Microscope Slides – The How and the Why
Any compound microscope needs to use slides to view anything. While you can purchase prepared slides, there is a certain satisfaction, or outright professional need to makes one’s own slides. Fortunately, blank slides are available for purchase. However there is a wide variety of slides available and some might get confused with what kinds of slides they need.
First of all is the basic slide: It is a 3″ x 1″ (75mm x 25mm) slip of glass about 1mm thick.
Basic slides can be made of plastic, but glass is much preferred. Not all slides are created equal and Spectrum sells Premium slides that have a much lower scratch-dig rating than standard slides.
Standard slides are also available with a frosted end. The glass is ground on one end of one side of the slide that makes it opaque. This is so that they can be labeled using a pencil without the need for stickers or other marks. Some slides have frosting on both ends for more information.
These two types of slides are all most folks will need for their flat slides requirements. The rest of the designs are needed in labs and industry.
Other slides go one step past the frosted end and have colored ends for labs where indexing the slides by type can be important.
These are important to labs where a lot of slides are produced and the lab needs to index the slides by type: white=bone samples, green=blood, etc. All the labels can be written on with pencil or felt-tip pen (sometimes ball-point).
There are also what are known as ‘charged’ slides. These are high-end microscope slides with a coating of a special adhesive formula (one side only!). This formula is very useful for getting specimens to ‘stick’ to the slide. These slides also have printed ends in varying colors.
For very large samples, there are even over-sized slides that are 3″ long by 2″ wide. These can also hold multiple samples for quick comparison:
These huge slides do have some issues: the are not as easy to handle, and they require a microscope with a large stage to fully take advantage of the size.
Now all of these slides are flat, which is fine for samples that need to be laid flat. This is fine for solid samples, or for liquids that are to be flattened underneath a cover slip. This is fine for observing dead materials, but what if you wish to observe living organism from say pond water or other sources? This is where concave slides come into play:
Concave slides are thicker than regular blank slides, and instead of a flat surface that have one or two small indentations that can hold liquids, such as the aforementioned pond water, blood or other liquids. This allows small creatures to be viewed without killing them. They may not be easy to find, but any water from a natural source should have some microscopic creatures in it.
Having a set of blank slides (and cover slips) at the ready is almost a requirement for owning a telescope. They are inexpensive and good to have when you find a new item to examine. Slide preparing kits can also help with stains and other materials to help prepare slides for viewing. Be sure to have some of these around if you plan to properly use your microscope.