Why are microorganisms hard to see in wet preparation

If you are using a microscope the light is below the slide and shining through the specimen. Microorganisms with no real solid structures internally, it is almost transparent with the light source underneath. Plus the size of a microbe is about 2 micrometers (very small). A red blood cell is about 6 to 8 micrometers and a strand of hair is about 50 micrometers in diameter to give you some idea of the size. They do make stains that will help visualize microganixms with a microscope. The scope should have a 100x oil objective and a 10x eyepiece. The gold standard of stains for this is call the "Gram Stain". It is made up of a series of stain solutions, crystal violet, safarin, iodine, and alcohol. You can probably find the recipe in a Microbiolgoy textbook at the library. Hope this helps.