicine and forensics to store samples of blood or other fluids. A test tube with a stopper is often used for temporary storage of chemical or biological samples. Test tubes are usually held in special-purpose racks, clamps, or tongs. Some racks for culture tubes are designed to hold the tubes in a nearly horizontal position, so as to maximize the surface of the culture medium inside. Test tubes are sometimes put to casual uses outside of lab environments, e.g. as flower vases, glassware for certain weak shots, or containers for spices. Where large numbers of tests are run or only small amounts are available for testing, or both, microtiter plates are often used as small test tubes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Test tube」の詳細全文を読む スポンサード リンク
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