Watch glass bowl
As a watch glass or watch glass in the are chemical laboratory technology curved windows of transparent material referred to in diameter from six to 20 centimeters.
The concave shape allows small amounts of liquids to be poured into watch glasses to allow them to evaporate . Watch glasses made of borosilicate glass can also be heated over Bunsen burners to accelerate evaporation.
Watch glasses are often used to briefly cover beakers , Petri dishes or the opening of flasks or bottles as protection against contamination, splashes and excessive evaporation. Today, in the laboratory, vessels are often covered with parafilm or aluminum foil as the sealing film instead of with watch glasses, and they are often completely sealed with sealing plugs .
Also suitable are watchglasses for one smaller amounts of substances and weigh or in oven to dry.
Individual evidence
- ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 1449.