Graduated cylinder
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A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of
laboratory equipment A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physicia ...
used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represents the amount of liquid that has been measured.


Materials and structure

Large graduated cylinders are usually made of
polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and ...
for its excellent chemical resistance or
polymethylpentene Polymethylpentene (PMP), also known as poly(4-methyl-1-pentene), is a thermoplastic polyolefin. It is used for gas-permeable packaging, autoclavable medical and laboratory equipment, microwave components, and cookware. It is commonly called TPX, ...
for its transparency, making them lighter and less
fragile Fragile or The Fragile may refer to: Film and television * ''Fragile'' (film), a 2005 film by Jaume Balagueró * "Fragile" (''Smallville''), a television episode Literature * ''Fragile'' (manga), a 2016 Japanese series by Bin Kusamizu and Sab ...
than
glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
.
Polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and ...
(PP) is easy to repeatedly
autoclave An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilizat ...
; however, autoclaving in excess of about (depending on the chemical formulation: typical commercial grade
polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and ...
melts in excess of ), can warp or damage polypropylene graduated cylinders, affecting accuracy. A traditional graduated cylinder is usually narrow and tall so as to increase the accuracy and precision of volume measurement. It has a plastic or glass base (stand, foot, support) and a "spout" for easy pouring of the measured liquid. An additional version is wide and low. Mixing cylinders have
ground glass joint Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from interchangeable commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may ...
s instead of a spout, so they can be closed with a stopper or connected directly with other elements of a manifold. With this kind of cylinder, the metered liquid does not pour directly, but is often removed using a
Cannula A cannula (; Latin meaning 'little reed'; plural or ) is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces ...
. A graduated cylinder is meant to be read with the surface of the liquid at eye level, where the center of the
meniscus Meniscus may refer to: *Meniscus (anatomy), crescent-shaped fibrocartilaginous structure that partly divides a joint cavity *Meniscus (liquid) The meniscus (plural: ''menisci'', from the Greek for "crescent") is the curve in the upper surface ...
shows the measurement line. Typical capacities of graduated cylinders are from 10 mL to 1000 mL.


Common uses

Graduated cylinders are often used to measure the volume of a liquid. Graduated cylinders are generally more accurate and precise than
laboratory flasks Laboratory flasks are vessels or containers that fall into the category of laboratory equipment known as glassware. In laboratory and other scientific settings, they are usually referred to simply as flasks. Flasks come in a number of shapes and ...
and beakers, but they should not be used to perform
volumetric analysis Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the ''titrant'' ...
; volumetric glassware, such as a
volumetric flask A volumetric flask (measuring flask or graduated flask) is a piece of laboratory apparatus, a type of laboratory flask, calibrated to contain a precise volume at a certain temperature. Volumetric flasks are used for precise dilutions and prepar ...
or
volumetric pipette A volumetric pipette, bulb pipette, or belly pipette allows extremely accurate measurement (to four significant figures) of the volume of a solution. It is calibrated to deliver accurately a fixed volume of liquid. These pipettes have a large bu ...
, should be used, as it is even more accurate and precise. Graduated cylinders are sometimes used to measure the volume of a solid indirectly by measuring the displacement of a liquid.


Scales and accuracy

For accuracy the volume on graduated cylinders is depicted on scales with 3
significant digits Significant figures (also known as the significant digits, ''precision'' or ''resolution'') of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something. If a number expre ...
: 100mL cylinders have 1ml grading divisions while 10mL cylinders have 0.1 mL grading divisions. Two classes of accuracy exist for graduated cylinders. Class A has double the accuracy of class B. Cylinders can have single or double scales. Single scales allow to read the volume from top to bottom (filling volume) while double scale cylinders allow reading for filling and pouring (reverse scale). Graduated cylinders are calibrated either “to contain” (indicated liquid volume inside the cylinder) and marked as "TC" or “to deliver” (indicated liquid volume poured out, accounting for liquid traces left in the cylinder) and marked “TD”. Formerly the tolerances for “to deliver” and “to contain” cylinders are distinct; however now these are the same. Also, the international symbols “IN” and “EX” are more likely to be used instead of “TC” and “TD” respectively.


Measurement

To read the volume accurately, the observation must be at an eye level and read at the bottom of a meniscus of the liquid level. The main reason as to why the reading of the volume is done via
meniscus Meniscus may refer to: *Meniscus (anatomy), crescent-shaped fibrocartilaginous structure that partly divides a joint cavity *Meniscus (liquid) The meniscus (plural: ''menisci'', from the Greek for "crescent") is the curve in the upper surface ...
is due to the nature of the liquid in a closed surrounded space. By nature, liquid in the cylinder would be attracted to the wall around it through molecular forces. This forces the liquid surface to develop either a
convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytope ...
or
concave Concave or concavity may refer to: Science and technology * Concave lens * Concave mirror Mathematics * Concave function, the negative of a convex function * Concave polygon, a polygon which is not convex * Concave set * The concavity In ca ...
shape, depending on the type of the liquid in the cylinder. Reading the liquid at the bottom part of a
concave Concave or concavity may refer to: Science and technology * Concave lens * Concave mirror Mathematics * Concave function, the negative of a convex function * Concave polygon, a polygon which is not convex * Concave set * The concavity In ca ...
or the top part of the
convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytope ...
liquid is equivalent to reading the liquid at its
meniscus Meniscus may refer to: *Meniscus (anatomy), crescent-shaped fibrocartilaginous structure that partly divides a joint cavity *Meniscus (liquid) The meniscus (plural: ''menisci'', from the Greek for "crescent") is the curve in the upper surface ...
. From the picture, the level of the liquid will be read at the bottom of the
meniscus Meniscus may refer to: *Meniscus (anatomy), crescent-shaped fibrocartilaginous structure that partly divides a joint cavity *Meniscus (liquid) The meniscus (plural: ''menisci'', from the Greek for "crescent") is the curve in the upper surface ...
, which is the concave. The most accurate of the reading that could be done here is reduced down to 1 mL due to the given means of measurement on the cylinder. From this, the derived error would be one tenth of the least figure. For instance, if the reading is done and the value calculated is set to be 36.5 mL. The error, give or take 0.1 mL, must be included too. Therefore, the more precise value equates to 36.5 \pm 0.1; 36.4 or 36.6 mL. Therefore, there are 3
significant figures Significant figures (also known as the significant digits, ''precision'' or ''resolution'') of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something. If a number expre ...
can be read from the given graduated cylinder picture. Another example, if the reading is done and the value calculated is set to be 40.0 mL. The precise value would be 40.0 \pm 0.1; 40.1 or 39.9 mL.


Gallery

File:Graduated cylinders-diagrams.svg, Two graduated cylinders. A traditional graduated cylinder (A in the image), and mixing cylinders (B in the picture)


See also

*
Measuring cup A measuring cup is a kitchen utensil used primarily to measure the volume of liquid or bulk solid cooking ingredients such as flour and sugar, especially for volumes from about 50  mL (2  fl oz) upwards. Measuring cups are also use ...
, a similar device used for cooking


References

{{DEFAULTSORT:Graduated Cylinder Laboratory glassware Volumetric instruments