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 frequently made of glass, though some are constructed from heat-resistant plastic or metal. They are used across various scientific disciplines, including chemistry and biology.
What Beakers Are Used For
Beakers serve a variety of practical purposes, primarily for holding, mixing, and heating liquids. Their wide mouths and straight sides make them suitable for these general applications. While beakers feature graduated markings, these lines provide only approximate volume indications.
These containers are ideal for tasks where precision is not the main concern, such as preparing solutions, performing chemical reactions, or transferring liquids. They are also commonly used as temporary vessels or for collecting filtrates during experiments. Their versatility makes them a staple in most laboratory environments.
Why Beakers Aren’t for Precise Measurement
Despite having volume markings, beakers are not suitable for accurate liquid measurements due to design limitations. The wide mouth and cylindrical shape contribute to less precise readings compared to narrower glassware. Liquids can also adhere to the beaker walls, which can cause the actual volume to differ from what is indicated.
The etched graduations are typically accurate only to within a 5% to 10% margin of error. This uncertainty means the markings are for rough estimations, not exact volumetric analysis. Relying on a beaker’s markings for highly specific volumes can lead to unreliable results.
Instruments for Accurate Liquid Measurement
When precise liquid volume measurement is necessary, other laboratory instruments are used. Graduated cylinders offer significant accuracy improvement over beakers, typically having an error range of 0.5% to 1%. These narrower, taller cylinders have finer, more closely spaced markings, making them suitable for measuring various liquid volumes reliably.
For higher precision, volumetric flasks prepare solutions of exact concentrations. These flasks are calibrated to hold a single, specific volume with a low margin of error, often less than 0.2%. Pipettes, especially volumetric pipettes, transfer small, highly precise liquid volumes. They offer exceptional accuracy, typically within 0.2% error, and are essential for sensitive analytical procedures. Burettes, with precise stopcocks, dispense liquids in titrations with high control and accuracy, often to 0.05 mL.