FLAT BOTTOM FLASK: WHAT IT IS AND WHAT IT IS FOR - CHEMISTRY - 2025

The flat bottom flask is a flat bottom glass flask that is commonly used in laboratories and other scientific settings. Flasks come in many shapes and sizes, but they all share one thing in common: they have wide bodies at the bottom and a narrower section at the top, called the neck. They are traditionally made of glass, although some may be plastic.

Laboratory flasks are differentiated by the amount of volume they can hold, typically this is specified in metric units such as millimeters or liters.

An example of a flat bottom flask

These can be used to make solutions or to contain or collect them. Sometimes they can also be used to volumetrically measure chemicals, samples, solutions, etc. They are also used to carry out chemical reactions, or in other processes such as mixing, heating, cooling, dissolving, precipitating, boiling, distilling or analyzing.

Characteristics of flat bottom flasks

Flat bottom flasks are round flasks, usually composed of a single neck, that are used to heat compounds in distillation or other reactive reactions.

They are usually used to contain liquids and to heat them. The most common is that a kind of gauze material is used that is interposed between the flask and the flame. Additionally, flat-bottom flasks are widely used in the preparation of bacteriological culture media.

Unlike round bottom flasks, which cannot stand on their own, flat bottom flasks are able to do so because of their flat bottom.

These flasks are very good at heating substances; however, flat bottoms have the disadvantage of not heating as uniformly as their round bottom counterparts. The round flasks should be used with a laboratory system to support them and that they do not fall.

On the other hand, the flat bottom flasks can be stopped without any problem; no additional equipment is needed for them to be used. Almost all round flasks are made of borosilicate glass.

Flat bottom flasks are not as strong or durable as round bottom flasks. Despite this downside, they have one feature going for them: they don't have the sharp, vulnerable corners of an Erlenmeyer flask, for example.

The biggest advantage of these flasks is that thanks to their flat bottoms they can stand by themselves on a hot plate, on a table or on a shelf.

Variations of flat bottom flasks

Erlenmeyer flask

Erlenmeyer flasks. Source: Bongoman via Wikipedia.

The Erlenmeyer flask is also known as a conical flask. It is a type of bottle with a flat bottom, a cone-shaped body, and a cylinder-shaped neck. It was created in 1860 by the German chemist Emil Erlenmeyer.

Erlenmeyer flasks have broad bases, with sides that taper upward toward a short vertical neck. They can be graduated, and commonly ground glass or enamel markings are used where they can be labeled with a pencil. They are usually made of glass or plastic and are built in different volume ranges.

The mouth of an Erlenmeyer flask may have a kind of lip that can be stopped using a piece of cotton, cork or rubber.

Alternatively, the neck can be used with some other connector to be used with other devices or connections. These modifications can be specifically designed for uses in vacuum filtration processes, for example.

Thanks to its narrow sides and slim neck, this flask allows the contents to be mixed by shaking, without risk of spilling. For this reason, they are used in degrees.

The shape of Erlenmeyer flasks makes them useful for boiling liquids; the hot vapors condense in the upper section of the flask, reducing solvent loss. Their necks also help to attach filter funnels.

These jars are also ideal for recrystallization. The sample to be purified is heated until boiling and enough solvent is added so that it dissolves completely. The jar you receive will have a small amount of solvent on it and will heat to a boil.

This hot solution is then filtered into the receiving flask. The hot vapors from the boiling solvent keep the filter channel warm, preventing premature crystallization.

In microbiology, these flasks are used to prepare microbiological cultures. When used in this area, they are usually vented to promote gas exchange.

Volumetric flask

These flasks are laboratory pieces, calibrated to hold a precise amount of volume at a particular temperature. Volumetric flasks are used for precise dilutions and preparation of standard solutions.

They are usually pear-shaped, with a flat bottom, and constructed of glass or plastic. The mouth has a piece of plastic or lid, to accompany a glass stopper.

The necks of the volumetric flasks are long and thin, with a ring to mark their graduation. This mark indicates the volume of liquid it contains when filled to that point.

Beaker

These simple flasks are used in laboratories to mix, combine and heat liquids. The beakers have a flat bottom, with a cylindrical shape. Sometimes they have a kind of spout at the top to help pour liquids. They are available in different sizes.

References

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