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Measuring Liquids |
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When you measure the volume of a liquid it is important to make sure that you use the appropriate instrument. Graduated cylinders, burettes, and measuring pipettes are marked with a measurement scale and are far more accurate than beakers. Graduated cylinders are used to find the volume of a liquid that you have, while burettes and pipettes are designed to measure the volume of a liquid that you are adding to a different vessel. Select an instrument of the appropriate size. For example, don't use a 250 ml graduated cylinder to measure 6 ml of water. A 10 ml graduated cylinder will give you more accurate results. When you put a sample of a liquid into one of these instruments you will notice a curve at the surface of the liquid. This curve, which is called a meniscus, may be concave (curved downward) or convex (curved upward). Hold the instrument so that the meniscus is at eye level. Read the volume of the liquid at the bottom of a concave meniscus or at the top of a convex meniscus. Please forward all questions, comments and criticisms to Gregory L. Curran.
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