Pipettes are calibrated to be certain precision. Standard calibration is crucial to maintain their precision. Whenever you report the position on the meniscus, make sure to have your eye parallel to it in order to avoid parallax errors. Pipettes can range between disposable plastic pipettes to increased-grade, extra complex pipettes; https://beaucgfge.blogspothub.com/28897892/an-unbiased-view-of-different-types-of-pipette