Test tubes are small, cylindrical containers made of glass or plastic, commonly used in laboratories for mixing, heating, or storing liquids. They have an open top and a rounded bottom, which makes them easy to handle and allows for even heating. Scientists and students often use test tubes in experiments to observe chemical reactions or to hold samples for analysis. In addition to their use in science, test tubes are also popular in educational settings, where they help students learn about chemistry and biology. They can be found in various sizes and are often used alongside other laboratory equipment, such as beakers and pipettes, to conduct experiments safely and effectively.