A test tube holder is used to hold test tubes. It is used for holding a test tube in place when the tube is hot or should not be touched. For example, a test tube holder can be used to hold a test tube while it is being heated. Moreover, when heating the tube with liquid or solid contained inside, the tube holder ought to tightly hold a test tube in order for the tube to be safely held while heating.
Particularly, for liquid heating, when holding a test tube holder with a test tube, hold it such that it aligns with the lab bench and also point the open end of the tube away from yourself or anyone nearby.