Microfilm - a 35mm strip of transparent film that is wrapped around a small reel (just like old movies!)
Microfiche - a transparent card that is usually 4x6 inches.
Microcard - a non-transparent card that is approximately 3x5 inches. Microprint - a larger non-transparent card, normally 5x7 inches.
Ask a Librarian if you think you need to use microform material. In addition to helping you find the individual items, they may be able to help you find the document in a more readily accessible format.
Microform material saves physical space and helps preserve information from physical decay. Use a microform reader to read through these materials - we have one on the 2nd floor of Hale Library near Library Help, and more on the 3rd floor.