Table of Contents
An electron microscope uses a beam of electrons in its microscopic procedure while light microscope uses light.
What is Electron Microscope?
Max Knoll and Ernst Ruska used and invented the electron microscope in 1931. The electron microscope is very complex microscope which requires a high level of technical skills for operation. An electron microscope uses a beam of the electron which is approximately equivalent to 1 nm wavelength. Image formation can be controlled by focusing on electromagnets due to the negative charge on electrons. Specimen preparation is usually involving harsher procedures by using corrosive chemicals, so more skills are required in specimen preparation. There are two most common types of electron microscopes, scanning electron microscope (SEM) and transmission electron microscope (TEM). In transmission electron microscope, an electron beam is passed through an extremely thin section of the specimen and two-dimensional cross section of the specimen has obtained while in the case of scanning electron microscope, the surface structure of the specimen has visualized which provided a 3-D impression. Electron microscope forms greyscale images. However false color electron micrographs are common and beautiful. This microscope cannot view living specimens because electron microscope uses vacuum in a tube so that electrons would not be absorbed by air molecules.
What is Light Microscope?
Dutch spectacle maker, Hans Janson and his son Zacharias invented the first light microscope in late 16th century. The light microscope is also called as an optical microscope. The light microscope uses light which is almost 400 to 700 nm. Simple techniques are used to operate light microscope, and only simple slides of specimens are prepared. Sample preparation generally takes few minutes to few hours for light microscopy, but the surface view of the light microscope is weak. Image formation can be controlled by passing light through glass lenses. This microscope makes image including the range of wavelengths which has provided by the light source and colors are often due to stains rather than the actual colors present in nature. There are two common types of light microscope, compound microscope, and stereo microscope. A stereo microscope is also known as dissecting microscope. A stereo microscope is frequently used to visualize larger, opaque specimens and objects. They usually do not magnify as much as a compound microscope (app 40X-70X) but give a truly stereoscopic image. This is because the image formed to each eye is slightly different. Stereomicroscope does not require elaborate sample preparation. The compound microscope magnifies up to about 1000X. The specimen has to be sufficiently bright and thin for the microscope light to pass through. The specimen is fixed on a slide which is made of glass. The compound microscope cannot produce a 3D view, even if they possess two eye pieces. This is because each one of the eye receives the same image from the objective. The light beam is split into two parts.
Electron microscope vs. Light microscope
- Both electron and light microscopes form larger and more detailed images of small objects that cannot be formed by the human
- Both microscopes are used for research and study purposes in biology, medical sciences, and material
- The electron microscope is very complicated and large.
- The light microscope is very compact and handy.
- Electron microscope can study only fixed specimens
- Light microscope can study both living and fixed specimens.
- Specimens must be hydrates in the electron
- Specimens must not be hydrates in the light
- Object lens of the electron microscope is ultrathin almost 0.1 μm.
- Object lens of the light microscope is thick almost5 μm.
- Vacuum is essential for electron microscope working.
- Vacuum is not essential for light microscope
- Electron microscope employs electromagnets.
- The light microscope uses glass lenses.
- In the electron microscope, the image can be seen only on a fluorescent screen.
- In light microscope, the image can be seen directly.
- Magnification power of electron microscope is almost 300,000.
- Magnification power of a light microscope is almost 4000.
- Resolving power of electron microscope is 0.5-5.0 °A
- Resolving power of a light microscope is 0.25 μm or 250 nm.
- 50,000 or above volt electric current is required for electron microscopy.
- Light microscopy doesn’t need high voltage electricity.