Scientists use test tubes for many purposes, including chemical reactions, distillations and storing chemicals and biological samples. Biologists use test tubes to grow seeds and cultures for plant propagation. Students use them in experiments for observing the growth stages of plants and insects. In the home, some people use test tubes to store spices, oils and craft-related products.
Test tubes are clear glass cylindrical tubes that are open at the top and rounded at the bottom. Scientists use glass test tubes more than any other type of equipment for experiments. They are ideal laboratory equipment because they are inexpensive and their structure is heat-resistant. Also, they have clear glass walls, which makes the contents visible during various stages of experiments, and the long structure of the tube helps prevent exposure to harmful substances and irritating fumes. Test tubes are also available in plastic, but they are not heat-resistant enough for experiments that require boiling of the tube's contents.
When using a test tube in a laboratory experiment, technicians hold them with tongs in the center firmly to keep them at a safe distance, and they never smell the contents or look directly into the opening of the tube. To avoid breakage or spillage, technicians store test tubes upright in a holder when they are not using them.