Test Tube, What is it and how to choose the best one?

November 2, 2021

The test tube is a laboratory instrument used to mix or heat chemicals. They are open at the top and rounded at the bottom, and are generally made of glass or plastic materials. Some are designed to be reused, while others are disposable. One type of labware, test tubes are sometimes called culture or sample tubes, depending on the application. However, note that the culture tubes do not have a lip.

Chemists use test tubes to mix, heat, and hold small amounts of chemicals for laboratory tests and experiments. Biologists use them to grow and handle various organisms, fluids, and samples. Some test tubes, such as those used in clotting screens, contain prepared contents.

In hospitals, laboratories, and other medical facilities, blood collection tubes have colored caps or plugs to draw specific types and screens. There are several types of test tube materials: glass, plastic, metal, and ceramic. Glass and plastic are the most common, while metal and ceramic are less common. There are several subtypes of glass and plastic test tubes.

To ensure safety, sometimes gowns, other gloves are used. Other times, gas masks. There are also face shields, gowns, and many other protective measures. Another way to protect yourself in science is by using appropriate laboratory equipment to handle hazardous material . One such piece of equipment is called a test tube.

Next, we will talk in detail about the test tube, a material that can not be missing in any laboratory, just like the porcelain triangle . Join us!

What is a Test Tube?

A test tube, also known as a culture tube or sample tube , is a common piece of laboratory glassware consisting of a length of finger-shaped clear glass or plastic tube, open at the top and closed at the top. bottom. Test tubes are usually placed in special racks.

Test Tube History

Of all the basic shapes and sizes of average chemistry lab equipment , the test tube appears to be a relatively new addition – not mentioned, or anything like it, before the 19th century. One version says that the test tube came from the imagination of the Swede Jöns Jacob Berzelius. Considered one of the fathers of modern chemistry, Berzelius has more than enough accomplishments to his name, discovering silicon, selenium, and thorium, devising the chemical notation system, and establishing the differences between organic and inorganic compounds.

In light of that, conceiving the test tube might have been something he threw down in a moment of downtime on a rainy afternoon. Based on the evidence, he described something very similar to what we know as the test tube in an article he wrote in 1814, although this is more likely the genesis of the beaker named after Berzelius to this day. Another version holds that the test tube was the brainchild of Michael Faraday.

He is, of course, famous for his pioneering work in chemistry and electromagnetism, and for inventing an early version of what would become the Bunsen burner, plus the Faraday cage , which blocks electromagnetic fields. He first mentions the idea of ​​the test tube in his 1827 book Chemical Manipulation, suggesting that small glass tubes would be useful for testing reactions.

They would be a specially designed replacement for the wine glasses that Faraday and other chemists would normally reach for when they needed to store or mix small amounts of liquids.

Test tube description

A test tube is a clear glass or plastic container that is much longer than it is wide, commonly having a U-shaped bottom and an open top. It is essentially a cylinder-like equipment with one open end. There are many reasons why test tubes are made of glass or special types of plastic. This is because they possess some advantageous features, such as being leak-proof (as long as the tube doesn’t break, of course).

Compare that to a tube made of wire mesh . That wouldn’t be very leak proof, right? Glass and special plastic test tubes are also not reactive. Many metals react with all kinds of chemicals in ways that are dangerous or that would ruin an experiment or sample. The test tubes are also transparent. It’s hard to see what you’re doing with an experiment if the tube is made of wood, metal, or stone.

Importance of the test tube

The test tube is arguably the most inconspicuous piece of equipment in the lab – its workday function and ubiquity make it more or less invisible. However, scratch below the surface and you won’t find much. It has little in the way of a dazzling origin story. In fact, the start of the test tube is as opaque and colorless as many of the solutions it contains.

The materials that go into the manufacturing test tubes are generally exceptional, mostly plastic or glass, although Pyrex deviates slightly, and there is otherwise little to differentiate one test tube from another. Aside from the size, which generally ranges from 10-20mm wide, 50-200mm in diameter, and 100-150mm long.

Uses of the test tube in chemistry

Test tubes intended for general chemical work are generally made of glass, for better resistance to heat and corrosive chemicals and a longer service life. These tubes are made of glass resistant to expansion, mostly borosilicate glass can withstand high temperatures, up to several hundred degrees centigrade. Chemistry tubes are available in multiple lengths and widths, typically 10-20mm wide and 50-200mm long.

The top often features a flared lip to help pour the contents. A chemistry test tube generally has a flat bottom, a round bottom, or a conical bottom. Some test tubes are made to accept a ground glass stopper or screw cap. They are often provided with a small frosted glass or white enamel area near the top for labeling with a pencil.

Use of the test tube in biosciences

Culture tubes are test tubes used in biology and related sciences to manipulate and grow all kinds of living organisms, such as molds, bacteria, seedlings, plant cuttings, among others. Some culture tube racks are designed to hold the tubes in a nearly horizontal position.

Position, to maximize the surface of the growing medium indoors. The culture tubes for biology are generally made of transparent plastic such as polystyrene or polypropylene by injection molding. And they are often discarded after use. Plastic screw cap test tubes are often referred to as ‘Falcon tubes’ after a line manufactured by Becton Dickinson.

Use of the test tube in medicine

In clinical medicine, sterile air-drawn test tubes, called vacutainers , are used to collect and retain samples of physiological fluids such as blood, urine, pus, and synovial fluid. These tubes are commonly sealed with a rubber stopper, and they often have a specific additive placed in the tube with the color of the stopper indicating the additive.

For example, a blue top tube is a 5 ml test tube containing sodium citrate as an anticoagulant, used to collect blood for clotting and the glucose-6-phosphate dehydrogenase test. Small vials used in medicine may have a top cap, also called a hinge cap, molded into the vial.

Test tube resistance

Borosilicate glass is made with boric oxide, silica sand, and sodium carbonate. It has the vital property of a low coefficient of thermal expansion, in other words, it can withstand very high temperatures without stressing its shape, area or volume. This meant that the test tubes could be applied directly to a heat source, such as a Bunsen burner , which would raise the temperature of the liquid or solid inside, but leave the tube intact and unchanged.

While the actual heat resistance will vary depending on the properties of the specific type of borosilicate glass. It can typically withstand temperatures of up to several hundred degrees Celsius. It is also resistant to chemicals and has excellent optical clarity. So it quickly became the ideal material for the test tube and other glassware.

Boiling tubes

Boiling tubes are essentially scale test tubes . They are wider than normal test tubes to allow substances to boil violently. Other test tubes have caps or screw caps and these are the types that are used for temporary storage of biological samples. Or chemicals. Test tubes are also used for casual uses outside of laboratory settings. Where they can function as containers to hold a variety of items.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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