Whether for education or as a hobby, chemistry is an interesting area of science involving many specialty tools. Flasks are very important tools in chemistry and come in many shapes, sizes and accuracies of measurement. Each flask has a specific purpose, so it is important to know about each of the basic flask types. Most chemistry flasks are made of special glass that survives well under heating and does not leech minerals or chemicals into the solution stored within.
Beakers are the standard vessel used in chemistry. They come in all sizes including 5 milliliter (ml) flasks and flasks of many liters (L). Much like a cup or a mug, they consist of a cylinder of glass with a flat bottom made to hold liquid. Beakers may or may not have a pour spout although they usually do. They also may or may not have markings on the side labeling the approximate volume they contain. They are not very precise in their measurement and are made to contain chemicals or reactions. In the event that a beaker needs to be heated, a hot plate is ideal, but a Bunsen burner and beaker holder will also work.
Erlenmeyer flasks are flat-bottomed flasks that are similar to beakers, except that the sides taper in as they go up and form a narrow vertical neck. They also typically have measurement markings and pour spouts. They are typically used when chemicals need to be heated because their tapered sides help keep some of the heat in that might otherwise be convected away by evaporating materials. They can be heated over a Bunsen burner or a hot plate.
Round Bottom Flasks
Round bottom flasks do not stand up on their own and must always be held by a clamp. They typically do not have markings (other than a mark approximating volume) or pour spouts. They can be heated by Bunsen burner, or by a special type of hot plate that is made to accommodate the round bottom.
Volumetric flasks are a very precisely made type of flask. They are made to measure out relatively accurate volumes of liquid. They typically have a bulbous bottom that may or may not be flat, and a very long, very narrow neck. A marking on the neck is there for measurement. When the meniscus of the liquid in the flask is level with this mark, a relatively precise volume has been measured. The flask will also be labeled with the error margin for the measurement.