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An Erlenmeyer flask, also known as a conical flask, is a widely used type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer, who created it in 1860.
The Erlenmeyer is usually marked on the side (graduated) to indicate the approximate volume of contents, and has a spot of ground glass or enamel where it can be labeled with a pencil. It differs from the beaker in its tapered body and narrow neck.
The opening usually has a slight rounded lip so that the Erlenmeyer can be easily stoppered using a piece of cotton wool, rubber bung or similar. Alternatively, the neck may be fitted with a female ground glass joint to accept a glass stopper. The conical shape allows the contents to be swirled or stirred during an experiment, either by hand or by a shaker; the narrow neck keeps the contents from spilling out. The small neck reduces evaporative losses compared to a beaker, while the flat bottom of the conical flask makes it unlikely to tip over and spill.
Erlenmeyers are used in chemistry labs for titration, e.g. for pH, as they can be held and the contents mixed single-handed leaving the other hand free to add reagent. Erlenmeyer flasks are extremely useful in the lab setting for stirring the contents by hand by swirling the flask, as the tapered neck prevents spillage of the contents.
Erlenmeyer flasks are suitable for heating liquids, e.g. with a Bunsen burner. The flask is usually placed on a ring held to a ring stand by means of a ring clamp. A wire gauze mesh or pad is usually placed between the rings and the flask to prevent the flames from directly touching the glass in the same manner as for a beaker. When heating (or cooling) in a water bath the flask can be clamped by the neck to a stand or a hooped weight may be placed over the conical part of the flask to prevent it from floating in the bath.[better source needed]
Erlenmeyers are also used in microbiology for the preparation of microbial cultures. Plastic Erlenmeyer flasks used in cell culture are pre-sterilized and feature closures and vented closures to enhance gas exchange during incubation and shaking.
- Flasks. IndiaMART. 17 November 2011
- Emil Erlenmeyer, "Zur chemischen und pharmazeutischen Technik," Zeitschrift fuer Chemie und Pharmacie, vol. 3 (January 1860), 21-22. He wrote that he first displayed the new flask at a pharmaceutical conference in Heidelberg in 1857, and that he had arranged for its commercial production and sale by local glassware manufacturers.
- Laboratory Glassware. 17 November 2011
- Erlenmeyer Flask. The Titi Tudorancea Learning Center. 17 November 2011
- Media related to Erlenmeyer flask at Wikimedia Commons