Hand Watch Glass

A watch glass is a small, circular laboratory tool resembling a shallow, convex glass dish, typically made from heat-resistant borosilicate glass or clear soda-lime glass. Its name derives from its historical similarity in shape to the glass covering of a pocket watch.

Primarily used for holding small quantities of solids, liquids, or samples, it serves multiple purposes in labs:

Evaporation: It can hold liquids over a heat source (e.g., a beaker of boiling water) to gently evaporate solvents, leaving behind solids or concentrated residues.

Covering: It often acts as a loose lid for beakers or flasks, preventing dust, contaminants, or splatters from entering while allowing vapor to escape.

Weighing: Its flat, clean surface makes it suitable for holding solid samples during weighing on a balance, especially powdery or small materials.