Let’s take a look at the most common chemistry lab glassware. From chemistry to cell culture, there is one thing all science laboratories will always have infinite use for – glassware. Scientific glassware has been in use for centuries, starting with ancient Phoenicians, who used campfires to melt and fuse obsidian into useful tools. We’ve progressed considerably since then, but the usefulness of glass equipment is as constant as it ever was. Indeed, you would be hard-pressed to find an experiment in any kind of scientific lab that doesn’t involve at least one of the tools listed in this article!
There are some things most pieces of laboratory glassware have in common. All laboratory glassware, with very few exceptions, is made with borosilicate glass. Borosilicate glass is made primarily using silica and boron trioxide (an oxide of boron). This glass is extremely resistant to thermal stress. It also has excellent resistance against most chemicals (excluding sodium hydride, which can react with it). Both of these properties make it ideal for laboratory work. There are some alternatives, like fused quartz, which are also very resistant and sturdy, but the low cost of manufacture means that borosilicate glass wins out for common use.
In this article, we go over the most typical uses for common laboratory glassware. However, it’s worth noting that these are not the only uses! Scientists know how to take advantage of whatever they have on hand, so don’t be surprised if one day you walk into a lab and see someone using a watch glass as a lid, or a beaker as a mini trash receptacle. We make do!
Lab Glassware: Beakers
You’re bound to find at least a dozen of these in any lab you go to. Beakers are the most common type of laboratory glassware. They are primarily used for pouring, mixing, and measuring liquids. They’re typically found in volumes ranging from 10 mL to 1000 mL, although larger volumes are available. However, they’re not the most accurate. Most beakers are printed with an error percentage, which usually ranges from 5-10%. In other words, if you filled a 500 mL beaker up to the top mark, you might have anywhere from 450 to 550 mL in it. This is fine in situations where exact measurements aren’t important, but for more precise solutions one would typically use a different piece of equipment for the job.
Lab Glassware: Erlenmeyer Flasks
Erlenmeyer flasks, also known as conical flasks, are flat-bottomed flasks with a wide base and narrow neck. Their shape makes them ideal for swirling liquids to mix them without the risk of spilling. Because of this, they’re commonly used for titration experiments. They’re also used for boiling liquids- their shape results in less solvent loss as hot vapor will condense on the upper section of the flask. In microbiology, they’re used for growing cell cultures. Erlenmeyer flasks are available in a wide range of sizes, typically ranging from 250 to 2000 mL (although larger sizes can be found). Fun fact – Erlenmeyer flasks were designed by Emil Erlenmeyer, a German chemist active in the 19th century, who once worked in the lab of Robert Bunsen.
Erlenmeyer flasks can also have a sidearm to enable filtration. This flasks are known as filtering flasks, vacuum flasks, or Buchner flasks. A hose can be fitted to the sidearm, which is attached on the other end to a vacuum pump. A filter is placed on the top of the flask and a vacuum created, which pulls the filtrate down through the filter. Filtering flasks often have thicker walls than “standard” Erlenmeyer flasks.
Remember how we said you might use a different piece of equipment in the chemistry lab for more precise solutions? Odds are it’ll be this one. Graduated cylinders are, as the name suggests, tall glass cylinders with regular markings (graduations) on them that denote the exact quantity of liquid being measured. Graduated cylinders typically come in sizes ranging from 10 mL to 1000 mL. They are more accurate than beakers, but still do have some margin of error. Despite this, they’re the most commonly used glassware for measuring liquids.
Volumetric flasks are special flasks used for very precise measurement of liquids – no chemistry lab would be complete without them. These flasks are usually pear-shaped at the bottom with a tall, narrow neck. Each volumetric flask is designed to measure a specific volume. This is denoted by a single graduation on the neck of the flask. Volumetric flasks come in various sizes ranging from 1 mL to 20 L of liquid.
When many people think of chemistry lab glassware – they think of test tubes. A test tube is a small cylinder of glass (usually around 3-4 inches long) open at the top and closed at the bottom. Test tubes can be round bottomed, flat bottomed, or conical bottomed, but round bottomed test tubes are the most common. Test tubes are typically used to hold, mix, or heat small quantities of chemicals, especially for qualitative experiments and assays. Special test tubes known as culture tubes are also commonly used in microbiology labs to culture organisms such as bacteria, mold, seedlings, and plants cuttings.
Pipettes are long, narrow tubes tapered at one end. They are used to measure and dispense specific volumes of liquid. There are several types of pipettes, but we’ll focus on two of the most widely used ones: volumetric and graduated pipettes.
Volumetric pipettes, similar to volumetric flasks, are used to measure liquids to an extremely high degree of accuracy. These pipettes are long and narrow with a large bulb in the middle. Like volumetric flasks, each pipette is calibrated to a specific volume, and a single graduation denotes it. They are typically available in volumes of 1, 2, 5, 10, 20, 25, 50 and 100 mL.
Graduated pipettes have increments of volume marked all along the body of the pipette. They can measure a range of volumes, although each pipette has its own maximum volume. The range of volumes available is similar to those of volumetric pipettes. In general, the smaller the pipette, the more accurate it will be. This is why the standard rule is to always use the smallest volume of pipette that reasonably suits your needs. While graduated pipettes are available in glass, it is far more common for labs to use disposable plastic pipettes. These are less work to maintain, since you just throw them out, and come in sterile, individual packages, making them great for clean work.
Pipettes can be made of glass or plastic. Plastic pipettes are usually very inexpensive, and disposable. Glass pipettes are very clear and have greater clarity than plastic, but they can break and cause a dangerous mess. Plastic pipettes are safer, but it can be difficult to see the markings.
Round-bottom flasks are flasks with spherical bottoms. They are typically used for boiling or distillation. These flasks are particularly suited to this because of their shape, which allows for uniform distribution of heat. Typically, these flasks are used with a sand bath, in which a vessel of sand is placed on a heating mantle. This allows heat to gradually spread over the surface of the flask- it’s more even than just using a single heat source from below, and the temperature changes are less drastic, so there’s less risk of cracking the flask.
You have just learned the most common chemistry lab glassware. Of course, this is only a sampling of all the glassware scientists use. There are lots of other pieces of glassware that are more specialized than what’s in this article. Still, if you intend to do lab work in the future, it’s worth familiarizing yourself with everything we’ve discussed here since it’s almost certain you’ll encounter them!