Seeing Atoms

In the traditional sense of the word, we can never really ‘see’ atoms. However, scientists have devised ways to recreate their images with great accuracy and spectacular details.

Optical Microscopes

Optical or light microscopes allow us to magnify an object almost 2,000 times which is enough to spot plant and animal cells but not enough to get a detailed view. The reason that light microscopes have such limitations is the wavelength of light. Certain nano-particles are smaller than that wavelength and hence light cannot hit them and form images. They are missed by light.

Electron Microscopes

Then came the electron microscopes which fired beams of electrons on a surface and recreated an image based on the pattern of their scattering. It was a drastic step forward as it allowed to ‘see’ things 500,000 times their size. With the help of an electron microscopes, one can take images of the insides of cells in some detail. There is a more powerful type of electron microscope, called the Transmission electron microscope, which produces a magnification range of about  10,000,000x. It can produce great detailed pictures of cells and even atoms.Electron MicroscopesScanning Probe Microscopes

The latest type of microscope is the Scanning Probe microscope. These microscopes did not use light or electrons which had limitations on their outreach. There are various types of SPC.

The most widely used is the Atomic probe microscope which uses a nano-scale ‘finger’ or a tip which is almost the size of an atom. This atomically thin needle like structure is run on sample surfaces and an image is recreated based on its interaction with the surface.

Another type is the Magnetic Force microscope which forms images based on the change in the magnetic field on an atomic level.

The Scanning Tunneling Microscope which recreates images based on the change in electrical energy between the needle and the atomic surface.

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