What is the primary function of a test tube?

The primary function of a test tube is to hold small amounts of liquid for experiments. Test tubes are commonly used in laboratories for a variety of purposes, including mixing, heating, or storing samples of liquids. Their design allows for easy handling and observation of chemical reactions or biological processes on a small scale. They are typically made of glass or plastic and can withstand heat, which makes them versatile for various experimental needs. While other laboratory equipment exists for measuring volumes, storing larger quantities, or specific tasks like measuring temperatures, the test tube is specifically intended for small volumes in experimental contexts.