A major disadvantage of the electron microscope is its inability to analyze live specimens.
Why Electron Microscopes Can't View Live Samples
Electron microscopes use a beam of electrons to create images of very small objects. However, for this to work effectively, several specific conditions must be met, as discussed below:
- Vacuum Requirement: Electrons are highly susceptible to scattering when they collide with air molecules. Therefore, to avoid image distortion, the sample and the electron beam must be placed inside a vacuum chamber. This prevents the electrons from interacting with air molecules, allowing them to reach the specimen and produce a clear image. The reference clearly states that "samples must be analyzed in a vacuum," confirming this essential requirement.
- Consequence: Because the sample must be placed inside a vacuum, live specimens cannot be studied. The vacuum environment would quickly destroy the living tissue, meaning that electron microscopy is not compatible with real-time observation of living processes. As highlighted by the reference, "This means that live specimens cannot be studied by this technique."
Additional Considerations:
| Feature | Electron Microscope | Optical Microscope |
|---|---|---|
| Specimen Preparation | Complex, includes vacuum | Simple, little preparation needed |
| Live Samples? | No | Yes |
| Resolution | Very High | Moderate |
| Magnification | Very High | Moderate |
Example:
Imagine trying to observe the behavior of a live cell under an electron microscope. Unfortunately, the process of placing that cell inside a vacuum would kill it, rendering any observed images of the cell not representative of a living cell's behavior.
Summary
In conclusion, the primary drawback of using an electron microscope is that the sample must be placed in a vacuum for proper imaging, thereby eliminating the possibility of observing live specimens. This limits the technique to prepared, non-living samples.
