Which type of pipette is designed to measure a fixed volume of liquid?

The volumetric pipette is specifically designed to measure a precise, fixed volume of liquid. This type of pipette has a bulbous shape that allows for accurate measurement, and it is calibrated to hold a specific volume at a particular temperature. Its design minimizes the potential for error in liquid measurement, which is particularly important in laboratory settings where precision is crucial for experiments and analyses.

In contrast, a graduated pipette can measure variable volumes, as it is marked with a scale that allows the user to read different volumes, but it is not intended for measuring a single, fixed amount with the same level of precision as the volumetric pipette. The Pasteur pipette, on the other hand, is primarily used for transferring liquids rather than measuring exact volumes, and while disposable plastic transfer pipettes can measure liquids, they lack the accuracy and precision needed for tasks requiring specific volumes. Thus, the volumetric pipette stands out as the ideal choice for measuring a fixed liquid volume accurately.