What are the types of glass test tubes

A glass test tube is a common and simple glass instrument used to hold a small amount of medicines for experiments in chemistry, physics, biology, medicine, agriculture, and industry. According to the different raw materials, glass test tubes can be divided into two types. One is an ordinary glass test tube, which is made of ordinary instrument glass. This kind of glass is easier to burn and fry, so it is only used for the test without heating, or for the test of heating the solution with a low boiling point. Its price is relatively cheap.
The other is the extra-hard glass test tube, which is made of extra-hard glass. Compared with ordinary instrument glass, this kind of glass is lower, and it is not easy to burn and fry, so it can be used for heating a small amount of solid. When doing scientific research on some precious materials such as rare metals, radioactive substances, spices, etc., or when testing concentrated acids, concentrated alkalis, and dangerous drugs, it is safer to use extra-hard glass test tubes. This kind of glass test tube is more expensive than ordinary glass test tube.
According to the difference of use, glass test tubes can also be divided into three categories, namely general glass test tubes (flat or inverted), graduated glass test tubes and branched glass test tubes. The flat glass test tube is suitable for general chemical reactions, the inverted glass test tube is suitable for adding a rubber stopper, the graduated glass test tube can replace the measuring cylinder, and the branched glass test tube can be used for a small amount of distillation.