Microscopy and Measurement

Among the most widely used tools in biology are microscopes. A microscope is an instrument that produces an enlarged image of an object. Biologists use microscopes to study organisms, cells, and cell parts that are too small to otherwise be seen. Microscopes both enlarge the image made by an object and show it's details. The increase of an objects apparent size is magnification. The power to show details clearly refers to resolution. Microscopes vary in powers of magnification and resolution. To see small organisms and cells, biologists typically use a compound light microscope (LM). To be viewed with a compound microscope, a specimen is mounted on a glass slide. The specimen must be sliced thin enough to be transparent, or it must be very small. The slide holding the specimen is placed over the opening in the stage of the microscope. A light source, a light bulb or mirror in the base, directs light upward. Light passes through the specimen and through the objective lens, which is positioned directly above the specimen. The objective lens enlarges the image of the specimen. This magnified image tube to the