# 9.1: Using Microscopes

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## The Microscope

### Dissecting Microscope

A dissecting microscope generally has lower magnification and uses incident light, meaning the light shines onto (not through) the specimen to view it.

### Compound Microscope

A compound microscope is used for viewing small samples or pieces of a larger specimen at higher magnification. This type of microscope uses transmitted light, where the light must pass through the specimen to view it.

## Making and Staining Slides

There are many ways to make a slide. Preparation method and technique will vary, depending on your specimen and what you need to see. Below are some basic guidelines, but you should experiment with what works best for you and your specimen.

With compound microscopes, the light must pass through the specimen. For this to work, your prepared sample must be quite thin. Many prepared slides are made using a machine called a microtome to achieve the extremely thin, even sections needed to see many anatomical features. As a human trying to perform this process, you'll need as much practice as possible to get a good thin section.

Video $$\PageIndex{1}$$: This video provides a demonstration of making thin cross-sections by hand for plant material such as stems and roots; includes a demonstration of staining the material using TBO (toluidine blue O), a metachromatic stain useful for many plant materials. [See Episode 6 for how to prepare TBO.] Sourced from YouTube.

## Focusing with a Compound Microscope

Video $$\PageIndex{2}$$: Dr. Patrick demonstrates the steps in focusing a compound light microscope from 10X to 100X. She shows you how the field of view changes with each lens. The use of immersion oil for the 100X lens is specifically shown. Sourced from YouTube.