Final answer:
TEM provides internal views of very thin specimen sections, revealing structures down to individual atoms. SEM, in contrast, offers highly detailed external surface views with a three-dimensional look, making it suitable for observing surface features over a wide range of magnifications.
Step-by-step explanation:
When utilizing a transmission electron microscope (TEM), the intention is typically to observe the internal structures of a specimen, such as organelles and the interiors of membranes. For TEM analysis to be effective, specimens must be prepared in very thin sections. This is accomplished through the use of an ultramicrotome, which slices the specimen finely enough to allow electrons to pass through. The detailed imagery provided by TEM can achieve magnifications up to two million times the size of the original object, enabling the visualization of structures as minute as individual atoms.
In contrast, scanning electron microscopy (SEM) presents an external view by focusing on the surfaces of specimens. SEM slides a beam of electrons across the surface, which interacts with the specimen to produce a highly detailed image that gives a three-dimensional appearance of the surface. SEM is used to view a wide range of object sizes and can magnify surfaces from about 10 to 500,000 times their original size.