Projection
microscopes are best and ideal to use especially for classroom applications. The
projecting microscope forms a highly enlarged real image of some small object
on a distant screen. It differs from the viewing microscope with which the
viewer sees a virtual image, located in the same plane as the object at a
distance of 25 cm from the eye - the closest distance of distinct vision.
originally found here;- http://www.lab360.co.in/microscopes-telescopes.htm