Calibrated glassware
Calibrated glassware is of two type: [1] that which is calibrated to contain a definite volume e.g., volumetric flasks and graduated cylinders; and [2]that which is calibrate to deliver prescribed volume, e.g., pipets and burets. The former should never be used as a substitute for the latter when accuracy is required because some liquid will always remain in the container, and the delivered amount will be less than the calibrated amount. On the other hand, pipets are calibrate to deliver definite amounts under specified conditions and must always retain a small amount of the liquid after delivery.