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Liquid Volume Measuring Devices: The Graduated Cylinder and Buret
Like weighing, measuring liquid volume is a fundamental and frequently encountered lab
task
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As the name implies, a graduated cylinder is a cylindrical glass (or plastic) tube sealed
at one end with a calibrated scale etched (or marked) on the outside wall
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The measured volume corresponds to the volume of liquid contained
in the cylinder
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The volume of liquid in the graduated cylinder is obtained directly by reading the
calibrated scale
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The liquid surface is curved (U-shaped) rather than horizontal due to the relatively
strong attractive force between water and glass
...
) As a general rule, the bottom of the meniscus is taken as the liquid level in
the cylinder (and any other volume measuring device)
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For
example, the 50-mL graduated cylinder is divided into 1 mL increments
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1 mL increments, and the scale of a
500-mL graduated cylinder is divided into 5 mL increments
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The scale is
read to one digit beyond the smallest scale division by estimating (interpolating) between
these divisions
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1 mL
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01 mL and
the 500-mL graduated cylinder scale is read to the nearest milliliter (1 mL)
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A buret is designed to
dispense or transfer a precisely measured volume of liquid to another container
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The volume of liquid transferred is
obtained by difference (Vf - Vi) and it is sometimes designated as Vt
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The
scale of a 50-mL buret is divided into 0
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Therefore, when the liquid
level in a buret is read, it is read (and recorded) to the nearest 0
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Water or
aqueous solutions are the most common liquids used with a buret, and like the
graduated cylinder the bottom of the meniscus is taken as the liquid lever
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