Introduction:
Microorganisms are much too small to be seen with the unaided eye; they must be
observed with a microscope, The word microscope is derived from the Latin word
micro (small) and the Greek word skopos (to look at).
Some microbes are more readily visible than others because of their larger
size or more easily observable features. Many microbes, however, must undergo
several staining procedures to be seen clearly.
Units of Measurement:
When measuring microorganisms, we use the metric system. A major advantage of
the metric system is that units relate to each other by factors of 10. Thus, 1 meter (m)
equals 10 decimeters (dm) or 100 centimeters (cm) or 1000 millimeters (mm).
Microorganisms are measured in even smaller units, such as micrometers and
nanometers. A micrometer (μm) equals 0.000001 m (10 ̵⁶). The prefix micro indicates
the unit following it should be divided by 1 million, or 10⁶. A nanometer (nm) equals
0.000000001 m (10 ̵⁹m)