What are the two most common types of microscopes?

The two most common types of microscopes are light and electron microscopes. 

1. Light Microscope: A light microscope uses visible light to illuminate specimens. The device uses a series of glass lenses that magnify the image of the specimen, allowing for the visualization of small details. The first lens focuses a beam of light onto or through the specimen, and the convex objective lenses in the microscope magnify the image formed. Light microscopes are versatile, easy to use, and do not require extensive sample preparation. They can be used for observing live specimens, allowing researchers to study cellular processes in real time. Light microscopes are commonly used in cell biology to observe living or fixed cells and tissues and in medical laboratories for routine examination of biological samples, such as blood smears and tissue sections.
2. Electron Microscope: An electron microscope uses a beam of electrons instead of visible light to create magnified images of very small objects. There are two main types of electron microscopes – transmission and scanning electron microscopes. In a transmission electron microscope (TEM), electrons pass through thin sections of the specimen, creating a highly detailed internal image. In a scanning electron microscope, electrons are scattered off the surface of the specimen, providing a 3D surface view. Electron microscopes can achieve much higher magnifications and higher resolutions, providing detailed images of small structures. Electron microscopes are used to study the ultrastructure of cells, including organelles and other subcellular components. Researchers use these devices for visualizing and analyzing the morphology of viruses and to examine the structure of materials at the nanoscale.