CK-12 Foundation
Ck 12: Life Science: Microscopes
[Free Registration/Login may be required to access all resource tools.] A microscope is a tool used to make things that are too small to be seen by the human eye look bigger. Before microscopes were invented in 1595, the smallest things...
University of Arizona
The Biology Project: Studying Cells Tutorial: Size and Biology
Get an overview of light microscopes, scanning electron microscopes and transmission electron microscopes. There is also a brief description of sizes for several microscopic objects.