Definition and Meaning of Laboratory Test Tubes
It is a transparent cylindrical glass tube, also known as a test tube, usually open at one end and rounded at the other, used as a container for small quantities of a substance in laboratory tests and experiments. It is essentially a cylinder-like piece of equipment with an open end. There are many reasons why test tubes are made of glass or special types of plastic.
This is because they have some advantageous characteristics, such as being leak-proof (provided the tube does not break, of course). Glass and special plastic test tubes are also non-reactive. Many metals react with all kinds of chemicals in ways that are dangerous or would ruin an experiment or sample. 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, isn’t it ?
Function of the Test Tube
- Laboratory chemists use the test tubes to heat, hold and mix small amounts of liquid or solid chemicals during experiments. They have a round bottom and are made of borosilicate glass to withstand temperature changes and resist chemical reaction. The test tubes have transparent glass to allow monitoring and observation during an experiment.
- The straight sides and round bottom are designed to reduce loss of mass when pouring and also to facilitate cleaning. A capped test tube is used for sample storage and other storage purposes. The test tubes are fragile; thus they can easily break when not handled carefully.
- The function of a test tube is to hold, mix or heat small quantities of liquid or solid chemicals for qualitative tests and experiments. Test tubes also serve as temporary storage for chemicals to be used in chemical experiments. Specimens are generally made of borosilicate glass so that they can resist reaction with chemicals and withstand temperature changes without breaking.
- Some specimens are made of plastic and, in most cases, are disposed of after use, unlike glass specimens. Test tubes come in various sizes and shapes. The standard laboratory specimen size is 18 x 150 mm. Specimens that come without a lip are called culture tubes. They are usually used in biology to grow living organisms such as bacteria, molds and seedlings. In medicine, culture tubes are used to store fluids and blood samples.
- Boiling tubes are essentially test tubes to scale. They are wider than the normal test tube to allow substances to boil violently. Other specimens have stoppers or screw caps and these are the types used for temporary storage of biological samples or chemicals. Test tubes are also used for casual use outside of laboratory environments where they can function as containers to hold a variety of items.
History and Origin of the Test Tube
People have used glassware to contain chemicals and other substances since the days of medieval alchemy, but in many cases these were the same types of containers that people would use at home.
Very few containers were made specifically for experimental purposes, and even then only for wealthy scientists like chemist Antoine Lavoisier (1743-94). The standard equipment of modern science only emerged with the emergence of the laboratory in the 19th century.
The test tube, consisting of a cylindrical tube with a rounded bottom and a lid with a lip, was developed in the early 19th century and the Petri dish a century later. Without a doubt, one of the most emblematic laboratory equipment ever created is the humble test tube, which has been a staple of laboratories around the world for generations. Here we take a quick look at the history and evolution of this iconic symbol of science.
Since medieval times, alchemists have been using glassware to store a variety of chemicals, however, these were not specifically designed for experimental purposes and it was not until the early 1800s that the test tube was developed. These early test tube designs consisted of a cylindrical tube with a lip top and a rounded bottom, the characteristic features of the test tube that we would recognize today.
During the 20th century, the test tube really took hold, and became a true symbol of science, and today the test tube is widely used by scientists for a variety of experimental purposes. For example, chemists often use devices such as test tubes to mix and heat chemicals. Test tubes also have a number of applications in other scientific disciplines, such as biology, and have helped to uncover a number of important scientific advances.
One of the most significant ideas associated with the test tube is the concept of so-called «test-tube babies,» a term used to refer to babies conceived through In Vitro Fertilization (IVF), which literally means fertilization in a cup. The first test-tube baby, Louise Brown, was born in 1978, and since then many people have benefited greatly from IVF treatment.
Dolly, the sheep, also began her life in a test tube, and was the first mammal clone created from an adult cell, causing great excitement in the scientific community and representing a breakthrough in the development of cloning technology. Two renowned chemists, Jons Jacob Berzelius (1779-1848) and Michael Faraday (1791-1867), have been suggested as the inventor of the test tube. Berzelius describes the test tube’s more robust cousin, the boiling tube, in an article from 1814.
Faraday mentions that small glass tubes would be a useful vessel for test reactions in his 1827 book, Chemical Manipulation. In any case, the test tube probably has its origin in the early 19th century, as the shape does not seem to appear in 18th century chemistry sets. Instead, the earlier texts suggest carrying out test reactions in wine glasses.
What is the Laboratory Test For ?
- The test tubes have many purposes, including chemical reactions, distillations and storage of chemical products and biological samples. Biologists use test tubes to grow seeds and crops for plant propagation. Students use them in experiments to observe the growth stages of plants and insects.
- In the home, some people use test tubes to store spices, oils, and crafts. Test tubes are clear glass cylinders that are open at the top and rounded at the bottom. Scientists use glass test tubes more than any other type of equipment for experiments.
- They are ideal laboratory equipment because they are economical and their structure is heat resistant. In addition, they have transparent glass walls, which makes the contents visible during various stages of the experiments, and the long structure of the tube helps prevent exposure to harmful substances and irritating fumes.
- The test tubes are also available in plastic, but they are not heat-resistant enough for experiments that require boiling the tube contents. When a test tube is used in a laboratory experiment, technicians hold them with clips in the center firmly to keep them at a safe distance, and never smell the contents or look directly into the opening of the tube. To avoid breakage or spillage, technicians store the specimen upright in a holder when not in use.
Use of the Laboratory Tests
- Chemistry: Chemists widely use the test tube in laboratories to treat chemical products, especially for experiments and qualitative tests (laboratory glass tube).
- Their spherical bottoms and vertical sides reduce the loss of mass during pouring, make them easier to wash and allow optimal control of the contents.
- The long and narrow neck slows down the propagation of gases to the environment.
- Medicine: in clinical medicine, they are used without air. They are called vacutainers and are used to collect and retain samples of physiological fluids such as blood, urine, pus and synovial fluid.
- These glass tubes are usually sealed with a rubber stopper and often have a specific additive placed in the tube, with the color of the stopper indicating the additive.
- For example, a blue cap tube is a 5 ml test tube containing sodium citrate as an anticoagulant, used to collect blood for coagulation tests and glucose-6-phosphate dehydrogenase.
- Small bottles used in medicine may have a top cap (also called a hinge) molded onto the flask.
- Biology: Culture tubes are used in biology and related sciences for the manipulation and cultivation of all types of living organisms, such as molds, bacteria, seedlings, plant cuttings, etc.
- Some culture tube racks are designed to hold the specimen in a horizontal position. position to maximize the area of the culture medium inside.
- Culture tubes for biology are usually made of clear plastic (such as polystyrene or polypropylene) by molding and injection, and are often disposed of after use. Some sources consider that the presence of a lip distinguishes a specimen from a culture tube.
Other uses: test tubes are sometimes used as vases, glassware for some weak planes, or spice containers.
- Thorough cleaning and rinsing of the glass tubes between each use is vital, otherwise distorted results will be obtained in future experiments. The first step is to rinse immediately after use.
- Then, effective washing requires only a brush and hot soapy water. More difficult stains can be removed with acetone.
- For cloudy glassware or tubes containing resistant organic material, chromic acid can be used while wearing protective clothing.
- Boiling the glassware in a weak solution of sodium carbonate removes grease residue.
Price in Euros and Dollars of the Probe
- LEORX Test tube 4pcs blue transparent plastic graduated measuring line laboratory cylinder
- Price: 10,79
- Cikuso 100ml Clear plastic Test tube
- Price: 2,43
- Paterson PTP304 – 600 ml graduated cylinder, Clear
- Price: 9,12
Types of Test Tubes
There are several types of specimen materials: glass, plastic, metal and ceramic. Glass and plastic are the most common, while metal and ceramic are less common.
- Glass Test Piece Glass test pieces are thick-walled and resistant to heat and/or chemicals. Sometimes they are easier to see than plastic tubes, but often they are more expensive.
- Fused silica is suitable for applications that require good long-term thermal stability.
- Borosilicate glass can resist thermal shock and chemical attack, making it a common specimen material for chemical applications.
- Quartz glass combines high resistance to thermal shock with high infrared (IR) radiation transmission. Chemically pure and chemically resistant, it also has excellent high temperature properties.
- KIMAX® (Kimble Chase) is made from borosolicate glass and is resistant to breakage and chemical attack. It is sometimes disposable and/or recyclable.
- Pyrex® (Corning) is another type of proprietary borosolicate glass. Like KIMAX, it has greater mechanical strength and heat resistance than some other types of commercial glasses.
- Zerdour® (Schott Glass) is a lithium aluminosilicate glass-ceramic with a very low coefficient of expansion.
Other types of laboratory glass material are also available.
- Plastic test tubes Suppliers also provide test tubes made of a variety of plastic materials. These products are lighter and generally less expensive than glass tubes.
- They can also resist light and ultraviolet (UV) pressure. EPDM tubes offer good resistance to sunlight, weathering and ozone. The suggested operating temperature for EPDM is -70°F to 275°F.
- Fluoroelastomer products have good resistance to heat, oil and chemicals; however, they often have low performance at low temperature.
- Neoprene tubes are useful over a wide temperature range and resist degradation from ultraviolet light.
- Nitrile has a suggested operating range of -30°F to 275°F, making it a good choice for some low temperature applications.
- Nylon and polyamide products have good pressure ratings, and PharMed® (Norton Company) specimen has high tensile strength. PE specimens have excellent chemical resistance, but poor temperature resistance.
- Polyethylene (PE) also has excellent chemical properties, but is semi-opaque.
- Plastic specimens also include products made of polypropylene (PP), polytetrafluoroethylene (PTFE), polyurethane (PU), and polyvinyl chloride (PVC).
- Specifications and features When selecting specimens, buyers should specify the desired volume and may select disposable and/or graduated products. Generally, 18 mm x 150 mm is the standard specimen size.
It is a thin, cylindrical container that is scaled, usually in milliliters: it is used in a laboratory to measure and pour exact quantities of a liquid
It is a small glass tube with a closed and rounded end, used in scientific experiments.
- Test tubes are extremely common thin-walled cylindrical tubes that can be used to contain chemical solutions.
- Scientists use test tubes as containers for liquid chemical solutions, mixing, heating or cooling, culture production, and other applications.
- Because test tubes have rounded bottoms, they cannot stand alone and require a test tube stand or other device to hold them upright.
Chemistry Test Tubes
- Thistle tubes are tubes designed to allow chemicals to add material through a semi-permeable membrane or a specially designed cap.
- They have long stems that end in a reservoir bulb with a flared edge.
- Thistle tubes are specifically designed to fit into complementary caps on Erlenmeyer and other flasks, so that new materials can be introduced into other compositions.
Other Laboratory Materials and Instruments in ALPHAPEDIA
Other Topics of Interest in ALPHAPEDIA
Image and Photo of the Test Tube