Scientists use an instrument called a microscope to view objects and structures that are very small. There are several different types of microscopes that they can use. The most common type is the light microscope. Another type often used is the scanning electron microscope, or SEM.

Light microscopes, like the one shown here, are relatively inexpensive and easy to use, but they do not provide really high magnification. A SEM provides much higher magnification but is much more expensive and complex.