A laboratory test tubes is a slender, cylindrical piece of lab glassware, typically made of transparent glass or plastic. It has an open top for adding substances and a rounded or conical bottom, which helps prevent substances from settling and makes the tube easy to use with racks and holders. Laboratory test tubes are versatile and widely used for mixing, heating, and holding small amounts of liquids or chemicals during experiments. Glass test tubes can withstand high temperatures, making them suitable for direct flame exposure, while plastic test tubes are often disposable and preferred for biological samples to avoid cross-contamination.