Lab Investigation Lab Investigation 02. The bright-field compound microscope is probably the most important instrument you will use in any biology course. Objects such as bacteria, mold spores, plant cells, or animal tissues, too small to be seen with the unaided eye will become highly magnified, thus revealing minute details. Logic would indicate that the more we magnify the image of a cell, the more detail we can see. Unfortunately, this is not true.
Light rays passing through curved surfaces are bent.
This bending of light produces an enlarged image. But the best research microscopes can currently magnify only 1500 to 2500 diameters. The limiting factor is the nature of light. Resolving power or resolution is the ability to distinguish separate images of objects that fall very close together on the retina of the eye. Since the human eye cannot ordinarily resolve objects separated by less than 0.1 mm, a microscope can extend the resolving power of the eye about 400 times.