Describe How the Meniscus Is Used to Read Volume Measurements on a Graduated Cylinder.
Liquids are difficult to measure with the naked eye due to surface tensions causing a meniscus to form on the circumference of the measuring object. In this commodity, you will larn what a meniscus is, why it forms and how you can accurately and precisely measure the volume of a liquid in laboratory graduated measuring glassware or plasticware.
What is Meniscus?
The meniscus of a liquid is the upwards or downwards curve seen at the meridian of a liquid in a container. The nature of curve whether upward (convex) or downwardly (concave) depends on the surface tension the liquid and its adhesion chapters to the wall of the container.
Concave Meniscus (Run across diagram A)
A concave meniscus occurs when the molecules of liquid are strongly attracted to the container wall rather than to each other. In that case, liquid appears to 'stick' from the edges forming a concave shape.
Convex Meniscus (See diagram B)
A convex meniscus appears when molecules of liquid are strongly attracted to each other rather than to the wall of container. Near liquids, including water, testify a concave meniscus but a great case of a convex meniscus is liquid mercury in a glass container. It is to be noted that in some cases, the meniscus appears in a straight line instead of whatsoever curvature at all. For example, water in some plastic cylinders. No meniscus makes measuring very easy.
How to read a meniscus correctly
You must get at centre-level with the meniscus to obtain an accurate reading. Option up the glassware to bring it up to eye level or bend down to take a measurement.
The key to getting an authentic reading, is to measure the eye of the meniscus whether it be concave or convex. East.k. with a concave meniscus, measure the lesser of the meniscus and for convex meniscus, have the reading from the top of the meniscus. (See diagram reading line in the diagram A and B).
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Source: https://www.westlab.com/blog/2017/11/21/how-to-read-a-meniscus-in-chemistry
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