What is a test tube used for?

A test tube is a common piece of laboratory glassware used for holding, mixing, and heating small quantities of liquids. Test tubes are typically cylindrical, with a closed bottom and an open top. They are usually made of borosilicate glass, which is resistant to heat and chemicals.

Test tubes come in various sizes, ranging from a few milliliters to several tens of milliliters in capacity. They are often used in experiments to observe chemical reactions, conduct titrations, or culture microorganisms. Test tubes can also be used for storage purposes, as they are often sealed with a rubber stopper or screw cap.

Some test tubes have markings on the side to indicate volume measurements, making them useful for precise measurements. Test tubes are also commonly used in conjunction with a test tube rack, which holds multiple test tubes in an upright position for easy access and organization.