Most of us have used a graduated cylinder at some point in our lives, usually in high school chemistry. The cylinder with all the hatch marks in it and a plastic bottom? That was the graduated cylinder, which is probably one of the simplest and most useful pieces of equipment you’re likely to find in a lab.
Where the graduated cylinder is different from most of the other glassware you’d find in a typical lab setting is accuracy. Graduated means that the cylinder has been imprinted with marks that delineate exactly how much of whatever you’re putting in them.
This is not strictly limited to graduated cylinders, as you’ll find the same sort of thing on other laboratory glassware, but graduated cylinders are specifically designed so that the measurements are highly accurate. They are not quite as accurate as volumetric pipettes or volumetric flasks.
It used to be that they were primarily made out of glass, but this has changed in recent years. Now graduated cylinders are typically made of polypropylene, which is relatively unaffected by chemicals, or polymethylpentene, which is very clear. Both of these are much lighter than glass and much more resistant to shattering.
Graduated cylinders usually have a rubber bottom that covers the bottom of the actual cylinder. This means that unlike test tubes or culture tubes, you can sit them down safely. Likewise, there is often a rubber ring around the top that is meant to prevent it from breaking if it’s knocked over by preventing direct contact with other objects.
Typically, the measurements start at 20ml and are marked in 2ml increments thereafter. The proper way to get an accurate measurement from a graduated cylinder is to raise the cylinder to eye level, measuring the meniscus, which is the bottom of the curvature of the surface of the liquid.
Not surprisingly, graduated cylinders come in a wide variety of sizes. Generally, the smallest are going to be the extremely small and fairly rare 5ml graduated cylinder, which is used for extremely small measurements. They can also be found as large as 1000ml, which is usually enough volume for most lab settings. You can find larger ones than that, but you can expect them to be a lot more expensive than cylinders in the more standard sizes.
The most common use of a graduated cylinder is to measure the volume of a liquid, which is just a matter of pouring the liquid in and measuring the increments. You can also measure the volume of solid objects by filling it with water, dropping the object in and measuring the displacement.
Graduated cylinders are used in a wide variety of fields, and not just in the typical science related ones. They can be extremely handy for some kind of food manufacturing, and they are useful for making precise test batches of wine or beer. Always just make sure to buy a graduated cylinder that is the right type of material and size for your purposes.