A beaker is a common piece of laboratory equipment, typically a cylindrical container with a flat bottom and a small pouring spout. These vessels are used in various scientific settings, including chemical, biological, and clinical laboratories. Beakers come in a wide range of sizes, from a few milliliters up to several liters, to accommodate diverse experimental needs.
Most beakers are constructed from borosilicate glass, which offers heat resistance and durability, allowing them to withstand rapid temperature changes and corrosive chemicals. Beakers can also be made from certain plastics, such as polypropylene, often used for less demanding applications or when shatter resistance is needed. The side of a beaker usually features graduation marks, providing an approximate indication of the liquid volume.
Common Applications
Beakers serve multiple functions in a laboratory setting, making them versatile tools. They are frequently used for holding and temporarily storing various liquids, solutions, or solid samples. This includes containing reagents, buffering solutions, or collecting products and byproducts during experiments.
The wide mouth and flat bottom design of beakers make them well-suited for mixing and stirring substances. A stirring rod or magnetic stirrer can be used to combine chemicals thoroughly without significant spillage. This characteristic also facilitates the dissolution of solids in liquids when preparing solutions.
Borosilicate glass beakers are commonly used for heating solutions over a Bunsen burner or on a hot plate. It is important to heat liquids slowly and stir frequently to ensure even heating and prevent boiling over. Beakers have a pouring spout for controlled liquid transfer, but their graduation marks are only for approximate volume measurements, typically with an error of 5% or greater.
Comparing Beakers to Other Lab Glassware
While versatile for general laboratory tasks, beakers have limitations, especially concerning measurement precision. Unlike beakers, volumetric flasks are designed for highly accurate volume measurements. These flasks have a narrow neck with a single calibration mark, indicating a very precise volume, making them suitable for preparing solutions of exact concentrations.
Erlenmeyer flasks, also known as conical flasks, differ from beakers in their conical body and narrow neck. This shape reduces the risk of spillage during swirling or vigorous mixing, and the narrow opening also minimizes evaporation and allows for stoppers to be used. Erlenmeyer flasks are often preferred for titrations or reactions that produce gases, whereas beakers are better for general holding and mixing.
Graduated cylinders offer a higher degree of accuracy for volume measurement compared to beakers, typically having an error of 0.5-1%. Their narrower shape and finer graduation marks allow for more precise readings than beakers. Beakers are used for their versatility in tasks like mixing, heating, and temporary storage, rather than for precise quantitative measurements.