A microfiche is a single sheet of plastic that contains several images of pages of text, whereas microfilm is a long spool of plastic film that winds and rewinds to view images of text. In both instances, these microforms require a projection system whereby images of microfiche and microfilm appear on a backlit screen to be viewed.Know More
Microfiche is usually 6 inches by 4 inches per sheet. Users place microfiche under a plate of glass. Once under the glass, light shines behind or beneath the plastic microfiche while a lens increases the image size. The image from the lens is then projected onto a small screen so individuals can read the text.
Microfilm is viewed in much the same way, only spools move microfilm back and forth under the plate of glass similar to a spool of movie celluloid. Microfilm holds many more document images than a single sheet of microfiche. Technology has improved to allow microfilm and microfiche images to be viewed on digital computer screens using special programs.
One of the largest microform collections in the world is housed at the Library of Congress. More than 7 million pieces can be viewed by researchers in the Microform Reading Room. The collection includes ancient manuscripts, posters, photographs, archives, rare publications and artifacts.Learn more about Public Records
The University of Arizona maintains copies of the Arizona Republic newspaper on microfilm. Its collection includes all issues of the Arizona Republic published between 1930 and 2010. Issues published after 2010 are available in other formats, such as digital microfilm, print and online databases.Full Answer >
Computer output microfilm is the product of copying information from electronic media onto microfilm. COM technology, with a history that dates back to the first patent for microphotography in 1839, has been used for document and newspaper archival since the 1920s. And, with the advent of the personal computer, computer-produced microforms are becoming more popular for non-library use, such as storing catalogs and patient records.Full Answer >
Local winds are one of the main types of winds caused by differences in air temperature. The temperature differences often develop through the day as the sun heats the air and land, but they can also be formed when surfaces do not heat or cool evenly.Full Answer >
Global winds are a system of wind patterns distributing warm air unevenly across Earth. If Earth did not rotate, winds would move from the equator to their respective poles. Because Earth rotates, winds appear to be moving east in the Coriolis effect.Full Answer >