Although scientists, in principle, have long known that atoms exist, nevertheless a shadow of doubt remained, because no one was able to see the atoms with their eyes.
Now scientists can obtain images of atoms on a computer screen, move atoms on the surface using a special tool - scanning tunneling microscope (STM).
Atoms and Conventional Measuring Instruments
It is impossible to see atoms in a conventional microscope because of the small size of the latter - from four to sixteen billionths of a centimeter in diameter. The hair on the arm is a million times thicker. It is impossible to use ordinary light to illuminate an atom, because the wave of visible light is two to five thousand times the diameter of the atom.
Scanning tunneling microscope
STM is not an optical device with an eyepiece, where you can look into the eye. This is a computerized tool with a special tip, which can be placed very close to the surface under study. When the tip moves, the electrons slip through the gap between the tip and the surface material. As a result, an electric current can be recorded. At the slightest change in the distance between the surface and the tip - electrode, the strength of the electric current changes.
As atoms saw
A surface that seems perfectly smooth to us is very, very lumpy at the atomic level. An electrode registers each elevation, even if it does not exceed the size of an atom.The computer draws a three-dimensional map of the surface, considering each of its atoms. As a result, we can “see” atoms.
Using STM, scientists have learned how to manipulate atoms. At first, the atoms are cooled to minus 270 degrees Celsius, which is very close to the absolute zero temperature, at such a low temperature the atoms become almost motionless.
Using the STM electrode in this case, one can use the magnetic field to move atoms as they see fit and even write words on the surface of the substance. These words are written in the same way as words in books for the blind in Braille. These atomic letters can only be read using STM.
