1. Lighting sources: one uses electricity and the other uses light.
The electron microscope is illuminated by an electron gun, which emits an electron flow as soon as it is turned on. The wave length of this thing is outrageous! For example, it's like putting a "high-definition probe" on a microscope, and even things as small as atoms can be photographed clearly. The optical microscope is much more grounded, and directly uses the desk lamp at home and the sunlight outside the window as lighting, but the wavelength of light wave is much longer than that of electron flow, so the fineness of seeing things is naturally poor. Simply put, the electron microscope is a "top photographer" and the optical microscope is a "family recorder".
2. the lens: electromagnetic coil VS glass, the principle is very different.
The lens in the electron microscope is an electromagnetic coil. When it is electrified, it can generate a magnetic field, which "gathers" the electron flow together to enlarge the image like a magnet attracts a small nail. The lens of an optical microscope is made of glass, and the light will refract when it shines, just like looking at ants through a magnifying glass and "snapping" things up. Although they are all magnified, one depends on the magnetic field to "hold" electrons and the other depends on the light to "turn", which are completely different.
3. the imaging principle: electronic shade VS light shade
The imaging process of electron microscope is super cool: after the electron beam is amplified by the electromagnetic lens, it can be imaged on the screen. Why are the images deep and shallow? Because the electron beam will "bump around" when it hits the atoms in the sample, the more it hits, the rarer the electrons will be and the lighter the image color will be. Optical microscope imaging is easy to understand, different parts of the sample absorb different light, where it absorbs more light is dark, and where it absorbs less light is bright, just like shining a flashlight on different colors of glass, and the amount of light transmission determines the brightness.
4. specimen preparation: "devil process" VS "home operation"
If you want to see the sample under an electron microscope, the process is as complicated as "devil training"! From taking materials and fixing shapes to dehydration and embedding, special reagents are used in each step, and the operation method is also accurate to the "hair level". Finally, it is necessary to use a slicer to cut into thin slices thousands of times thinner than hair. On the other hand, optical microscope, preparing a specimen is like cooking a home-cooked dish. Just put the sample on the glass slide, whether it's a tissue section or a cell smear, and you can look at it just by fiddling with it a few times.
After all, these two microscopes have their own "killer". Electron microscope specializes in treating "intractable diseases" in scientific research, which can reveal the secrets of atomic structure; Optical microscope is more suitable for daily observation, and it is good at looking at cells in biology class and crops in agricultural research. Next time you see the beautiful picture of the micro-world, guess which "master" is the masterpiece! Have you ever used a microscope in your life? Welcome to share your "micro adventure" in the comment area!
