In preparation for an upcoming effort I will need to mix up a solution. This solution needs to be of a particular concentration and to do that I’ll need to think back to chemistry class. One of the best parts of chemistry was mixing things together just to see what would happen, whatever the results. However, when one wishes to create something specific it’s important to know how to go about it.

It’s been my experience as an amateur microscopist that there are generally two types of guides out there; those made for children, and those made for professionals. I’m not saying there are no guides for the enthusiastic amateur, there are many very nice websites, periodicals, clubs, societies and forums out there which provide both advanced and accessible resources, I’m simply pointing out that if one picks up a book on the microscope or microscopic methods it’s apt to be either highly technical or exceedingly simplistic. Even the most technical of microscopy books can be wealths of information for the amateur, but such works often make certain assumptions concerning the knowledge of the reader in other fields, particularly chemistry.

Suppose one day in an effort to properly treat a specimen one follows a guide that calls for a 10% solution of something. At this point one has two options; purchase the solution, or purchase its components and prepare it ones self. If each of the components of the solution are liquids it’s a simple math problem. Computing the necessary ratio of components for any desired final volume is the work of a moment. However, when mixing a dry component and a liquid component things might get a bit tricky for people who have forgotten about mass.

To determine the ratio of two ingredients necessary when one is a solid and the other a liquid one must first measure them in a common unit, mass. When measuring each ingredient by grams it makes no difference if one or both is liquid or solid. To make things even simpler, one can look up the mass of a given volume of nearly any liquid and measure out the liquid component in milliliter and the solid component in grams.

The next time you see a recipe that calls for one part this and four parts that, just remember that the unit in which you measure is inconsequential so long as all ingredient are measured in the same unit, and consider buying a balance.