Both light microscopes and electron microscopes use radiation (light or electron beams) to form larger and more detailed images of objects which cannot be seen clearly through an unaided eye.
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Light Microscope vs Electron Microscope (Table Form)
However, each of these microscopes has distinct features and is suitable for different purposes.
S.N. | Character | Light Microscope | Electron Microscope |
1. | Alternatively known as | Optical microscope | Beam microscope |
2. | Invented by | It is believed that Dutch spectacles makers Zacharius Jansen and his father Hans were the first to invent the compound microscope in the 16th century. | In 1931 physicist Ernst Ruska and German engineer Max Knoll. |
3. | Illuminating source | Uses light (approx wavelength 400-700 nm) to illuminate the objects under view. | Uses a beam of electrons (approx equivalent wavelength 1 nm) to make objects larger for a detailed view. |
4. | Principle | The image is formed by the absorption of light waves. | The image is formed by scattering or transmission of electrons. |
5. | Structure | Light microscopes are smaller and lighter. | Heavier and larger in size. |
6. | Lenses used | Lenses are made of glass. | Lenses are made of electromagnets. |
7. | Vacuum | Not used under a vacuum | Operates under a high vacuum |
8. | Specimen type | Fixed or unfixed, stained or unstained, living or non-living. | Fixed, stained, and non-living. |
9. | Specimen observed | Both live and dead specimens can be observed. | Only dead specimens are possible to be observed. |
10. | Specimen preparation | Less tedious and simple. | It generally involves harsher processes, e.g. using corrosive chemicals. More skill required – both to prepare specimens and to interpret EM images (due to artifacts). |
11. | Preparation time | Specimen preparation takes usually a few minutes to hours. | Specimen preparation takes usually takes a few days. |
12. | Thickness of specimen | 5 micrometer or thicker | Ultra-thin, 0.1 micrometers or below |
13. | Dehydration of Specimen | Specimens need not be dehydrated before viewing. | Only dehydrated specimens are used. |
14. | Coating of specimen | Stained by colored dyes for proper visualization. | Coated with heavy metals to reflect electrons. |
15. | Mounting of specimen | Mounted on the glass slide. | Mounted on the metallic grid (mostly copper). |
16. | Focusing | Done by adjusting the lens position mechanically. | Done by adjusting the power of the electric current to the electromagnetic lenses. |
17. | Magnification power | Low magnification of up to 1,500x. | High magnification of up to 1,000,000x. |
18. | Resolving power | Low resolving power, usually below 0.30µm. | The high resolving power of up to 0.001µm, about 250 times higher than the light microscope. |
19. | Viewing of the image formed | Light microscope images can be viewed directly. Images are viewed by the eyes through the eyepiece. | Images are viewed on a photographic plate or zinc sulfate fluorescent screen. |
20. | Nature of Image formed | Poor surface view | Good surface view and internal details |
21. | Image Color | Colored images. | Electron microscopes produce grayscale (sometimes called “black and white”) images (except “false-color” electron micrographs). |
22. | Image dimension | Image plane “flat” (2D). | 2D only in a Transmission electron microscope (TEM); Scanning electron microscope (SEM) images give depth information that seems like 3D. |
23. | Living processes | Visualization of living processes such as microscopic pond life in action and even cell division is possible. | Living processes cannot be viewed. |
24. | Room settings | No special settings are required. | It must be used in a room where humidity, pressure, and temperature are controlled. |
25. | Simplicity in use | Simple to use | Users require technical skills |
26. | Electric Current | No need for high voltage electricity. | A high voltage electric current is required (50,000 V or above). |
27. | Filaments | No filaments are used. | Tungsten filaments are used to generate electrons. |
28. | Cooling System | Absent | Cooling system present to pacify the heat generated due to high voltage electric current. |
29. | Radiation leakage | No radiation risk. | Risk of radiation leakage. |
30. | Complexity | Less complex | Complex |
31. | Expense | Cheap to buy and has low maintenance costs. | Very expensive to buy as well as to maintain. |
32. | Suitability / Practicality | Suitable for most basic functions, and is very common in schools and other learning institutions. | Limited to specialized use such as research. |
33. | Advantages | Easy to use Cheap True color but sometimes require staining Live specimens | High resolution Provide detailed images of surface structures and interior structures High magnification 3D images |
34. | Disadvantages | Low resolution due to shorter wavelength of light (0.2nm) Low magnification The specimen used is thin. | Expensive Requires extensive training Sample must be dead Black and white/false-color image |
35. | Types/ Variants | Dark-field microscope Phase-contrast microscope Fluorescent microscope Confocal microscope Polarized microscope Differential interference contrast microscope | Transmission electron microscope (TEM) Scanning electron microscope (SEM) |
36. | Application | It is used for the study of detailed gross internal structure. | It is used in the study of the external surface, the ultrastructure of cells, and very small organisms. |
References
- Manandhar S. (2013). A practical approach to microbiology. Revised 2nd Edition. National Book Centre: Kathmandu.
- https://theydiffer.com/difference-between-a-light-microscope-and-an-electron-microscope/
- https://www.majordifferences.com/2013/10/difference-between-electron-microscope.html
- http://www.ivyroses.com/Biology/Techniques/light-microscope-vs-electron-microscope.php
- https://biodifferences.com/difference-between-light-microscope-and-electron-microscope.html
- https://www.easybiologyclass.com/light-microscope-vs-electron-microscope-similarities-differences-comparison-table/
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