I know the machine fires electrons at a sample and the electrons are reflected back. How does that translate into a super detailed image? Why is it higher resolution than a light microscope? Why can it only use dead samples?
Edit: Also, why is it in black and white?
In: Technology
Electron microscopes operate under high vacuum. Electrons dont travel very far in air and even if they did, detail would be blurred because of the collisions with air molecules. Living things don’t survive very long in a vacuum.
There are two types, transmission (TEM) and scanning (SEM).
A TEM is rather similar to an optical microscope. A beam of electrons passes through a thin sample and is focussed by electrical coils, instead of glass lenses, to make the image.
An SEM scans a fine beam of electrons across the sample and records the amount reflected from each point to build up the image. It’s a bit like you sitting in a dark room with a laser pointer. You wave the dot across the far wall and the changes in brightness tell you about the objects there. Although SEMs generally have less magnification than TEMs, they can deal with 3D samples that need much less preparation.
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