 Beakers of several sizes |
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| Uses | Liquid volume containment and measurement |
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| Related items | Fleaker |
A beaker is a simple container for stirring, mixing and heating liquids commonly used in many laboratories. Beakers are generally cylindrical in shape, with a flat bottom and a lip for pouring.[1] Many also have a small spout to aid pouring as shown in the picture. Beakers are available in a wide range of sizes, from one millilitre up to several litres.
Standard or "Low-form" beakers typically have a height about 1.4 times the diameter.[2] The common low form with a spout has been called the Griffin form.[3] "Tall form" beakers have a height about twice the diameter.[2] These are sometimes called Berzelius beakers.[4]
A beaker is distinguished from a flask by having sides which are straight rather than sloping. The exception to this definition is a slightly conical sided beaker is called a Phillips beaker.[5]
Beakers are commonly made of glass (today usually borosilicate glass[2]), but can also be in metal (such as stainless steel or aluminium) or certain plastics, (notably polythene, polypropylene, PTFE). A common use for polypropylene beakers is gamma spectral analysis of liquid and solid samples.[6]
Beakers are often graduated, that is, marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume. These marks are not intended for obtaining a precise measurement of volume (a graduated cylinder would be a more appropriate instrument for such a task), but rather an estimation.
The presence of a lip means that the beaker cannot have a lid. However, when in use, beakers may be covered by a watch glass to prevent contamination or loss of the contents, but allowing venting via the spout.
References
- ^ Oxford English Dictionary 1989 edition
- ^ a b c British Standard 6523 (1984) Glass beakers for laboratory use
- ^ A. I. Vogel (1974) Practical Organic Chemistry Third edition (Longman, London) page 46 ISBN 0 582 44245 1
- ^ www.sigmaaldrich.com Manufacturer's catalogue
- ^ www.lennox.ie Manufacturer's catalogue
- ^ www.drct.com Manufacturer's catalogue
Further reading
- ASTM E960 - 93 (2008) Standard Specification for Laboratory Glass Beakers
See also
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