Method of use of watch glass

Wash and dry the watch glass before use. The watch glass has a wide range of uses, but no matter what kind of instrument it replaces, it should be used in accordance with the method of use of various instruments. For example, when making gas chamber identification, two watch glasses are attached to one of the above watch glasses with a plane syngas chamber made of grinding and a test paper soaked with reagents. The identified compounds are placed on the following watch glasses, and the temperature is heated when necessary to observe the gas generated in the reaction, and the gas is identified from the color change of reagents. If white precipitation or turbidity is observed, a piece of black paper can be put on the bottom wall of the watch glass, and the white product can be clearly visible. If you do all kinds of instrument covers, as long as you use its arc on the mouth of the instrument, put it firmly, but pay attention to the choice of watch glass according to the caliber of the instrument. Generally, the diameter of the watch glass should be greater than the diameter of the instrument 1cm, so that it is more convenient to use. For beaker LIDS, choose watch glasses of different diameters according to beaker capacity.