Lab flasks are containers to store or mix samples and solutions in a chemistry lab or other scientific setting. While they come in a wide variety of shapes suited to specific scientific applications, flasks generally have a wide body and one or more narrow necks. Some flasks may be sterile or autoclavable for reuse, and they come in a variety of capacities suited to their particular application, from 1mL volumetric flasks, to 250mL boiling flasks, to 15L spinner flasks. Flasks may be made of glass, borosilicate glass for heat resistance, or different types of plastic such as LDPE (low-density polyethylene), HDPE (high-density polyethylene), polyethylene, or polypropylene to provide resistance to particular chemicals or moisture. A flask may come with a stopper, a cap, or a ground glass joint to help contain material.
Flasks such as boiling flasks, retorts, reaction flasks, Kjeldahl flasks, Florence flasks, and Schlenk flasks, have a spherical body and one or more necks, and are used in scientific processes such as boiling and distillation. These flasks are typically made of borosilicate glass to withstand the temperature changes or thick glass to withstand pressure differences. Other flasks, like Erlenmeyer flasks , have a conical body and narrow neck for storing or mixing substances. A Büchner flask also has a secondary side neck for connecting to vacuum apparatus for filtration applications, and is made of thick glass to withstand pressure changes. Cell culture flasks are typically conical or rectangular in shape. Baffled bases in cell culture flasks help increase the surface area inside the flask and facilitate cell growth. Some cell culture flasks, called TC-treated flasks, may be treated with a tissue culture (TC) that increases oxygen on the interior surfaces of the flask to facilitate cell growth.
Volumetric flasks are designed to precisely measure the volume of a substance at specific temperatures, usually for preparing precise dilutions or standard solutions. They commonly have a round body with a flat base and long neck, and are made of glass or plastic. These flasks typically meet calibration and tolerance standards defined by organizations such as ASTM or ISO.