Microscopy

Microscopy

Light microscopes were invented first, with a maximum resolution of 200nm.
- The eyepiece lens often has x10 magnification, then the 3 objective lenses will have different magnifications (x5, x10, and x25).
- The stage holds the specimen which is on a microscope slide under a cover slip.
- Course focus moves the stage closer and further from the chosen objective lens to roughly focus the sample, and fine focus moves the stage slowly to adjust.

Electron microscopes were invented later and have a max. resolution of 0.1 nm, allowing for a better understanding of sub-cellular structures.
- Transmission electron microscope (TEM) fires a beam of electrons through a thin slice of the specimen. Electrons that pass through the specimen are detected and used to make the image.
- Scanning electron microscope (SEM) fires a beam of electrons across the surface of the specimen. Electrons scatter from the surface and are detected to make the image.

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