Watch glass

November 1, 2021

Among the glass elements of a laboratory, it is worth highlighting the watch glass, a fragile glass sheet of concave shape with many uses in a chemistry, biology and even physics laboratory. This element can be used as a simple beaker lid, up to a container for mildly corrosive products.

What is it?

It is a sheet of concave or convex shape, depending on which side you look at it, made of thin glass. It gets its name from the resemblance it shares with the crystal of the pocket watches of yesteryear.

It is made of metal or special glass, which can withstand up to 150º, you should never exceed those limits, especially if you are using it to evaporate liquids, otherwise it could fracture.


Among the most outstanding characteristics of a watch glass we have:

  • It is very stable, with a molded base to avoid accidents.
  • It can work from 120ºC to 150ºC.
  • It is available in the following sizes and weights:
Diameter (mm)607099118.5
Weight (g)3.75.51015

What are its uses?

It is used in a laboratory to evaporate liquids, to cover beakers, to weigh solid items on a balance, and to contain slightly corrosive substances. It is a medium-sized and very fragile item.

It is often used to prevent dust from entering a container, especially beakers . As the seal it provides is not hermetic, it allows gases to escape, preventing any dangerous reaction.

It is especially useful for weighing solids, although it can be used to weigh already filtered wet samples.

Keep in mind that this element must be handled with extreme care, as it is very delicate and fragile, any fall or blow can cause its fracture and with it, an obvious risk of accidents and contamination in the laboratory. Be cautious when using it.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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