Watch Glasses
Watch Glasses
Watch glasses are shallow, circular, and concave, and may be used as beaker or flask covers, weighing, crystallization, and drying. Watch glasses are available in a variety of sizes and materials compatible with virtually all industrial chemicals and solvents. Some models are non-stick and some can withstand temperatures from cryogenic ranges up to 260°C.
Types of Watch Glasses
Watch glasses are normally made from glass (borosilicate glass or soda lime glass) or from plastics such as autoclavable polypropylene or chemical-resistant PTFE. The plastic versions are often single-use and disposable to prevent sample cross-contamination.
• Glass versions may be constructed using shatter-resistant compositions
• Glass versions often have polished, fused, or ground edges for cut-free, safe handling and durability
• Plastic versions may be used at low temperatures and are also lighter in weight
• All versions are available in a range of diameters, thicknesses, and capacities depending upon the intended application
What are Watch Glasses Used for?
• Holding biological samples or specimens for examination, either with the naked eye or under the microscope
• Demonstrations and displays, particularly in educational or classroom settings
• Observation of chemical processes such as precipitation or crystallization
• Weighing of powders, crystals, or liquids
• Gentle heating and/or evaporation of solids and liquids (borosilicate versions)
• Temporary covers for beakers, cylinders, and other containers to reduce evaporation and minimize ingress of dust and other airborne contamination (the curved surface helps prevent sliding and helps return of condensed liquid to the beaker)
Eisco™ Watch Glasses
Range of different diameters.
Corning™ PYREX™ Watch Glass/Beaker Cover with Fire-Polished Edges
Molded for table stacking
Fisherbrand™ PTFE Watch Glasses
Inert to all materials except molten alkali metals.
Corning™ PYREX™ Ribbed Watch Glass/Beaker Cover
Ribbed design permits reflux of digestate and escape of excess vapor, thus preventing vapor buildup.
United Scientific™ Watch Glasses
Watch Glasses for covering boiling solutions.
Saint-Gobain Chemware™ PTFE Watch Glasses
Used for weighing, crystallization, and drying
GSC Go Science Crazy Cover Plates
Used to cover beaker and flasks. GSC International Cover Plates are made of glass.
Dynalon™ Polypropylene Watch Glasses
Allow closer observation of precipitates.