Meniscus
Encyclopedia : M : ME : MEN : Meniscus
- This article is about the surface curvature formed by a liquid in a container.
For other uses of the term meniscus, see meniscus (anatomy) and lens (optics).
B: Read the top of a convex meniscus.
A meniscus (plural: menisci, from the Greek for "crescent") is a curve in the surface of a liquid and is produced in response to the surface of the container or another object. It can be either concave or convex. A convex meniscus occurs when the molecules of the liquid repel the molecules of the container or object. This may be seen between mercury and glass in barometers. Conversely, a concave meniscus occurs when the molecules of the liquid attract those of the container. This can be seen between water and glass. Surface tension acts on concave menisci to pull the liquid up, and on convex menisci to pull the liquid down. This phenomenon is important in transpirational pull.
The meniscus must be taken into account in order to obtain an accurate measurement of the level of liquid. As is obvious from the diagram at right in which a and b respectively contain the same volume of different liquids, if the meniscus is concave, the bottom is read on the container's scale. If the meniscus is convex, the top is read.
See also
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