Friday, July 25, 2008

A Microscope slide was originally called a "slider" first made of ivory or bone, containing specimens held between disks of transparent mica (a rock forming mineral). These were popular in Victorian England until the Royal Microscopical Society introduced the standardized microscope slide in the form of a thin sheet of glass used to hold objects for examination under a microscope. There are a wide variety of microscope slides, but the standard size is a 3" X 1" and about 1.0 mm thick. Different sizes are available for different purposes. The "specimen" that is to be viewed is usually placed on the middle of the slide with another, much thinner square, circle, or rectangular glass piece placed over the specimen. This piece of glass is called a cover slip or cover glass. The cover glass has a dual purpose. It protects the mircrscope's objective lens from contacting the specimen, and it creates an even thickness for your viewing. The thickness of a cover slip is very important for high-resolution microscopy.