Test tubes are cylindrical, open-ended containers commonly used in laboratories for various scientific experiments and analyses. They come in different sizes and materials, including glass and plastic. Test tubes are versatile and serve numerous purposes, such as holding small amounts of liquid, heating substances over an open flame, mixing reagents, and conducting chemical reactions. Their clear design allows for easy observation and measurement of liquids and solids. Test tubes are an essential tool in scientific research, enabling scientists to perform a wide range of experiments accurately and safely.