There are two different types of microscope slides in general use. The common flat glass slide, and the depression or well slide. Both are rectangular and measure approximately 1 x 3 inches (25 x 75 mm). Depression slides have an indentation in the center to hold a drop of liquid, cost considerably more than the flat variety, and are usually used without a cover slip.
Standard slides are made of glass or plastic. For most purposes, glass slides of 1 to 1.2 mm thick are used. When working with high power objectives and condensers, the slide thickness should be reduced to 0.8 to 1 mm.
You can have some glass piece of that thickness.Glass cover slips should be handled carefully as they are very fragile and break easily. Cover slips measure 18 or 20 mm square and the glass variety is available in two thicknesses, Number 1 and Number 2. Number 1 cover glasses are 0.13 - 0.17 mm thick and are recommended for oil immersion or high resolution work. Number 2 slips are 0.17 - 0.25 thick and are used for general applications. Point is how will you manage coverslip?
You can have drop of water from some pond and see under microscope...few protists Good luck