How to Make Connected Glass in Minecraft What Is the Use of a Watch Glass? Truk/flickr A sentinel glass is a piece of drinking glass that has a slight concave pattern. Frequently round with a diameter of 50mm to 150mm, the glass is most frequently used by chemists inside a laboratory setting. These scientists utilize the watch glass for a wide range of purposes including the evaporation of liquids to prevent contamination of beakers. Here is a closer expect at watch glasses and how they can be used within a science lab. Beaker Lid Scientists work on sensitive projects within the laboratory. Many of these activities deal with the monitoring and control of vapor saturation that takes place in the beakers they utilise. With watch glass, they tin can cover these beakers during their experim