Continued from Part 2
Having covered flasks and other basics, there are a few more common types of lab glassware to discuss.
Test Tubes: Test tubes come in a variety of sizes, but overall that have the
same shape: A long tube with a rounded bottom. Test tubes are not meant to stand on their own, but to he held in the hand or stored is test tube racks. Test tubes are low cost and low volume, making them convenient for storage, side-by-side reactions, small quantity heating over a flame, and hundreds of other uses. They are probably one of the most common types of labware. Most test tubes are made of borosilicate glass so they can be heated, but sometimes test tubes are made of plastic.
Petri Dishes: Petri dishes are more used in biology than chemistry, but they have a place in the chemistry lab as well. The most frequent use of petri dishes is for growing bacteria cultures in an agar (nutrient) mix. Petri dishes are often considered disposable, so they most often made of plastic. However they can also be made of glass for situations where heat may need to be applied. Petri dishes typically have a simple bottom-and-top arrangement, and some designs may have grid patterns for measuring density and growth and others may be bisected into sections for comparison or simple space efficiency.
Reagent Bottles and Media Bottles: These bottles are used to store liquid
or powder chemicals. They are not made for reactions. They can be made of glass or sometimes plastic. Almost as important to the material the cap or lid. Some designs may use a glass stopper, others may have a screw-on cap depending on the reagent/media being held.
Distilling & Condensing Systems There are a huge number of distillation systems and apparati. They often have different purposes but the most basicone is to make distilled water by boiling it (and leaving the impurities behind) and then have a section where the evaporated water condenses again – either by having a jacketed sleeve, or condensing tube where cold water is pumped in fresh to cool & condense the steam back into water. There are many variations on this and going into them is beyond the scope of this article. Some systems are designed to distill other liquids, or separate them by heating. As one may expect, distilling and condensing systems are made of glass as plastic can rarely stand the heat involved.