Laboratory instruments are renowned for their precision in size and composition. Measuring devices must be accurate to the smallest degree while containers must hold their contents securely without adding to or changing any of their characteristics. That’s why lab glassware is so dependable.
While some containers that were once made of lab glassware are now being made in plastic, the qualities of glass make its replacement by any other material impossible. Glass is inert, that is, it has the quality of being chemically inactive. It will not react with any chemical that it holds. It can be transparent allowing scientists to observe any chemical reactions taking place inside of a glass container. It is heat-resistant, as well. The image of a scientist in a lab coat holding a beaker or flask over a Bunsen burner is almost a stereotype in American culture. It is the heat-resistant quality of those items of lab glassware that make this image so universal.
Glass containers can also be opaque to protect the ingredients from the effects of light. Usually the non-transparent lab glassware is brown. Besides holding and storing chemicals and chemical mixtures, lab glassware may be used for measuring, heating, cooling, mixing, or prepping solutions, growing biological specimens – as in a Petrie dish – and containing a vacuum.
While plastics can be heat-resistant, transparent and inert, it is difficult to find pieces that rival lab glassware for all three qualities. In addition, because plastics are molded in a factory process, it is easier to fashion custom glassware when needed. Most of the large laboratories have glass blowers on staff to create custom lab glassware when the need arises. These glass blowers, trained in precision craftsmanship, have the responsibility for repairing lab glassware that would be difficult to replace and fusing together glass parts to form special pieces such as vacuum manifolds or reactions flasks.
Glass is also easy to clean and prepare for re-use. To make sure that all organic compounds, hydrocarbon or silicone grease, lab glassware is usually soaked in ethanol saturated with sodium hydroxide for an entire day. It is then rinsed with tap water. Any excess sodium hydroxide is removed by soaking the lab glassware in diluted hydrochloric acid for several hours before rinsing repeatedly and drying in an oven.
The qualities that make glassware useful at home are the same qualities that make glassware so useful. Although we take it for granted, it is difficult to say how much of our technology owes its existence to the precision of lab glassware.