Erlenmeyer flask
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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.[1] It is named after the German chemist Emil Erlenmeyer, who created it in 1861. [2][3]
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[edit] Design
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. [4]
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.
[edit] Uses
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.[5]
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 ring 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.[6]
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.
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[edit] External links
Media related to Erlenmeyer flask at Wikimedia Commons
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