Know Your Lab Glassware: A Guide to Glass Beakers, Test Tubes, And Flasks

Indispensable in biological and chemical laboratories, lab glassware is traditionally made of heat-resistant glass but is now produced in plastics and plastic coated glass. Plastic ware is less expensive, less prone to breakage, and serves many purposes in the lab. Plastic coated glass is used for chemicals that present a danger if the glassware breaks. The plastic coating will hold the chemical until it can be properly disposed of. Glass is still preferred for many uses due to its transparency, heat resistance, and chemical stability.

The most commonly used glass is clear, borosilicate glass, also known as Pyrex, that can withstand the stress of heating. Brown or amber colored glass is used to keep contents protected from the ultraviolet and infrared spectrum of light and is available for glassware containers.

No matter what material laboratory glassware is made from, the names of the various glassware types remain consistent and are based on shape, volume, and intended use.

Flasks

Laboratory flasks are characterized by their shape, with a larger base and narrow open neck. Flasks serve a variety of purposes from collecting liquids to heating mixtures. They vary in size and shape, some having two necks. They are also produced in both plastic and glass.

Erlenmeyer flasks, also known as conical flasks, are the most common type of lab flask. First used by the German chemist Emil Erlenmeyer, they are flat bottomed and shaped like a cone with a single neck.

A Buchner flask is basically an Erlenmeyer flask with a small tube extending horizontally out of the neck. The side arm is specially made to tightly fit a flexible hose. These flasks are made of thick glass to withstand pressure changes as they are frequently used to create vacuums.

Volumetric flasks are precision flasks intended for accurate measuring of liquids. Metric measurements are marked on the flask. The flask has a pear or slightly bulbous shape with a long thin neck.

Florence, or round-bottom flasks are generally spherical with one or more long necks. There are some flat-bottomed Florence flasks that can sit without being supported. These are produced of borosilicate glass as they are used for boiling over a Bunsen burner and must be heat resistant.

A retort is designed for distillation. It has a spherical base and a very long thin tapering neck that points downward. Liquid is heated in the base, and the condensation then runs down the neck to a different container.

Beakers

Glass beakers are multi-purpose lab containers used for mixing and heating liquids. They have a cylindrical shape with a lip spout designed for pouring. Beakers are flat-bottomed and come in a variety of sizes, from one milliliter to large 10-liter plastic beakers. Although commonly made of borosilicate glass, plastic and stainless steel beakers are also produced. A beaker differs from a flask in their straight-sided shape. Most beakers are graduated, marked with metric units for measuring. They are used for a wide variety of purposes from mixing to heating.

Low form beakers differ from tall form beakers in the ratio of height to diameter. Low-form has approximately a 1.4 ratio while tall form is closer to 2. Flat beakers have a larger diameter than height and are used to evaporate liquids.

Bottles

Designed to contain liquids for storage, bottles come in a wide variety of materials, sizes, and shapes. Some are made with a flaring mouth to accommodate a glass stopper. Others have screw-on plastic caps. Bottles come in clear glass or amber glass for light sensitive liquids. They may be jar-shaped with a wide mouth, jug-shaped with a small thumb loop for secure holding, or have a square base.

Funnels

Funnels are inverted cones with a long straight neck. They are used for spill-free pouring from one container to another. They generally do not need to be heat resistant.

Burettes

Glass burettes are very long graduated tube shaped pieces of glassware used for accurate measuring of liquids. They are filled from the top and empty out of the bottom. A stopcock is located near the bottom to control the flow of liquids through the burette. They are manufactured for extreme accuracy and can be used to check measurements on other laboratory glassware. Burettes generally come with supports to hold them in place while measuring and release of liquids occurs.

Test Tubes

Test tubes are round-bottomed, cylindrical glassware widely used in laboratories to hold or mix small amounts of material. They can be stoppered with cork or rubber, and special racks are made to hold a group of test tubes. Test tubes are frequently used to culture organisms in biology, and special racks hold these almost horizontally for maximum culture medium surface.

Test tubes serve a wide variety of purposes from temporary storage in the lab to flower vases outside the lab. They are used by biologists, medical professionals, botanists, forensic technicians, and casually to contain everything from kitchen spices to beads.

About the Author

NovaTech International provides more information on Glass Beakers and other lab equipment.

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This entry was posted on Monday, September 6th, 2010 at 8:37 am and is filed under Vintage Electronics. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.