Meniscus

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For other uses, see: meniscus (anatomy) and lens (optics).

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 have a stronger attraction to each other than to the container.^[1] This may be seen between mercury and glass in barometers.^[2] Conversely, a concave meniscus occurs when the molecules of the liquid attract those of the container. This can be seen between water and glass. Capillary action 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 in plants.

When reading a scale on the side of a container filled with liquid, the meniscus must be taken into account in order to obtain a precise measurement. The measurement is taken with the meniscus at eye level to eliminate parallax error, and at the central point of the curve of the meniscus, i.e. the top of the meniscus, in the unusual case of a liquid like mercury, or more usually, the bottom of the meniscus in water and most other liquids.

[edit] References

[edit] See also

• Capillary action
• Contact angle
• Surface tension